Braiding Operations for a Topological Josephson Junction Array using SFQ Current PulsesTakuro Funazawa; Masato Naruse; Hiroaki Myoren
Journal of Physics: Conference Series,
巻：2323,
号：1,
開始ページ：012035,
終了ページ：012035, 2022年08月
Abstract
Majorana bound states (MBSs) can occur in topological Josephson junction (JJ) arrays with the presence of a fractional vortex with 2π-phase winding. It has been theoretically shown that the braiding operation can be achieved by using current pulses, compatible with single flux quantum (SFQ) technology. Therefore, we designed an SFQ logic circuit for the braiding operations of the topological JJ array using single flux quanta in a conventional JJ array. Braiding operations could be realized by an SFQ logic circuit with double flux quantum driver. To obtain positive and negative current pulses using the SFQ logic circuit, we used SFQ logic circuits with ac biasing for simulation. Finally, we confirmed the CNOT operation using an array-type SFQ circuit by means of simulation and estimated the CNOT operation speed.
IOP Publishing, 研究論文（学術雑誌）
DOI：https://doi.org/10.1088/1742-6596/2323/1/012035DOI ID：10.1088/1742-6596/2323/1/012035,
ISSN：1742-6588,
eISSN：1742-6596 Development of embedded STJ for large format array X-ray detector Y. Ito; M. Aoyagi; C. Otani; M. Naruse; H. Myoren; T. Taino
Journal of Physics: Conference Series,
巻：1590,
号：1, 2020年07月
We have been developing an embedded superconducting tunnel junction (e-STJ) for a large-format array X-ray detector. Compared with the conventional STJ array, the e-STJ array is suitable for enlarging the detection area effectively because the e-STJ detector utilizes a three-dimensional packaging technology. To investigate the relationship between the fabrication method and the electric characteristics of the e-STJ, we designed and fabricated three types of simplified e-STJ and measured their subgap leakage current in the temperature range from 4.2 K to 0.3 K. We found that the roughness of the embedding hole on the Si substrate and the contact part between the embedded STJ and the side of the embedding hole affected the subgap leakage current.
Institute of Physics Publishing, 英語, 研究論文（国際会議プロシーディングス）
DOI：https://doi.org/10.1088/1742-6596/1590/1/012035DOI ID：10.1088/1742-6596/1590/1/012035,
ISSN：1742-6596,
SCOPUS ID：85090054199 Niobium-Based Kinetic Inductance Detectors for High-Energy Applications Masato Naruse; Masahiro Kuwata; Tomohiko Ando; Yuki Waga; Tohru Taino; Hiroaki Myoren
IEICE TRANSACTIONS ON ELECTRONICS,
巻：E103C,
号：5,
開始ページ：204,
終了ページ：211, 2020年05月
A lumped element kinetic inductance detector (LeKID) relying on a superconducting resonator is a promising candidate for sensing high energy particles such as neutrinos, X-rays, gamma-rays, alpha particles, and the particles found in the dark matter owing to its large-format capability and high sensitivity. To develop a high energy camera, we formulated design rules based on the experimental results from niobium (Nb)-based LeKIDs at 1 K irradiated with alpha-particles of 5.49 MeV. We defined the design rules using the electromagnetic simulations for minimizing the crosstalk. The neighboring pixels were fixed at 150 mu m with a frequency separation of 250 MHz from each other to reduce the crosstalk signal as low as the amplifier-limited noise level. We examined the characteristics of the Nb-based resonators, where the signal decay time was controlled in the range of 0.5-50 mu s by changing the designed quality factor of the detectors. The amplifier noise was observed to restrict the performance of our device, as expected. We improved the energy resolution by reducing the filling factor of inductor lines. The best energy resolution of 26 for the alpha particle of 5.49 MeV was observed in our device.
IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1587/transele.2019SEI0001DOI ID：10.1587/transele.2019SEI0001,
ISSN：1745-1353,
Web of Science ID：WOS:000530666500003 High-Resolution Digital SQUID Magnetometer using Sub-Flux Quantum Feedback Hiroaki Myoren; Kosuke Okabe; Ryo Matsunawa; Kohki Itagaki; Masato Naruse; Tohru Taino
14TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS2019),
巻：1559, 2020年
Digital SQUIDs with the single flux quantum (SFQ) feedback have attracted much attention because of the feasibility of realizing a wide dynamic range and high slew rate for digital magnetometers. In order to realize higher resolution, we have studied a digital SQUID with sub-flux quantum feedback. Combining the sub-flux quantum feedback to a feedback loop and the direct SFQ feedback to a main loop triggered by carry SFQ pulses from an up/down counter. In this study, we discuss the method of multi-flux quantum generation and compact design of the SFQ up/down counter for high-speed operation of the digital SQUID magnetometer.
IOP PUBLISHING LTD, 英語, 研究論文（国際会議プロシーディングス）
DOI：https://doi.org/10.1088/1742-6596/1559/1/012013DOI ID：10.1088/1742-6596/1559/1/012013,
ISSN：1742-6588,
eISSN：1742-6596,
Web of Science ID：WOS:000558737600013 Design of Digital Filter for Digital SQUID With Sub-Flux Quantum Feedback Resolution Hiroaki Myoren; Kousuke Okabe; Ryo Matsunawa; Masato Naruse; Tohru Taino
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：29,
号：5, 2019年08月
Digital SQUIDs with the single flux quantum (SFQ) feedback have attracted much attention because of the feasibility of realizing a wide dynamic range and high slew rate. In order to realize higher resolution, we have studied the performance of an advanced, digital SQUID configuration offering sub-flux quantum feedback. Combining the sub-flux quantum feedback to a feedback loop and the direct SFQ feedback to a main loop triggered by carry SFQ pulses from an up/down counter. After optimization of the circuit, we confirmed the maximum magnetic field amplitude exceed 1 mu T, the magnetic field noise is lower than 100 pT/root Hz with a signal band frequency of 1.22 MHz. Using a first-order sinc filter, we could implement the digital SQUID magnetometer at low-temperature with reasonable noise reduction performance and the binary data rate reduction in order to transfer the data from low temperature circuit to the room temperature electronics.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2019.2908625DOI ID：10.1109/TASC.2019.2908625,
ISSN：1051-8223,
eISSN：1558-2515,
Web of Science ID：WOS:000467071300001 Readout Circuit Based on Single-Flux-Quantum Logic Circuit for Photon-Number-Resolving SNSPD Array Hiroaki Myoren; Satoshi Denda; Kazuki Ota; Masato Naruse; Tohru Taino; Lin Kang; Jian Chen; Peiheng Wu
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：28,
号：4, 2018年06月
A read-out circuit for photon-number-resolving superconducting nanowire single-photon detector (SNSPD) based on the single-flux-quantum (SFQ) circuit was designed and the basic performance of the fabricated circuit was confirmed. The current pulse output from an SNSPD array was converted to a SFQ pulse. The SFQ pulse triggered two stacks of double-flux-quantum (DFQ) amplifiers. A single block of a 40-series DFQ amplifier (DFQA) generated 2.3-mV voltage with a rising time of 400 ps for an operation frequency of 1.25 GHz, and the two stacks of DFQA generated 4.6-mV voltage when the SFQ pulse trains supplied both the DFQAs. The total voltage generated by twelve-series of 40-series DFQAs was expected to be 27.6 mV, with the same rising time of 400 ps. Using the fabricated circuit, the 40-series DFQA and the two stacks of the 40-series DFQA generated 2.3- and 4.6-mV voltage, respectively. The output voltage of the SFQ readout circuit was compatible to a room-temperature photon counter with a wide-band low-noise amplifier operating at low temperature.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2018.2809483DOI ID：10.1109/TASC.2018.2809483,
ISSN：1051-8223,
eISSN：1558-2515,
Web of Science ID：WOS:000431524600001 Absorber-coupled lumped element kinetic inductance detectors for gamma-rays Masato Naruse; Noriaki Miyamoto; Tohru Taino; Hiroaki Myoren
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS,
巻：541,
開始ページ：36,
終了ページ：39, 2017年10月
We propose gamma-ray detectors based on superconducting resonators that can be largely multiplexed and show potential for quick response time, high spatial resolution, and high energy resolution. The resonators were fabricated with a niobium film on a silicon wafer. Eight out of ten detectors could be operated at 0.3 K. The detectors were coupled to a 2-mm-thick lead absorber and examined with a cesium 137 source. The pulse decay time was 3.6 mu s and energy resolution was 3.8 keV at 662 keV. We also describe the resonant properties of each detector. The proposed detectors are suitable for use as food-screening systems. (C) 2017 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.physc.2017.08.001DOI ID：10.1016/j.physc.2017.08.001,
ISSN：0921-4534,
eISSN：1873-2143,
Web of Science ID：WOS:000410647600006 Improving the spatial resolution of superconducting tunnel junction THz wave detectors using a modified LiNbO3 absorber M. Sone; N. Igarashi; M. Naruse; H. Myoren; Y. Sasaki; C. Otani; T. Taino
Journal of Physics: Conference Series,
巻：871,
号：1, 2017年07月,
［査読有り］We proposed a superconducting tunnel junction (STJ) detector for terahertz (THz) waves with a modified substrate absorber. The absorber of each STJ was isolated by trenches in order to restrict the diffusion of phonons generated by THz waves, which are made with a dicing process. We evaluated the diffusion characteristics of phonons in the LiNbO3 substrate by detecting THz photons. We found that the phonon diffusion length in a 500-μm-thick LiNbO3 substrate was over 1 mm. No degradation of the current - voltage (I-V) characteristics of the STJ after performing the dicing process.
Institute of Physics Publishing, 英語, 研究論文（国際会議プロシーディングス）
DOI：https://doi.org/10.1088/1742-6596/871/1/012069DOI ID：10.1088/1742-6596/871/1/012069,
ISSN：1742-6596,
SCOPUS ID：85028005068 Development of STJ for neutron detector on Si-LBO hybrid substrate by surface-activated room-temperature bondingS. Endo; G. Fujii; M. Ukibe; H. Takagi; M. Ohkubo; M. Naruse; H. Myoren; C. Otani; T. Taino
Journal of Physics: Conference Series,
巻：871,
号：1, 2017年07月,
［査読有り］We have been developing superconducting tunnel junctions (STJs) for neutron detector on a Si-Li2B4O7 (LBO) hybrid substrate. An active area of each STJ was limited by dicing in order to obtain high spatial resolution. The Si-LBO hybrid substrate was bonded by a surface-activated room-temperature bonding. In this bonding method, the Si and LBO surfaces were sputter-etched by high energy Ar ion beam and bonded in a vacuum. We fabricated STJs on the Si-LBO hybrid substrate and measured their current-voltage characteristic. Their leakage currents (Ileak) were <
10 nA, and so we succeeded in fabricating STJs on the Si-LBO hybrid substrate, which can be expected to operate as neutron detectors with high performance.
Institute of Physics Publishing, 英語, 研究論文（国際会議プロシーディングス）
DOI：https://doi.org/10.1088/1742-6596/871/1/012070DOI ID：10.1088/1742-6596/871/1/012070,
ISSN：1742-6596,
ORCID：44982367,
SCOPUS ID：85027976830 Noise Properties of Digital SQUID Using Double Relaxation Oscillation SQUID Comparator With Relaxation Oscillation Resonant Circuit Hiroaki Myoren; Ryota Kobayashi; Kenji Kumagai; Masato Naruse; Tohru Taino
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：27,
号：4, 2017年06月,
［査読有り］We designed a digital superconducting quantum interference device (SQUID) system that contains a double relaxation oscillation SQUID (DROS) as a magnetic flux comparator that is connected to an additional relaxation oscillation (RO) circuit with mutually coupled inductances. In the designed digital SQUID, the RO circuit works as a resonator and increases the relaxation oscillation frequency without decreasing the input current of dc/SFQ converters. Numerical simulation shows that the digital SQUID system can operate up to 7 GHz. A fabricated digital SQUID using a DROS comparator with an RO circuit provides correct digital SQUID operation. For a magnetometer using the digital SQUID system, we can realize a magnetic field noise less than 1 pT/root Hz with a small signal bandwidth of more than 10 MHz.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2017.2677422DOI ID：10.1109/TASC.2017.2677422,
ISSN：1051-8223,
eISSN：1558-2515,
Web of Science ID：WOS:000399937400001 Fabrication of superconducting tunnel junctions with embedded coil for applying magnetic field Kenji Yamaguchi; Hiroshi Nakagawa; Masahiro Aoyagi; Masato Naruse; Hiroaki Myoren; Tohru Taino
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS,
巻：530,
開始ページ：90,
終了ページ：92, 2016年11月,
［査読有り］We have proposed and demonstrated a superconducting tunnel junction (STJ) with an embedded coil for applying a magnetic field. The STJ was fabricated on the coil, which was embedded in a Si substrate. The coil in the Si substrate consists of superconducting microstrip lines and applies a magnetic field to the STJ to suppress the dc Josephson current. The embedded coil was designed with a line and space of 3 mu m and a thickness of 120 nm. To planarize the coil, we employed chemical mechanical polishing (CMP) in our fabrication process. In this STJ, the maximum current of the embedded coil was 28 mA, which corresponded to the maximum magnetic field of 11.76 mT. (C) 2016 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.physc.2016.03.010DOI ID：10.1016/j.physc.2016.03.010,
ISSN：0921-4534,
eISSN：1873-2143,
Web of Science ID：WOS:000389518400027 Fabrication of TiN/AlN/TiN tunnel junctions Takeru Nakayama; Masato Naruse; Hiroaki Myoren; Tohru Taino
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS,
巻：530,
開始ページ：87,
終了ページ：89, 2016年11月,
［査読有り］We have fabricated TiN/AlN/TiN tunnel junctions with an epitaxial layer. The critical temperature of TiN can be changed in the range from 0.5 to 5.0 K. Therefore, it is easy to set 5.0 K as the target critical temperature. When a Superconducting Tunnel Junction (STJ) is operated as a photon detector, it is necessary to cool it to within 0.1 K of the critical temperature in consideration of the noise of the thermally stimulated currents. Because 0.3 K was desirable, as for the manufacture of general purpose photon detectors, the critical temperature 5.0 K. TiN and AlN films were deposited by dc and rf magnetron sputtering in a load-lock sputtering system at ambient substrate temperatures. The junctions have a gap voltage of V-g = 1.1 mV, and critical current density of J(c) = 0.24 A/cm(2), and R-sg/R-n of 7.2, and low subgap leakage current (I-sub@ 500 mu V = 180 nA). We report our experiment system, the manufacture method and the junction properties in this paper. (C) 2016 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.physc.2016.04.005DOI ID：10.1016/j.physc.2016.04.005,
ISSN：0921-4534,
eISSN：1873-2143,
Web of Science ID：WOS:000389518400026 Design and Magnetic Field Noise of Magnetometer Using Digital SQUID With Subflux Quantum Feedback Hiroaki Myoren; Kouhei Takatoku; Masato Naruse; Tohru Taino
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：26,
号：5, 2016年08月,
［査読有り］Digital superconducting quantum interference devices (SQUIDs) based on single-flux quantum (SFQ) logic have attractive characteristics such as wide dynamic ranges and high slew rates. However, the resolution of a typical digital SQUID is limited by SFQ feedback. To realize lower magnetic field noise by magnetometers using digital SQUIDs, we have adopted two feedback combinations: one, utilizing the SFQ input/output for a main loop and the other, using a mutually coupled loop. The main loop receives direct Phi(0) feedback and subflux quantum feedback Phi(0)/n, where n is an integer from the mutually coupled loop. The flux resolution for the digital SQUID shows improvement with increasing n and reaches below 40 m Phi(0) at n = 2(10); however, the slew rate decreases with increasing n and reaches 1.22 x 10(6)Phi(0)/s at f(c) = 1.25 GHz and n = 2(10). For amagnetometer using a digital SQUID with a pickup loop, we confirmed a magnetic field noise of less than 100 fT/root Hz with a signal bandwidth of 1 MHz for operation frequency f(c) of 20 GHz.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2016.2569500DOI ID：10.1109/TASC.2016.2569500,
ISSN：1051-8223,
eISSN：1558-2515,
Web of Science ID：WOS:000380321300001 Gate-Tunable Transport Properties of In Situ Capped Bi2Te3 Topological Insulator Thin Films Prosper Ngabonziza; Martin P. Stehno; Hiroaki Myoren; Viola A. Neumann; Gertjan Koster; Alexander Brinkman
ADVANCED ELECTRONIC MATERIALS,
巻：2,
号：8, 2016年08月,
［査読有り］Combining of the ability to prepare high-quality, intrinsic Bi2Te3 topological insulator thin films of low carrier density with in situ protective capping, a pronounced, gate-tunable change in transport properties of Bi2Te3 thin films is demonstrated. Using a back gate, the carrier density is tuned by a factor of approximate to 7 in an Al2O3 capped Bi2Te3 sample and by a factor of approximate to 2 in Te capped Bi2Te3 films. Full depletion of bulk carriers is achieved, which allows access to the topological transport regime dominated by surface state conduction. When the Fermi level is placed in the bulk band gap, the presence of two coherent conduction channels associated with the two decoupled surfaces is observed. The magnetotransport results show that the combination of capping layers and electrostatic tuning of the Fermi level provide a technological platform to investigate the topological properties of surface states in transport experiments and pave the way toward the implementation of a variety of topological quantum devices.
WILEY-BLACKWELL, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1002/aelm.201600157DOI ID：10.1002/aelm.201600157,
ISSN：2199-160X,
Web of Science ID：WOS:000384454800010 Superconductor/Ferromagnet Nanowires for Optical Photon Detection R. Cristiano; L. Parlato; U. Nasti; M. Ejrnaes; H. Myoren; T. Taino; R. Sobolewski; G. P. Pepe
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：26,
号：3, 2016年04月,
［査読有り］During the last decade, research on nanowires as superconducting single-photon detectors (SNSPDs or SSPDs) has gained interest due to many experiments demonstrating their fascinating potentialities in several fields. The search for more appealing materials for SNSPDs is presently a hot topic. Several superconductors have been proposed as possible alternatives to NbN, which is presently the racehorse. Examples are WSi and MoSi, which have advantages such as amorphous morphology and narrow-gap and low quasi-particle diffusivity, which permits extending the application in the mid- and far-IR ranges. A strategy based on material hybridization of superconductors with ferromagnets can open a new direction in the development of SNSPD. We present results concerning the hybrid superconducting/ferromagnetic (S/F) single nanowires for SNSPDs. Experiments under laser illumination show a single-photon response of S/Fbased nanowires. The ferromagnetic overlayer has the beneficial effect of an increase of the superconducting critical current density and a decrease of dark counts. We compare dark counts in hybrid S/F with pure S nanowires. The experimental results are explained in terms of the existing models based on the presence of magnetic vortices.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2016.2521579DOI ID：10.1109/TASC.2016.2521579,
ISSN：1051-8223,
eISSN：1558-2515,
Web of Science ID：WOS:000372782800001 Dual-Double Slot Antennas Fabricated with Single Superconducting Film for Millimeter Wave Camera Masato Naruse; Tom Nitta; Kenichi Karatsu; Msakazu Sekine; Shigeyuki Sekiguchi; Yutaro Sekimoto; Takashi Noguchi; Tohru Taino; Hiroaki Myoren
JOURNAL OF INFRARED MILLIMETER AND TERAHERTZ WAVES,
巻：37,
号：2,
開始ページ：128,
終了ページ：136, 2016年02月,
［査読有り］We propose an entirely plane-structure camera for millimeter wave astronomy, in order to reduce production cost and time. The camera is composed of a silicon lens-let, antennas, feed lines, and detectors made from the same superconducting aluminum film on a silicon substrate. A couple of double-slot antennas are located the same focal plane of a small substrate lens to enhance the packing density of detectors and observation efficiency. To achieve high sensitivity, we adapted a microwave kinetic inductance detector as a photon sensor, which consists of a superconducting microresonator. We examined the optical performance of the camera attached to a silicon lens array at 220 GHz in a 0.3 K cryostat. The measured beams were in good agreement with the calculations within the dynamic range of the setup (20 dB). Polarization misalignments between the dual-double slot antenna were less than 2(a similar to), and cross-polarization level was around -7 dB. The relatively high cross-polarization would be explained by an antenna crosstalk mediated by quasiparticle diffusion.
SPRINGER, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1007/s10762-015-0216-yDOI ID：10.1007/s10762-015-0216-y,
ISSN：1866-6892,
eISSN：1866-6906,
Web of Science ID：WOS:000368053700002 Thermal fluctuations in superconductor/ferromagnet nanostripes U. Nasti; L. Parlato; M. Ejrnaes; R. Cristiano; T. Taino; H. Myoren; Roman Sobolewski; G. Pepe
PHYSICAL REVIEW B,
巻：92,
号：1, 2015年07月,
［査読有り］Thermal fluctuations in hybrid superconductor/ferromagnetic NbN/NiCu bilayers, as well as in pure superconducting NbN, two-dimensional (2D), nanostripes, have been investigated in order to understand the origin of dark counts in superconducting nanostripes when operated as single-photon detectors in the temperature range from 4.2 to 8 K. In 2D superconductors, the dynamics of vortex motion play a significant role in the formation of a transient normal state, leading to dark-count events in current-biased nanostripes. By introducing a weak ferromagnetic overlayer on top of pure NbN, we managed to control the vortex dynamics, which subsequently enabled us to differentiate between several proposed theoretical models. In particular, a 6 - nm - thick NiCu film grown on top of 8 - nm - thick NbN nanostripes led to an enhanced critical current density in the resulting nanostructure, as well as significantly lowered fluctuation rates, as compared to pure NbN structures, leading to reduced dark counts. The enhancement of pinning in NbN/NiCu bilayers provided evidence that thermal excitations of single vortices (vortex hopping) near the edge of a 2D nanostripe were the dominant mechanism of the observed dark-count transients. On the other hand, in pure NbN the leading source of thermal fluctuations was the current-assisted thermal unbinding of vortex-antivortex pairs.
AMER PHYSICAL SOC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1103/PhysRevB.92.014501DOI ID：10.1103/PhysRevB.92.014501,
ISSN：1098-0121,
eISSN：1550-235X,
Web of Science ID：WOS:000357484100007 Single-Flux Quantum Readout Circuits for Photon-Number-Resolving Superconducting Nanowire Single-Photon Detectors Hiroaki Myoren; Shunsuke Takeda; Masato Naruse; Tohru Taino; Jian Chen; Peiheng Wu
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：25,
号：3, 2015年06月,
［査読有り］Superconducting nanowire single-photon detectors (SNSPDs) with series-parallel meander-type configurations are demonstrated to have photon-number-resolving capabilities and are expected to be used for an evaluation system of single-photon generators and/or an energy-resolved fast detector for a new-generation time-of-flight mass spectrometry. In this paper, we present the design, fabrication, and confirmation of correct operations of two kinds of single-flux-quantum (SFQ) digital readout circuits for an SNSPD with a series-parallel meander-type configuration. Assuming a six-parallel meander-type configuration, we designed: 1) a six-level current discriminator using six different magnetically coupled DC/SFQ converter circuits; and 2) a Delta-type A/D converter using a quasi-one-junction SQUID (QOS) comparator with an SFQ feedback loop. For the design of the magnetically coupled inputs, we used a 3-D inductance extraction program FastHenry and the designed circuits were fabricated using a HYPRES 4.5-kA/cm(2) Nb process and a National Institute of Advanced Industrial Science and Technology (AIST) standard 2.5-kA/cm(2) Nb process.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2014.2365356DOI ID：10.1109/TASC.2014.2365356,
ISSN：1051-8223,
eISSN：1558-2515,
Web of Science ID：WOS:000384888700001 Design and Performance of Digital SQUID with Sub-Flux Quantum Resolution
Hiroaki Myoren; Kouhei Takatoku; Masato Naruse; Tohru Taino
2015 15TH INTERNATIONAL SUPERCONDUCTIVE ELECTRONICS CONFERENCE (ISEC), 2015年, ［査読有り］
Digital SQUIDs based on the single flux quantum (SFQ) logic have attractive characteristics, such as wide dynamic range and high slew rate. However, the resolution of digital SQUIDs is limited to SFQ. To realize sub-flux quantum resolution for these SQUIDs, we have adopted two types of feedback combinations: one with the SFQ input/output for a main loop and the other with a mutually coupled loop. The main loop receives direct Phi(0) feedback and sub-flux quantum feedback Phi(0)/n, where n is an integer, from the mutually coupled loop. We confirmed the correct operation of our device at a clock frequency of 1.25 GHz for a digital SQUID with a sub-Phi(0) flux feedback resolution of Phi(0)/8 from circuit simulation. The slew rate is found to be 1.56x10(8) Phi(0)/s in this simulation (f(c) = 1.25 GHz, n=8). The flux resolution for the digital SQUID shows improvement with increasing n and reached below 40 m Phi(0) with n=2(10); however the slew rate is decreased with increasing n and reached 1.22x10(6) Phi(0)/s with f(c)=1.25 GHz and n=2(10).
IEEE, 英語, 研究論文（国際会議プロシーディングス）
Web of Science ID：WOS:000380391200018
SFQ Amplified Circuit for Photon-Number-Resolving SNSPD Array
Kazuki Ota; Masato Naruse; Tohru Taino; Hiroaki Myoren; Jian Chen; Lin Kang; Peiheng Wu
2015 15TH INTERNATIONAL SUPERCONDUCTIVE ELECTRONICS CONFERENCE (ISEC), 2015年, ［査読有り］
Superconducting nanowire single-photon detectors (SNSPDs) with series-parallel meander-type configuration are demonstrated to have photon-number-resolving (PNR) capabilities. Based on this unique feature, SNSPDs are expected to be used in the evaluation of single photon sources. However, increasing the number of SNSPDs causes an increase in the heat flow and further degradation in the timing jitter. To resolve this problem, the use of single flux quantum (SFQ) logic circuits is proposed. In this study, we present the read-out circuit for the SNSPD array, based on the SFQ logic. Our design of the read-out circuit makes it feasible to simultaneously process six SNSPD signals at 500 MHz and amplify the output voltage as an input to other circuits without the need for any amplifiers. We confirm using simulations that our designed read-out circuit has these capabilities. Furthermore, it is shown that the output voltage increases by 4.8 mV, proportional to the number of SNSPD signals and the output voltage is between 4.8 and 27.8 mV.
IEEE, 英語, 研究論文（国際会議プロシーディングス）
Web of Science ID：WOS:000380391200053
Optical Efficiencies of Lens-Antenna Coupled Kinetic Inductance Detectors at 220 GHz Masato Naruse; Yutaro Sekimoto; Takashi Noguchi; Akihira Miyachi; Kenichi Karatsu; Tom Nitta; Masakazu Sekine; Yoshinori Uzawa; Tohru Taino; Hiroaki Myoren
IEEE TRANSACTIONS ON TERAHERTZ SCIENCE AND TECHNOLOGY,
巻：3,
号：2,
開始ページ：180,
終了ページ：186, 2013年03月
We have been developing a terahertz camera based on antenna-coupled superconducting resonators, the so-called microwave kinetic inductance detectors (MKIDs), and a silicon lens array. The MKID consists of a coplanar waveguide coupled to a double slot antenna and is patterned on a high-quality aluminum film grown by molecular beam epitaxy. The camera is sensitive at frequencies of 200-240 GHz. Its bandwidth is limited by the impedance properties of the double slot antenna. The design, fabrication, and optical evaluations of the planar antennas and silicon lens arrays are presented in this paper. The MKID camera has been evaluated both in dark conditions and under optical radiation in a 0.1-K dilution refrigerator. The electrical noise equivalent power was around 5x10(-18)W/root HZ in dark conditions and 4x10(-16)W/root HZ, which is much lower than the photon noise level, with the optical load. The optical efficiency of the camera was estimated by three independent methods, and the results were consistent with each other and equal to 20%-25% without an anti-reflection coating on the lens surface.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TTHZ.2012.2237029DOI ID：10.1109/TTHZ.2012.2237029,
ISSN：2156-342X,
eISSN：2156-3446,
Web of Science ID：WOS:000318770300010 Performance of superconducting single-photon detectors using NbN/NiCu nanowires H. Myoren; S. Taguchi; K. Ohshima; T. Wakatsuki; T. Taino; L. Parlato; G. P. Pepe
IEEE Transactions on Applied Superconductivity,
巻：23,
号：3, 2013年,
［査読有り］We present optical properties of nanowires consisting of both proximitized superconductor/ferromagnet bilayers of NbN/NiCu and pure superconducting NbN layers. Thin NbN/NiCu hetero-structures were deposited on MgO(100) substrates by in situ dc magnetron sputtering, while nanowires were patterned using standard electron beam lithography and reactive ion etching. Photo-response signals were recorded from 100-nm-wide, three-parallel and six-series NbN(8 nm)/NiCu nanowires by 850-nm pulsed laser irradiation (time width 400 ps, repetition rate ∼100 MHz). For the latter configuration the fall time of voltage responses was found to be close to 1.7 ns, and it gradually increased with increasing the NiCu film thickness. Moreover, three discrete families of photo-response signals recorded for the three-parallel and six-series nanowires were also observed. © 2002-2011 IEEE.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2013.2252344DOI ID：10.1109/TASC.2013.2252344,
ISSN：1051-8223,
SCOPUS ID：84876135686 SFQ Digital Signal Processing Circuits for Multi-Quantum Beam Detectors using STJ Array with Neutron Absorbers
Hiroaki Myoren; Yuta Akamatsu; Ryo Sasaki; Shoji Sato; Masato Naruse; Tohru Taino
2013 IEEE 14TH INTERNATIONAL SUPERCONDUCTIVE ELECTRONICS CONFERENCE (ISEC), 2013年, ［査読有り］
We studied multi-quantum beam detectors using a superconducting tunnel junction (STJ) array with neutron absorbers. Using a neutron absorber for each of the STJs, we expected the STJ detector to exhibit a high spatial resolution and high detection efficiency for neutrons as well as radiative beams such as X-rays. To obtain diffraction patterns of the Xray and neutrons, we propose the use of a multi-quantum beam detector using an STJ array and single flux quantum (SFQ) signal processing at low temperature because of its high-speed and low-power operation. The kinetic energy is determined for individual neutrons using time-of-flight-methods that employ SFQ time-to-digital converters (TDCs). To separately detect alpha-particles and gamma-ray particles that are produced by the nuclear reaction between neutrons and boron, and X-ray photons, excess quasi-particle currents of the STJ detectors are processed by V/F type analog-to-digital converters and T-FF binary counters using SFQ digital circuits. To obtain the multiplexed readout of an STJ detector array, we designed a current bias switching circuit controlled by an SFQ driver for time-domain multiplexing. We designed the main circuits for this SFQ signal processing system and fabricated them using the ISTEC SRL Nb standard process II (STP2).
IEEE, 英語, 研究論文（国際会議プロシーディングス）
Web of Science ID：WOS:000333277300034
Design of Digital DROS for Wide Dynamic Operation Range with sub-single flux quantum resolution Hiroaki Myoren; Kohsuke Terui; Naoya Shimada; Tohru Taino
SUPERCONDUCTIVITY CENTENNIAL CONFERENCE 2011,
巻：36,
開始ページ：121,
終了ページ：126, 2012年,
［査読有り］We designed a digital double relaxation oscillation SQUID (DROS) with an single flux quantum (SFQ) feedback circuit for digital SQUID magnetometers. The DROS is magneticall coupled to a feedback SQUID loop and a signal magnetic flux is input to the feedback SQUID loop. The DROS generates two kinds of voltage pulses corresponding to the total magnetic flux in the feedback SQUID loop. Those voltage pulses are converted to SFQ and anti-SFQ pulses and input to the feedback SQUID loop to keep the magnetic flux in the feedback SQUID loop constant. A read-out dc SQUID (R/O SQUID) is also magnetically coupled to the feedback SQUID loop for monitoring the actual magnetic flux in the feedback SQUID loop. The number of the generated SFQ pulses is estimated by SFQ feedback steps on output voltage curves generated from the R/O SQUID. Wide dynamic operation range is realized by the SFQ feedback and sub-Phi(0) magnetic flux resolution is realized by the R/O SQUID, where Phi(0)(= h/2e) is the single magnetic flux quantum. Also one digital DROS magnetometer can be operated with less than 10 mA. We fabricated a designed digital DROS using ISTEC SRL 2.5 kA/cm(2) Nb standard process II and are trying to confirm the correct operation of the digital DROS. (C) 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of the Guest Editors.
ELSEVIER SCIENCE BV, 英語, 研究論文（国際会議プロシーディングス）
DOI：https://doi.org/10.1016/j.phpro.2012.06.057DOI ID：10.1016/j.phpro.2012.06.057,
ISSN：1875-3892,
Web of Science ID：WOS:000314403400022 Design of Digital DROS With SFQ Up/Down Counter for Wide Dynamic Operation Range Hiroaki Myoren; Yun Kimimoto; Kosuke Terui; Tohru Taino
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：21,
号：3,
開始ページ：387,
終了ページ：390, 2011年06月,
［査読有り］We designed a digital double relaxation oscillation SQUID (DROS) with an SFQ up/down counter. The DROS is connected to a feedback SQUID loop and a signal magnetic flux is input to the feedback SQUID loop. The DROS generates two kinds of voltage pulses corresponding to the total magnetic flux in the feedback SQUID loop. Two kind of voltage pulses are converted to SFQ and anti-SFQ pulses and input to the feedback SQUID loop to keep the magnetic flux in the SQUID loop constant. The number of the generated SFQ pulses is counted using the SFQ up/down counter. Thus, the count corresponds to the input magnetic flux. Because the SFQ up/down counter is operated in the pulse driven mode, the digital DROS needs only dc bias current for operation. We designed and fabricated a digital DROS with a relaxation oscillation frequency of 3 GHz and an 8-bit SFQ up/down counter. Numerical simulation suggested the designed digital DROS has a dynamic range exceeding +/- 100 Phi(0) and magnetic flux slew rate of 3 x 10(9) Phi(0)/s.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2010.2100800DOI ID：10.1109/TASC.2010.2100800,
ISSN：1051-8223,
Web of Science ID：WOS:000291050500068 Strong critical current density enhancement in NiCu/NbN superconducting nanostripes for optical detection N. Marrocco; G. P. Pepe; A. Capretti; L. Parlato; V. Pagliarulo; G. Peluso; A. Barone; R. Cristiano; M. Ejrnaes; A. Casaburi; N. Kashiwazaki; T. Taino; H. Myoren; Roman Sobolewski
APPLIED PHYSICS LETTERS,
巻：97,
号：9, 2010年08月,
［査読有り］We present measurements of ferromagnet/superconductor (NiCu/NbN) and plain superconducting (NbN) nanostripes with the linewidth ranging from 150 to 300 nm. The NiCu (3 nm)/NbN (8 nm) bilayers, as compared to NbN (8 nm), showed a up to six times increase in their critical current density, reaching at 4.2 K the values of 5.5 MA/cm(2) for a 150 nm wide nanostripe meander and 12.1 MA/cm(2) for a 300 nm one. We also observed six-time sensitivity enhancement when. the 150 nm wide NiCu/NbN nanostripe was used as an optical detector. The strong critical current enhancement is explained by the vortex pinning strength and density increase in NiCu/NbN bilayers and confirmed by approximately tenfold increase in the vortex polarizability factor. (C) 2010 American Institute of Physics. [doi:10.1063/1.3479529]
AMER INST PHYSICS, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1063/1.3479529DOI ID：10.1063/1.3479529,
ISSN：0003-6951,
Web of Science ID：WOS:000282187200042 Photoresponse experiments on NbN proximized nanostructures G. P. Pepe; L. Parlato; V. Pagliarulo; N. Marrocco; C. De Lisio; G. Peluso; A. Barone; T. Taino; H. Myoren; A. Casaburi; M. Ejrnaes; R. Cristiano
9TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS 09),
巻：234, 2010年,
［査読有り］Among superconducting materials used in developing high performance nanowire detectors, NbN demonstrated to have unique characteristics in terms of fast response time, quantum efficiency and photon-number resolving capability. We investigated the role of proximity effect on superconducting NbN thin films covered by a weak ferromagnetic NiCu thin layer. Hetero-structures NbN/NiCu have been deposited by DC magnetron sputtering on MgO substrates without any heating. Characterization in terms of morphological, transport, and ultra-fast optical properties has been done. Superconducting nanowires with meander-type geometries (48 micron lengths and <500 nm widths) have been designed and fabricated. Preliminary results concerning their photoresponse to 1550nm laser irradiation are presented.
IOP PUBLISHING LTD, 英語, 研究論文（国際会議プロシーディングス）
DOI：https://doi.org/10.1088/1742-6596/234/4/042027DOI ID：10.1088/1742-6596/234/4/042027,
ISSN：1742-6588,
Web of Science ID：WOS:000304593700192 SFQ Multiplexed Signal Processing Circuits for STJ Photon Detector Arrays Hiroaki Myoren; Yu Yoshizawa; Tohru Taino
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：19,
号：3,
開始ページ：413,
終了ページ：416, 2009年06月,
［査読有り］We have been studying single flux quantum (SFQ) digital signal processing (DSP) circuits for superconducting tunnel junction (STJ) photon detector arrays. The proposed DSP circuit consists of a binary tree of multiplexers, a time counter, a binary counter, and a readout memory. Each multiplexer was designed such that the first arriving SFQ pulse train connects to the binary counter until the time counter reaches a set value. The time counter is set to a sufficiently long time compared with the response time of STJ photon detector. After processing the multiplexer, SFQ pulses are integrated by the binary counter. The number of integrated SFQ pulses is proportional to the number of quasi-particles generated by photon irradiation in an STJ. After the time counter reaches the set value, the time counter generates a set SFQ pulse to set the multiplexer in the ready state, the integrated value is sent to the readout memory and then the binary counter is reset. The binary tree of multiplexers could be extended to have address bits for photon imaging using an STJ array. One key component of the proposed DSP circuit was fabricated and its operation using an on-chip clock generator was successfully demonstrated.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2009.2017947DOI ID：10.1109/TASC.2009.2017947,
ISSN：1051-8223,
Web of Science ID：WOS:000268282000067 Superconducting NbN Nanowire Photo Switches for Generating Single Flux Quantum Pulses Hiroaki Myoren; Yusuke Mada; Yuji Matsui; Tohru Taino; Susumu Takada
8TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'07),
巻：97, 2008年,
［査読有り］We investigated superconducting NbN nanowire as a photo switch for generating single flux quantum (SFQ) pulses. Epitaxially grown NbN thin films were prepared on MgO(100) substrates by a dc magnetron sputtering method using gas mixture of Ar + N(2), without substrate heating. NbN thin films showed Tc of 13.6 K for 8 nm, and 10 K for 4 nm. NbN nanowires were patterned using a electron beam lithography with 200 nm thick electron beam resist. To increasing photo-sensitive regions, we fabricated 50 x 50 1 m 2 meander patterns with NbN nanowires. Line width of nanowires was varied from 150 nm to 500 nm. Critical current density of NbN nanowires was about 3x10(6) A/cm(2) at 4.2 K. We irradiated 850-nm laser pulses via 50-1 m multi-mode optical fibers. Repetition frequency and pulse width could be controlled by a pulse pattern generator. The maximum laser pulse power was about 1 mW. Using 150-nm-wide NbN nanowires, half of critical current was suppressed by 1 mW CW laser irradiations. High speed responses were observed for laser pulses with repetition frequency of 1 MHz and pulse width of 2 ns. Besides the NbN nanowire photo switches, we designed an SFQ interface circuit based on Josephson transmission lines. The designed circuit could generate SFQ pulses by input current of 10 mu A, 25 GHz current pulses. Dc bias margin of the circuit was +/-15% for 60 mu A current pulses.
IOP PUBLISHING LTD, 英語, 研究論文（国際会議プロシーディングス）
DOI：https://doi.org/10.1088/1742-6596/97/1/012329DOI ID：10.1088/1742-6596/97/1/012329,
ISSN：1742-6588,
Web of Science ID：WOS:000276054100328 Terahertz electromagnetic-wave detector using Nb-based superconducting tunnel junction on LiNbO3substrate absorber T. Taino; H. Ishii; S. Yoshimura; C. Otani; S. Ariyoshi; H. Myoren; K. Kawase; T. Shibuya; H. Sato; H. M. Shimizu; S. Takada
Physica C: Superconductivity and its Applications,
巻：463-465,
開始ページ：1119,
終了ページ：1122, 2007年10月,
［査読有り］We have been developing terahertz (THz) wave detectors using superconducting tunnel junctions (STJs). The STJs consist of the Nb/Al/AlO x /Al/Nb structure. We fabricated THz-wave detectors on LiNbO 3 substrates that have a high absorption coefficient for the frequency range of 10 12 Hz. Two kinds of signals were detected when the THz-wave was irradiated from the substrate side. One was an indirect signal related to the generation of phonons. The other was a signal that corresponds to directly generated quasi-particles in the Nb electrode of the STJ. The pulse height of the indirect signal was larger than that of the latter signal. To enlarge the detector area, we designed a STJ that has different areas of the base electrode and top electrode. In this paper, the characteristics of the THz-wave detector area will be discussed. © 2007 Elsevier B.V. All rights reserved.
DOI：https://doi.org/10.1016/j.physc.2007.03.500DOI ID：10.1016/j.physc.2007.03.500,
ISSN：0921-4534,
J-Global ID：200902248422821370,
SCOPUS ID：34548454987 Minimization of parasitic inductances in SFQ circuits using over- and under-ground planes Hiroaki Myoren; Noriaki Kishita; Tohru Taino; Susumu Takada
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：17,
号：2,
開始ページ：462,
終了ページ：465, 2007年06月,
［査読有り］We designed the single-flux-quantum (SFQ) circuits that were fabricating using the NEC 2.5 kA/cm(2) standard process that has four Nb layers. Before designing circuits with two ground planes, we estimated sheet inductances, of the base and counter planes,using simple rectangular-shape inductors. Estimated sheet inductance of the base plane was 0.75 of the original value for the circuits with only under-ground plane. For the counter plane, sheet inductance was estimated to be 0.55 of the original value. We designed a 2-branch D-FF gate and fabricated SFQ circuits including the 2-branch D-FF using the NEC standard process. Parasitic inductances of the counter layer in the 2-branch D-FF were effectively minimized using two ground planes and frequency dependences of the lower bias margin were improved.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2007.898053DOI ID：10.1109/TASC.2007.898053,
ISSN：1051-8223,
Web of Science ID：WOS:000248442200090 A broadband terahertz detector using a superconducting tunnel junction T. Taino; R. Nakano; S. Yoshimura; H. Myoren; S. Takada; C. Otani; S. Ariyoshi; T. Shibuya; K. Kawase; H. Sato; H. M. Shimizu
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
巻：559,
号：2,
開始ページ：751,
終了ページ：753, 2006年04月
We have proposed and demonstrated a new broadband terahertz (THz) wave detector using a superconducting tunnel junction (STJ) fabricated on LiNbO3, LiTaO3, and sapphire substrates. These substrates have relatively high absorption efficiency for THz waves, and we have expected that incident THz waves from substrate side are absorbed and that generate many THz phonons which break Cooper pairs in the base superconductor electrode of the STJ. Using a frequency-tunable THz pulse source in 1-2 THz, we have confirmed that the current signal corresponding to the THz input was observed. In addition, we found two current components with different timescales for the first time. We interpret that the slow component corresponds to phonons absorbed with the substrate and that the fast one corresponds to the directly absorbed photons with the superconductor electrode of the STJs. © 2006 Elsevier B.V. All rights reserved.
研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.nima.2005.12.207Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=33645883838&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=33645883838&origin=inwardDOI ID：10.1016/j.nima.2005.12.207,
ISSN：0168-9002,
SCOPUS ID：33645883838 Polyimide Buffer Layer for STJ Photon Detector T. Taino; M. Yoshida; M. Narisawa; H. Myoren; K. Kikuchi; H. Nakagawa; M. Aoyagi; H. Sato; H. M. Shimizu; S. Takada
7TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'05),
巻：43,
開始ページ：1319,
終了ページ：1321, 2006年,
［査読有り］We have proposed and been developing ultra low noise photon detector using superconducting tunnel junctions (STJs). The STJs are fabricated on polyimide ( PI) layer which is prepared on sapphire substrate. The PI is coated on the substrate before making the STJ. It acts as buffer layer to suppress a great deal of phonon events which come from the substrate. For low energy application such as soft X-ray and extreme ultraviolet, the STJs with PI buffer layer is a very attractive detector because the spectrum of low energy photons can measured clearly without noise that depends on phonon events in the substrate. We fabricated the STJs with PI buffer layer which are different thickness and measured X-ray spectrum of 5.9 keV. We found that polyimide of 100 nm thickness is enough to suppress phonon events in low energy range.
IOP PUBLISHING LTD, 英語, 研究論文（国際会議プロシーディングス）
DOI：https://doi.org/10.1088/1742-6596/43/1/322DOI ID：10.1088/1742-6596/43/1/322,
ISSN：1742-6588,
Web of Science ID：WOS:000277479400322 Quasiparticles Injection Effects for Nb/Al/AlOx/Al/Nb Tunnel Junctions at 0.4K using Stacked Josephson Junctions Hiroaki Myoren; Akiko Shigihara; Tohru Taino; Susumu Takada
7TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'05),
巻：43,
開始ページ：1326,
終了ページ：1329, 2006年,
［査読有り］We have studied on the quasiparticles (QPs) injection effects for Nb/Al/AlOx/Al/Nb tunnel junctions at 0.4 K. A device structure was a stack of an injector Josephson junction (JJ) and a detector JJ. At a low temperature, there is small number of thermally excited QPs and we expected to observe easily the QPs injection effect of the detector JJ using the injector JJ. In this study, the structure of the Nb/Al/AlOx/Al/Nb tunnel junctions was the same for X-ray detectors using superconducting tunnel junctions. For constant-QPs current injection, we expected a small-signal current gain exceed the unity. We used pulsed-QPs current with changing pulse duration. For long duration, I-V curves for the detection junctions were sum of original current and QP current. On the other hands, for short duration time, the I-V curves showed different shapes from those for the long duration time.
IOP PUBLISHING LTD, 英語, 研究論文（国際会議プロシーディングス）
DOI：https://doi.org/10.1088/1742-6596/43/1/324DOI ID：10.1088/1742-6596/43/1/324,
ISSN：1742-6588,
Web of Science ID：WOS:000277479400324 Direct and Indirect Detection of Terahertz Waves using a Nb-based Superconducting Tunnel Junction Otani Chiko; Nakano Ran; Taino Tohru; Shibuya Takayuki; Ariyoshi Seiichiro; Yoshimura Shota; Myoren Hiroaki; Sato Hiromi; Shimizu Hirohiko M; Takada Susumu; Kawase Kodo
7TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'05),
巻：43,
開始ページ：1303,
終了ページ：1306, 2006年,
［査読有り］DOI：https://doi.org/10.1088/1742-6596/43/1/318DOI ID：10.1088/1742-6596/43/1/318,
ISSN：1742-6588,
Web of Science ID：WOS:000277479400318 Development of terahertz wave detector using superconducting tunnel junction T Taino; K Hoshino; R Nakano; C Otani; H Myoren; K Kawase; T Shibuya; H Sato; HM Shimizu; S Takada
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS,
巻：426,
開始ページ：1731,
終了ページ：1735, 2005年10月,
［査読有り］We have developed a new terahertz (THz) wave detector using an Nb-based superconducting tunnel junction (STJ). The STJ consists of a Nb/Al/AlOx/Al/Nb structure on a single-crystal LiNbO3 substrate. Using LiNbO3 as a substrate, an irradiating THz wave is converted to phonons in LiNbO3, which has a relatively high absorption coefficient. The phonons propagating in the substrate reach the Nb base electrode of the STJ and break Cooper pairs. As a result, the THz wave can be detected as tunneling current signals in the STJ. THz waves from a widely tunable THz-wave parametric oscillator (TPO) were irradiated on to the STJ, which acted as a THz wave detector. The STJs were cooled to an operating temperature of 0.4 K using a He-3 cryostat. We have observed STJ signals related to THz wave irradiations. In this paper, fabrication processes and characteristics of THz wave detectors using STJs are also discussed. (c) 2005 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.physc.2005.02.137DOI ID：10.1016/j.physc.2005.02.137,
ISSN：0921-4534,
Web of Science ID：WOS:000232698700153 The effect of X-ray irradiating superconducting tunnel junctions on Al2O3 and LiNbO3 substrates T Taino; K Hoshino; R Nakano; C Otani; H Myoren; K Kawase; H Sato; HM Shimizu; S Takada
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：15,
号：2,
開始ページ：599,
終了ページ：601, 2005年06月,
［査読有り］We have developed a phonon-mediated radiation detector using Nb-based superconducting tunnel junctions (STJs). The STJs are fabricated on a substrate as an absorber of the radiation, and a substantial amount of emergent phonons with an energy above the energy gap are detected. The performance of the detector depends on the collection efficiency of the phonons. A selection of an appropriate substrate is required for optimizing the detector performance. We fabricated Nb-based STJs on a Al2O3 and a LiNbO3 substrates, and compared the pulse heights of substrate phonon events due to X-ray irradiation to the substrates. We found that the maximum pulse height of the phonon events for the LiNbO3 substrate. was about twice of that for the Al2O3 substrate, so that these spectra which was obtained from two STJs showed different shapes, especially the peak due to phonon events.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2005.849953DOI ID：10.1109/TASC.2005.849953,
ISSN：1051-8223,
Web of Science ID：WOS:000229765300131 Efficient fabrication process for superconducting integrated circuits using photosensitive polyimide insulation layers K Kikuchi; M Goto; H Nakagawa; S Segawa; K Tokoro; T Taino; H Myoren; S Takada; M Aoyagi
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：15,
号：2,
開始ページ：94,
終了ページ：97, 2005年06月,
［査読有り］Photosensitive polyimide insulation layers have been introduced to fabricate superconducting integrated circuits. It is shown to simplify the fabrication process, because the photosensitive polyimide insulation layer can be patterned by conventional photolithography process, resulting in the etching process unnecessary in the present new fabrication process. Three kinds of contact hole (junction top electrode contact, junction base electrode contact, and resistor contact) are simultaneously formed in the photolithography process of the polyimide. A minimum contact hole size is designed to be 1.5 mu m square for a 3 mu m x 3 mu m squared junction. Superconducting current density of 2.4 x 10(6) A/cm(2) of the contact hole was measured. Palladium resistors were successfully made with through hole contacts of the photosensitive polyimide insulation layer. We demonstrated superconducting integrated circuits using this new fabrication process including the minimum 3 mu m x 3 mu m squared Nb/Al - AlOx/Nb Josephson tunnel junction. The circuit operation is also demonstrated in the fabricated superconducting integrated circuits with the photosensitive polyimide insulation layers.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2005.849702DOI ID：10.1109/TASC.2005.849702,
ISSN：1051-8223,
Web of Science ID：WOS:000229765300006 A broad-band THz radiation detector using a Nb-based superconducting tunnel junction C Otani; T Taino; R Nakano; K Hoshino; Shibuya, I; H Myoren; S Ariyoshi; H Sato; HM Shimizu; S Takada; K Kawase
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：15,
号：2,
開始ページ：591,
終了ページ：594, 2005年06月,
［査読有り］We have proposed and been developing a new broad-band terahertz (THz) radiation detector using a Nb-based superconducting tunnel junction (STJ). The STJ's were fabricated on LiNbO3 and LiTaO3 mono-crystal substrates. We radiated monochromatic THz pulses in the range 1-2 THz with the pulse repetition rate of 49 Hz, and successfully detected the corresponding periodic signals via a charge-sensitive preamplifier. The current signal obtained by the derivative of the output signal gave the time response of about 15-20 microseconds. The frequency response was compared with that of a conventional pyro-electric sensor. We found their frequency response showed the similar shape in frequency, demonstrating the flat response of the STJ detector in 1-2 THz. These results show that the detector can be used as a broad-band THz and far-infrared radiation detector above the frequency corresponding to the energy gap of the superconductor used for the base electrode.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2005.849950DOI ID：10.1109/TASC.2005.849950,
ISSN：1051-8223,
J-Global ID：201302272130921625,
SCOPUS ID：22044458600,
Web of Science ID：WOS:000229765300129 Array of superconducting quantum interference devices with multiturn input coil T Morooka; H Myoren; S Takada; K Chinone
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS,
巻：43,
号：5A,
開始ページ：2473,
終了ページ：2478, 2004年05月,
［査読有り］Arrays of dc-superconducting quantum interference devices (dc-SQUIDs) were investigated, in which each dc-SQUID element has a multiturn input coil. The dependence of flux noise on the number of turns of the input coil was studied for current amplifiers. SQUID arrays were fabricated by a Nb/AlOx/Nb Josephson tunnel junction fabrication process. Results show that the flux noise of the SQUID array amplifier does not depend on the turn number of the input coil. A SQUID array amplifier consisting of 128 dc-SQUID elements was fabricated, in which each element had a 7-turn input coil and a mutual inductance between the input coil and the SQUID loop of 460 pH. This amplifier showed an ultrahigh current resolution of 1 pA/Hz(0.5) and a maximum input current of 11 muA for signals of 50 kHz, which is sufficient bandwidth for X-ray detection applications. These values correspond to a large dynamic range of 87 dB. The flux-voltage characteristics of this SQUID array, however. showed asymmetric behavior, which originated from electronic resonance in stray capacitance and the mutual inductance between the SQUID loop and the multiturn input coil.
INST PURE APPLIED PHYSICS, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1143/JJAP.43.2473DOI ID：10.1143/JJAP.43.2473,
ISSN：0021-4922,
Web of Science ID：WOS:000221703600018 Design of single-flux-quantum universal gates with a wide operating margin
H Myoren; Y Wakimizu; S Takada
SUPERCONDUCTOR SCIENCE & TECHNOLOGY, 巻：16, 号：12, 開始ページ：1447, 終了ページ：1451, 2003年12月, ［査読有り］
We have successfully designed single-flux-quantum (SFQ) universal gates with a wide operating margin. We have previously presented universal gates such as NAND and NOR gates. These universal gates have a small operating margin and should be optimized to realize a wide operating margin. In this study, we newly designed universal gates and optimized the device parameters using an SFQ circuit-optimizing tool. Assuming a 1 kA cm(-2) Nb/Al-AlOx/Nb junction technology, the newly designed NAND and NOR gates had a critical margin of more than +/-20% for 20 GHz operation. Direct-current bias margins for NAND and NOR gates were also exceeded by +/-30% for 20 GHz operation.
IOP PUBLISHING LTD, 英語, 研究論文（学術雑誌）
ISSN：0953-2048, Web of Science ID：WOS:000187796500028
1 pA/root Hz amplifier using superconducting quantum interference device array T Morooka; H Myoren; S Takada; K Chinone
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS,
巻：42,
号：11B,
開始ページ：L1375,
終了ページ：L1376, 2003年11月,
［査読有り］An ultrahigh current resolution of 1 pA/rootHz was achieved by a superconducting quantum interference device (SQUID) amplifier, which consisted of 128 repeated dc-SQUID elements. Each element had a 7-turn input coil. The SQUID amplifier was fabricated, using a Nb/AlOx/Nb fabrication process. To evaluate current resolution, flux noise and flux-voltage (Phi-V) characteristics were measured at 4.2 K. The Phi-V characteristics showed a large voltage swing of more than 4 mV. The SQUID amplifier was operated at a smooth slope in the Phi-V characteristics, while asymmetric behavior appeared in the same Phi-V characteristics.
INST PURE APPLIED PHYSICS, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1143/JJAP.42.L1375DOI ID：10.1143/JJAP.42.L1375,
ISSN：0021-4922,
Web of Science ID：WOS:000187509400010 Characteristics of flux noise in long superconducting quantum interference device array T Morooka; H Myoren; S Takada; K Chinone
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS,
巻：42,
号：11,
開始ページ：6848,
終了ページ：6852, 2003年11月,
［査読有り］The flux noise in a long superconducting quantum interference device (SQUID) array consisting of at least 100 dc-SQUID elements connected in series was characterized analytically, and then compared with measurements. In the analysis, noise sources in the array were shunt resistors for Josephson junctions, a damping resistor for a SQUID loop, the dynamic resistance of the SQUID array, and the noise of electronics at room temperature. The flux noise of the array was calculated analytically as a function of the number of dc-SQUID elements. The results reveal that the flux noise is significantly influenced by the dynamic resistance of the array, although the influence by the dynamic resistance for a single SQUID is negligibly small. The dynamic resistance becomes dominant for the flux noise when the number of SQUID elements in the array exceeds 100. These results agree well with the measured flux noise for a long SQUID array constructed using a Nb/AlOx/Nb fabrication process.
INST PURE APPLIED PHYSICS, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1143/JJAP.42.6848DOI ID：10.1143/JJAP.42.6848,
ISSN：0021-4922,
Web of Science ID：WOS:000187509000025 Nb-based superconducting tunnel junctions with beta-Ta trapping layers for photon detectors H Myoren; Y Kogure; S Takada; H Sato; C Otani; HM Shimizu; K Maehata
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY,
巻：13,
号：2,
開始ページ：1136,
終了ページ：1138, 2003年06月,
［査読有り］We have successfully fabricated Nb-based superconducting tunnel junctions (STJs) with beta-Ta trapping layers. In an Nb/beta-Ta stacked structure, beta-Ta film showed the thickness dependence of critical temperature T-c in current-voltage (I-V) characteristics due to the proximity effect from Nb films. We fabricated Nb-based STJs with beta-Ta trapping layers for X-ray detector working at 0.4 K. We obtained an energy resolution of 52 eV for 5.9 keV X-ray irradiation at 0.4 K. We expect a high energy resolution by optimizing the thickness of beta-Ta trapping layers and improving the fabrication process.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TASC.2003.814174DOI ID：10.1109/TASC.2003.814174,
ISSN：1051-8223,
Web of Science ID：WOS:000184241700264 Design of a 4 x 4 Banyan network switch with a dual-buffer structure using SFQ logic circuits
J Takahashi; H Myoren; S Takada
IEICE TRANSACTIONS ON ELECTRONICS, 巻：E86C, 号：1, 開始ページ：9, 終了ページ：15, 2003年01月, ［査読有り］
We have designed a 4 x 4 Banyan switch using SFQ logic circuits. The switch is composed of three parts; one is an input buffer, the second is a contention solver which checks packet contention in a distribution network, and the third is a packet distribution network which distributes contention-free packets to their destination address. The packet distribution network is composed of Batcher-Banyan switch with the input buffer. The contention solver decides to send a data packet to the distribution network, using only internal routing tags which are added to packets in the switch. As the circuit is composed of two parts, the contention solver and the packet distribution network, the transfer rate is raised because it doesn't need to wait any more while a data packet passes through the distribution network. Simulation results using JSIM show that the switch circuit can operate at a clock frequency of 40 GHz.
IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 英語, 研究論文（学術雑誌）
ISSN：0916-8524, eISSN：1745-1353, Web of Science ID：WOS:000180489800003
Fiske steps of Josephson tunnel junctions formed with normal-distribution function K Kikuchi; H Myoren; T Iizuka; S Takada
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS,
巻：41,
号：8,
開始ページ：5131,
終了ページ：5134, 2002年08月,
［査読有り］Magnetic field dependence of Fiske steps has been investigated using Nb/Al-AlOx/Nb tunnel junctions formed with a normal-distribution function with a dispersion parameter of sigma = 0.45. Fiske steps are due to the different resonance mode appearing in the current-voltage characteristics when an external magnetic field is applied to the junctions at 4.2 K. Both positions in the voltage scale and current amplitude of Fiske steps were systematically measured. We found that the amplitudes of the Fiske steps increased gradually, and then decreased monotonically with an increase in magnetic field. All Fiske steps almost completely disappeared at a magnetic field of less than I mT, at which the dc Josephson critical current also decreased to less than 10(-3) of the maximum. The position of Fiske steps in the voltage scale was analyzed using a diamond-shaped junction which corresponds to a 45-degree-rotated square junction.
INST PURE APPLIED PHYSICS, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1143/JJAP.41.5131DOI ID：10.1143/JJAP.41.5131,
ISSN：0021-4922,
Web of Science ID：WOS:000180071800025 Normal distribution function shaped superconducting tunnel junctions with Ta electrodes
H Myoren; Y Kogure; A Abe; K Kikuchi; T Iizuka; S Takada
PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS, 巻：372, 開始ページ：395, 終了ページ：398, 2002年08月, ［査読有り］
We prepared normal distribution function shaped (NDF-shaped) superconducting tunnel junctions (STJs) with Ta electrodes. Using two different phases of Ta, we successfully prepared STJs with bcc-Ta and beta-Ta electrodes. The critical current of the NDF-shaped STJs with Ta electrodes showed an exponential decrease for the applied magnetic field. We determined the coherence length for bcc-Ta and beta-Ta combined with Nb at 0.4 K. Coherence lengths were determined to be 21 nm for bcc-Ta and 16 nm for beta-Ta combined with Nb. For the quasiparticle trapping and amplification, beta-Ta is expected to be a good electrode combined with Nb because of the short coherence length. (C) 2002 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0921-4534, Web of Science ID：WOS:000177936400096
Properties of NbTiN thin films prepared by reactive DC magnetron sputtering
H Myoren; T Shimizu; T Iizuka; S Takada
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, 巻：11, 号：1, 開始ページ：3828, 終了ページ：3831, 2001年03月, ［査読有り］
We have prepared Nb1-xTixN (NbTiN) thin Rims by reactive de magnetron sputtering without intentional heating. Superconducting properties were strongly related to sputtering conditions. Lattice parameters of NbTiN Alms approached that of bulk NbTiN with decreasing the N-2 mole fraction in Ar and Nz sputtering gas mixture. The film orientation was also strongly related with the sputtering conditions such as gas pressure. NbN thin Alms could grow epitaxially on MgO(100) substrates and showed very smooth surfaces. We found that smooth NbTiN films could be obtained on MgO(100) substrates with epitaxially grown NbN template layer.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
ISSN：1051-8223, Web of Science ID：WOS:000168285900283
Sidelobes suppression in normal-distribution-shaped Josephson tunnel junctions
K Kikuchi; H Myoren; T Iizuka; S Takada
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, 巻：11, 号：1, 開始ページ：855, 終了ページ：858, 2001年03月, ［査読有り］
We have studied normal-distribution-shaped Josephson tunnel junctions for STJ (superconducting tunnel junction) photon detector applications. By employing a normal-distribution function to the shape of the superconducting electrodes sidelobes of the Josephson current were entirely suppressed wits a small magnetic field. This behavior was confirmed experimentally by using Nb/AlOx/Nb Josephson tunnel junctions. There were no oscillatory sidelobes in the Josephson current dependence on the magnetic field. Experimental results were in good agreement with theoretical ones. The Josephson current was efficiently suppressed by an external magnetic field of about 0.5 mT at 4.2 K, which is less than one tenth that of other shaped junctions. In the experiment at 0.3 K, Fiske step due to the resonances were not observed by suppression wits a magnetic field of about 1 mT.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
ISSN：1051-8223, Web of Science ID：WOS:000168285400198
Proposal of a digital double relaxation oscillation SQUID
H Myoren; M Nakamura; T Iizuka; S Takada
IEICE TRANSACTIONS ON ELECTRONICS, 巻：E84C, 号：1, 開始ページ：49, 終了ページ：54, 2001年01月, ［査読有り］
We present a digital double relaxation oscillation SQUID (DROS) with a digital flux-locked-loop (FLL) circuit consisting of an up/down counter and a digital-to-analog (D/A) converter. The up/down counter was: designed using 4 junction logic (4JL) gates operated with a 2-phase power system. The D/A converter was: designed using an R-2R ladder-type D/A converter. We simulated the dynamic behavior of the digital DROS with a digital FLL circuit combined with the 5-bit ripple up/down counter and the D/V converter. Simulation results show correct flux-locked behavior and a high slew rate of 10(7)phi (0)/s for the digital DROS.
IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 英語, 研究論文（学術雑誌）
ISSN：0916-8524, eISSN：1745-1353, Web of Science ID：WOS:000166624700009
Suppression of the Josephson current in normal-distribution-shaped tunnel junctions
K Kikuchi; H Myoren; T Iizuka; S Takada
JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS, 巻：39, 号：10, 開始ページ：5828, 終了ページ：5831, 2000年10月, ［査読有り］
The magnetic field dependence of the Josephson current of a Josephson tunnel junction whose shape was a normal distribution is analyzed for superconducting tunnel junction (STJ) photon detector applications. It was found that the Josephson current of a normal distribution junction is very sensitive to the external magnetic field and follows a function of exp(-B-2), while a conventional rectangular STJ exhibits the well-known Fraunhofer pattern of sin x/x. Numerical calculations show that the Josephson current of the normal distribution junction fan be suppressed by an external magnetic field that is one tenth of that needed for conventional rectangular junctions. Calculations of a normal distribution junction approximated with a 1 mum mesh also show that the Josephson current is sufficiently suppressed by a small magnetic field. The effect of the misalignment of the angle between the junction and the magnetic field was evaluated. It was found that for a normal-distribution-shaped junction, misalignment of the magnetic field is allowed within +/-5 degrees, suppressing the Josephson effect by two orders of magnitude more than that of a rectangular junction.
INST PURE APPLIED PHYSICS, 英語, 研究論文（学術雑誌）
ISSN：0021-4922, Web of Science ID：WOS:000090139000021
NAND gate for SFQ logic circuits
H Myoren; S Ono; S Takada
IEICE TRANSACTIONS ON ELECTRONICS, 巻：E83C, 号：1, 開始ページ：81, 終了ページ：84, 2000年01月, ［査読有り］
We propose a universal NAND logic gate based on single flux quantum (SFQ) logic. The NAND gate enables the construction of any logic circuits. In the proposed gate, three superconducting loops share two Josephson junctions (JJs). The critical currents of the JJs were designed to allow each of any two loops to trap an SFQ at the same time. We simulated dynamic operation of this NAND gate. The results show that the NAND gate carl operate with a delay time of 45 ps, and the power consumption of this circuit is close to 0.06 mu W/gate.
IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG, 英語, 研究論文（学術雑誌）
ISSN：0916-8524, eISSN：1745-1353, Web of Science ID：WOS:000084974300013
Mm and sub-mm properties of ramp-type Josephson junctions on MgO with STO buffer layers
H Myoren; J Chen; T Yamashita; L Amatuni; AH Sonnenberg; GJ Gerritsma; H Rogalla
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, 巻：9, 号：2, 開始ページ：3854, 終了ページ：3857, 1999年06月, ［査読有り］
We have successfully fabricated ramp-type junctions on MgO substrates using an SrTiO3 (STO) buffer layer. The observed IcRn product for the junctions on MgO with STO buffer layer were about 2mV at 4.2K and 0.1mV at 60K. The junctions clearly showed Shapiro steps under irradiation of mm-waves and sub-mm-waves. We observed Josephson emission at 50GHz from a junction on a MgO substrate with STO buffer layer at 17K. We have also confirmed mixing in the self-oscillating mode using mm-wave and sub-mm-wave signals.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
ISSN：1051-8223, Web of Science ID：WOS:000081964500248
Fabrication of Josephson junctions on La-Sr-Cu-O single crystals
Y Uematsu; H Myoren; K Nakajima; T Yamashita; Tanaka, I; H Kojima
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, 巻：9, 号：2, 開始ページ：4296, 終了ページ：4299, 1999年06月, ［査読有り］
We have successfully fabricated Josephson junctions on single crystals of La2-xSrxCuO4 (LSCO) high - T-c superconductor using niobium (Nb) as counter electrodes. A reproducible fabrication process has been established taking into account the surface state of LSCO is dominantly affecting junction properties. The surface state of LSCO has been characterized using SPS. The current voltage curves (IVCs) of Nb/LSCO junctions exhibit RSJ like Josephson junction properties. Due to intrinsic Josephson effect of LSCO, the IVCs branches are first observed for the Nb/LSCO junctions on LSCO mesa whose interfaces are parallel to the ab-plane of LSCO.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
ISSN：1051-8223, Web of Science ID：WOS:000081964500355
Variation of LaSrCuO film temperature during pulsed laser deposition on LaSrGaO substrate
C Buzea; H Myoren; HB Wang; K Nakajima; T Yamashita
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, 巻：9, 号：2, 開始ページ：2398, 終了ページ：2401, 1999年06月, ［査読有り］
By using a conventional laser ablation system, LSCO thin films were deposited on LaSrGaO4(100) substrates in an oxygen environment. During deposition the temperature of the film surface was measured with an infrared pyrometer. The measured temperature decreases following the exponential law of radiation absorption in a material. The experimental results indicate an increase of the deviation from the exponential law with decreasing oxygen pressure in the chamber. The conclusion of this experiment reveals the fact that either the refraction index of the deposited material may vary non-uniformly or the deposition velocity is not a constant during laser ablation.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
ISSN：1051-8223, Web of Science ID：WOS:000081964300245
High-Tc ramp-type Josephson junctions on MgO substrates for terahertz applications
H Myoren; MAJ Verhoeven; J Chen; K Nakajima; T Yamashita; DHA Blank; H Rogalla
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, 巻：8, 号：3, 開始ページ：132, 終了ページ：136, 1998年09月, ［査読有り］
The authors successfully fabricated high-if, ramp-type junctions with PrBa2Cu3-xGa2O7-delta (PBCGO: x = 0.1, 0.4) barriers on MgO substrates, The junctions showed resistively shunted Josephson junction (RSJ)-like I-V curves with thermally and voltage activated conductivity. The IcRn products for these junctions scaled very well with the Ga-doping, Maximum response of the junctions for 100-GHz millimeter-wave irradiation could be observed up to 12 mV corresponding to 6 THz, Using far infrared laser radiation, we confirmed a terahertz (THz) response of these junctions. These results show promise for THz-wave applications of ramp-type Josephson junctions.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
ISSN：1051-8223, Web of Science ID：WOS:000075853000005
Electric Field Effects on YBa2Cu3O7-δ Grain Boundary Josephson Junctions Nakajima Kensuke; Yokota Kazuki; Chen Jian; Myoren Hiroaki; Yamashita Tsutomu
Jpn J Appl Phys,
巻：33,
号：7,
開始ページ：L934,
終了ページ：L937, 1994年07月
Various effects of the electric field on YBa2Cu3O7-δ grain boundary Josephson junctions were studied using inverted metal-insulator-superconductor (MIS) samples which employed bicrystal SrTiO3 substrates as insulators. The critical cutrents, I c of the junctions were regulated by gate voltages with the field-induced changes in charge carrier densities. Furthermore, a significant field effect on equidistant step structures observed in I-V curves was found. The equidistant steps can be ascribed to self-resonances of the ac Josephson current in the grain boundary junctions. The gate voltages shifted the step voltages corresponding to resonance frequencies of the grain boundary toward high voltages. This appears to be a consequence of the field dependence of dielectric properties of grain boundary junctions.
社団法人応用物理学会, 英語
DOI：https://doi.org/10.1143/JJAP.33.L934DOI ID：10.1143/JJAP.33.L934,
ISSN：0021-4922,
CiNii Articles ID：110003921915,
CiNii Books ID：AA10650595 YBCO ARTIFICIAL GRAN BOUNDARY JUNCTIONS ON Si
J. Chen; T. Yamashita; H. Suzuki; H. Myoren; K. Nakajima; Y. Osaka
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY, 巻：3, 号：1, 開始ページ：2333, 終了ページ：2336, 1993年03月, ［査読有り］
Si bicrystal substrates with different misorientation angles were fabricated using the hot-press method and their qualities were examined by SEM, TEM and XRD. YBa2Cu3O7-delta(YBCO) epitaxial thin films were grown on such substrates by rf magnetron sputtering, with yttria (Y2O3) and yttria-stabilized zirconia(YSZ) as the buffer layers. The properties of bridge type junctions patterned on the film by an excimer laser were studied from 4.2K to 77K It was found that the critical current density of the artificial grain boundary(AGB) junction (J(C)A) was always less than that of the junction made on Si single-crystal grains (J(C)G). The ratio J(C)A/J(C)G decreased exponentially as the misorientation angle(theta) was increased. The effect of temperature and microwave irradiation showed that the properties of AGB junctions with theta<5 degrees were limited by flux creep. In contrast, AGB junctions with theta >= 10 degrees showed the Josephson effect. Clear Shapiro steps and Josephson mixing were observed at 77K.
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 英語, 研究論文（学術雑誌）
ISSN：1051-8223, eISSN：1558-2515, Web of Science ID：WOS:000209703300130
エアブリッジ構造を有する力学インダクタンス検出器によるα線検出
五十嵐洋介; 成瀬雅人; 田井野徹; 明連広昭
応用物理学会秋季学術講演会講演予稿集(CD-ROM), 巻：83rd, 2022年
ISSN：2758-4704, J-Global ID：202302252005973677
異なる線路幅を有する超伝導マイクロ共振器のアルファ線に対するエネルギー分解能評価 (超伝導エレクトロニクス)
安藤 友彦; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：119, 号：369, 開始ページ：151, 終了ページ：153, 2020年01月16日
電子情報通信学会, 英語
ISSN：0913-5685, CiNii Articles ID：40022155941, CiNii Books ID：AN10012885
超伝導ナノワイヤ単一光子検出器を用いた時間分解光子検出システム用高時間分解能SFQ時間-ディジタル変換器の設計 (超伝導エレクトロニクス)
明連 広昭; 神谷 遼太郎; 會田 晃太; 成瀬 雅人; 田井野 徹; 康 琳; 陳 健; 呉 培亨
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：119, 号：219, 開始ページ：23, 終了ページ：26, 2019年10月09日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40022064450, CiNii Books ID：AN10012885
高Jcプロセスを用いたSFQ論理によるディジタルSQUID磁束計の性能評価 (超伝導エレクトロニクス)
板垣 航希; 松縄 諒; 大嶋 一太; 長谷川 雄一; 成瀬 雅人; 田井野 徹; 明連 広昭; Okabe Kosuke
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：119, 号：164, 開始ページ：49, 終了ページ：53, 2019年08月09日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021996943, CiNii Books ID：AN10012885
SFQ論理によるディジタルSQUID磁束計の実装に関する検討
明連 広昭; 松繩 諒; 板垣 航希; 大嶋 一太; 長谷川 雄一; 成瀬 雅人; 田井野 徹
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：119, 号：10, 開始ページ：33, 終了ページ：38, 2019年04月19日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021885399, CiNii Books ID：AN10012885
集中定数型力学インダクタンス検出器のクロストーク特性評価 (超伝導エレクトロニクス)
桒田 正博; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：118, 号：415, 開始ページ：1, 終了ページ：5, 2019年01月23日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021801129, CiNii Books ID：AN10012885
サブ磁束量子フィードバックデジタルSQUID磁束計 : 高速化・小規模回路化に関する検討 (超伝導エレクトロニクス)
板垣 航希; 大嶋 一太; 長谷川 雄一; 松縄 諒; 岡部 公亮; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：118, 号：415, 開始ページ：7, 終了ページ：11, 2019年01月23日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021801158, CiNii Books ID：AN10012885
超伝導ナノワイヤを用いた光子数検出器の比較 (超伝導エレクトロニクス)
明連 広昭; 神谷 遼太郎; 傳田 哲史; 寺井 誠; 成瀬 雅人; 田井野 徹; 康 琳; 陳 健; 呉 培亨
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：118, 号：233, 開始ページ：7, 終了ページ：12, 2018年10月10日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021713682, CiNii Books ID：AN10012885
1次sincフィルタによるサブ磁束量子フィードバックデジタルSQUID磁束計の設計 (超伝導エレクトロニクス)
松縄 諒; 岡部 公亮; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：118, 号：178, 開始ページ：13, 終了ページ：17, 2018年08月09日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021657530, CiNii Books ID：AN10012885
高温超伝導体マイクロ波共振器を用いた放射線検出器の開発 (超伝導エレクトロニクス)
成瀬 雅人; 久保田 立記; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：118, 号：11, 開始ページ：23, 終了ページ：27, 2018年04月20日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021538293, CiNii Books ID：AN10012885
超伝導ナノワイヤ単一光子検出器アレイによる高速光子数検出器の応用 (超伝導エレクトロニクス)
明連 広昭; 大田 一喜; 傳田 哲史; 成瀬 雅人; 田井野 徹; 康 琳; 陳 健; 呉 培亨
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：117, 号：223, 開始ページ：23, 終了ページ：28, 2017年10月04日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021374188, CiNii Books ID：AN10012885
サブ磁束量子フィードバックを用いたデジタルSQUIDの高速化 (超伝導エレクトロニクス)
岡部 公亮; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：117, 号：171, 開始ページ：49, 終了ページ：53, 2017年08月09日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021317932, CiNii Books ID：AN10012885
デジタル信号処理回路用単一磁束量子論理高速up/downカウンタ回路の設計 (超伝導エレクトロニクス)
神谷 遼太郎; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：117, 号：171, 開始ページ：55, 終了ページ：59, 2017年08月09日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021317973, CiNii Books ID：AN10012885
サブ磁束量子フィードバックによるデジタルSQUID磁束計の設計とその応用 (超伝導エレクトロニクス)
明連 広昭; 岡部 公亮; 神谷 遼太郎; 成瀬 雅人; 田井野 徹
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：117, 号：10, 開始ページ：1, 終了ページ：5, 2017年04月21日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40021187002, CiNii Books ID：AN10012885
単一磁束量子増幅器を用いた超伝導ナノワイヤ単一光子検出器アレイによる光子数検出器 (超伝導エレクトロニクス)
大田 一喜; 成瀬 雅人; 田井野 徹; 康 琳; 陳 健; 呉 培亨; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：116, 号：269, 開始ページ：43, 終了ページ：46, 2016年10月26日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40020991413, CiNii Books ID：AN10012885
磁場印加用コイル埋め込み型STJの作製と評価 (超伝導エレクトロニクス)
酒井 功樹; 山口 兼司; 仲川 博; 青柳 昌宏; 成瀬 雅人; 明連 広昭; 田井野 徹
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：116, 号：175, 開始ページ：5, 終了ページ：8, 2016年08月08日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40020932093, CiNii Books ID：AN10012885
埋め込み型STJの作製と特性に関する評価 (超伝導エレクトロニクス)
森田 浩平; 松本 功; 青柳 昌宏; 成瀬 雅人; 明連 広昭; 田井野 徹
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：116, 号：175, 開始ページ：9, 終了ページ：12, 2016年08月08日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40020932115, CiNii Books ID：AN10012885
高温超伝導体を用いた放射線検出器アレイの開発 (超伝導エレクトロニクス)
久保田 立記; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：116, 号：175, 開始ページ：13, 終了ページ：17, 2016年08月08日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40020932118, CiNii Books ID：AN10012885
NbN並列-直列型超伝導ナノワイヤによる単一光子検出器の高速応答 (超伝導エレクトロニクス)
前田 優; 塩島 俊也; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：116, 号：175, 開始ページ：41, 終了ページ：44, 2016年08月08日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40020932272, CiNii Books ID：AN10012885
ミリ波広帯域マイクロストリップ交差構造の開発 (超伝導エレクトロニクス)
増田 聖; 成瀬 雅人; 田井野 徹; 明連 広昭; 関本 裕太郎; 新田 冬夢
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：116, 号：175, 開始ページ：25, 終了ページ：28, 2016年08月08日
電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：40020932195, CiNii Books ID：AN10012885
C-8-2 弛張振動共振回路を結合したDROS比較器を用いたデジタルSQUID(C-8.超伝導エレクトロニクス,一般セッション)
小林 亮太; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会総合大会講演論文集, 巻：2016, 号：2, 開始ページ：30, 終了ページ：30, 2016年03月01日
一般社団法人電子情報通信学会, 日本語
CiNii Articles ID：110010026112, CiNii Books ID：AN10471452
超伝導マイクロ共振器による放射線検出器の開発 (超伝導エレクトロニクス)
成瀬 雅人; 宮本 法明; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：114, 号：247, 開始ページ：39, 終了ページ：42, 2014年10月15日
超伝導共振器の特性を利用した力学インダクタンス検出器(MKID:Microwave Kinetic Inductance Detectors)を用いて、ガンマ線イメージングカメラの開発を行っている。MKIDの中でも検出器感度が高い即ち電流密度が高い部分が平面的に広がっている分布定数型(LeKID:Lumped-element KID)を採用した。我々はまず、放射線カメラの原理実証として超伝導材に実績のあるニオブを使用し、0.3K以下で10素子の検出器の特性評価を行った。0.3Kにおいて、10素子中8素子が動作しの共振Q値は50000-110000程度と理論値と比べて一桁から半桁程低い値であった。また、Cs-137を放射線源から放射される662keVのガンマ線を照射し、検出性能評価を試みた。シリコン基板を挟んだ検出器の裏面に厚さ2mmの鉛吸収体を取り付けた素子と取り付けていない素子の特性を比較した結果、吸収体直下の素子の方が4倍程度高いイベントレートであったが、高いバックグラウンドにより放射線源からのイベントを直接観測することはできなかった。今後はバックグラウンドイベント及び素子雑音の低減によって662keV光子のイベント検出を目指す。
一般社団法人電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：110009959085, CiNii Books ID：AN10012885
C-8-1 サブ磁束量子分解能をもつデジタルSQUID磁束計の設計(C-8.超伝導エレクトロニクス,一般セッション)
高徳 耕平; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会ソサイエティ大会講演論文集, 巻：2014, 号：2, 開始ページ：15, 終了ページ：15, 2014年09月09日
一般社団法人電子情報通信学会, 日本語
CiNii Articles ID：110009882127, CiNii Books ID：AN10489017
C-8-14 デジタルSQUID用低消費電力8ビットアップダウンカウンタの設計(C-8.超伝導エレクトロニクス,一般セッション)
張 冰; 成瀬 雅人; 田井野 徹; 明連 宏昭
電子情報通信学会ソサイエティ大会講演論文集, 巻：2014, 号：2, 開始ページ：28, 終了ページ：28, 2014年09月09日
一般社団法人電子情報通信学会, 日本語
CiNii Articles ID：110009882210, CiNii Books ID：AN10489017
超伝導ナノワイヤ検出器を用いた光子数検出器用単一磁束量子論理デジタル信号処理回路 (超伝導エレクトロニクス)
武田 俊亮; 成瀬 雅人; 田井野 徹; 明連 広昭; 陳 健; 呉 培亨
電子情報通信学会技術研究報告 = IEICE technical report : 信学技報, 巻：113, 号：232, 開始ページ：83, 終了ページ：87, 2013年10月02日
伝導ナノワイヤ単一光子検出器(Superconducting Nanowire Single Photon Detector: SNSPD)は、低い暗計数率、高速応答、低ジッタ、高い量子効率などの特徴があり、単一光子を用いた量子暗号通信用の単一光子検出器や飛行時間(TOF)型質量分析装置の高速な検出器として注目されている。SNSPDの読み出し回路にはSNSPDと同じく極低温で動作し、高速かつ低ジッタで動作する単一磁束量子(Single Flux Quantum: SFQ)論理回路による読み出し回路が検討されている。並列SNSPDは、同時に検出された光子数に比例した大きさの電流パルスを発生するため、光子数検出器として動作する。この並列SNSPDは量子暗号通信用の単一光子源の評価やエネルギー分解能を付加したTOF型質量分析器用の検出器として期待されている。本研究では、この光子数検出可能な並列SNSPDの応答信号をSFQ論理回路により読み出す回路を設計・試作し、動作確認を行った。
一般社団法人電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：110009815147, CiNii Books ID：AN10012885
C-8-7 デジタルSQUID用磁気シールド構造を持つSFQ論理セルの設計(C-8.超伝導エレクトロニクス,一般セッション)
中川 裕仁; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会ソサイエティ大会講演論文集, 巻：2013, 号：2, 開始ページ：25, 終了ページ：25, 2013年09月03日
一般社団法人電子情報通信学会, 日本語
CiNii Articles ID：110009735804, CiNii Books ID：AN10489017
C-8-8 光子数検出用SFQ光子数識別回路の設計(C-8.超伝導エレクトロニクス,一般セッション)
武田 俊亮; 成瀬 雅人; 田井野 徹; 明連 広昭; 陳 健; 呉 培亨
電子情報通信学会ソサイエティ大会講演論文集, 巻：2013, 号：2, 開始ページ：26, 終了ページ：26, 2013年09月03日
一般社団法人電子情報通信学会, 日本語
CiNii Articles ID：110009735805, CiNii Books ID：AN10489017
マイクロ波超伝導共振器を用いた高感度テラヘルツ波検出器の開発 (超伝導エレクトロニクス)
成瀬 雅人; 渡辺 芳晴; 布川 裕真; 田井野 徹; 明連 広昭
電子情報通信学会技術研究報告 : 信学技報, 巻：113, 号：11, 開始ページ：21, 終了ページ：25, 2013年04月19日
機械式冷凍で持続可能な4Kで動作する高感度テラヘルツ波検出器の基礎開発を行ってきた。検出器には超伝導検出器の1種である力学インダクタンス検出器を採用した。検出器の動作温度を4Kとするために、検出器を構成する超伝導材料としてバルクの超伝導転移温度が約16Kと高く、また高感度化に必要な高品質膜が作製しやすい窒化ニオブ(NbN)を採用した。窒化ニオブ膜はMgO基板上にマグネトロンスパッタ法で成長させ、175nmで超伝導転移温度15.7Kと良好な結果を得た。また、単位体積当たりの検出器数を増やす際に問題となる素子間クロストーク量を電磁界解析ソフトDesignerで推定した。3つの異なる構造についてクロストーク量を比較し、クロストークの原因は誘導性結合と容量性結合によって説明できることを示す。また、クロストークを抑制するためには検出器のインダクタンス部分を渦巻き型にすることが有効であることを示す。
一般社団法人電子情報通信学会, 日本語
ISSN：0913-5685, CiNii Articles ID：110009768239, CiNii Books ID：AN10012885
C-8-13 STJアレイ検出器用時間分割多重化回路の設計(C-8.超伝導エレクトロニクス)
赤松 祐太; 佐々木 木亮; 成瀬 雅人; 田井野 徹; 明連 広昭
電子情報通信学会総合大会講演論文集, 巻：2013, 号：2, 開始ページ：44, 終了ページ：44, 2013年03月05日
一般社団法人電子情報通信学会, 日本語
CiNii Articles ID：110009767082, CiNii Books ID：AN10471452
反射防止膜を用いたTHz波用STJ検出器の特性評価鈴木宏宣; 田井野徹; 有吉誠一郎; 大谷知行; 明連広昭
応用物理学会学術講演会講演予稿集(CD-ROM),
巻：72nd,
開始ページ：ROMBUNNO.31A-W-9, 2011年08月16日
日本語
J-Global ID：201102227274473899 基板吸収型STJを用いた大面積THz波検出器山下直人; 青木一隆; 渡邉穣; 石井宏和; 田井野徹; 大谷知行; 澁谷孝幸; 有吉誠一郎; 佐藤広海; 明連広昭
応用物理学会学術講演会講演予稿集,
巻：70th,
号：1,
開始ページ：286, 2009年09月08日
日本語
J-Global ID：200902243020402735 基板吸収型並列アレイSTJ検出器によるTHz波の検出青木一隆; 山下直人; 渡邉穣; 石井宏和; 田井野徹; 大谷知行; 渋谷孝幸; 有吉誠一郎; 佐藤広海; 明連広昭
応用物理学会学術講演会講演予稿集,
巻：69th,
号：1,
開始ページ：249, 2008年09月02日
日本語
J-Global ID：200902215279866337 超伝導トンネル接合検出器を用いたTHz波分光測定山下直人; 青木一隆; 渡邉穣; 石井宏和; 田井野徹; 大谷知行; 渋谷孝幸; 有吉誠一郎; 佐藤広海; 明連広昭
応用物理学会学術講演会講演予稿集,
巻：69th,
号：1,
開始ページ：249, 2008年09月02日
日本語
J-Global ID：200902293363389413 C-8-9 超伝導トンネル接合素子アレイ用MUXの高速動作(C-8. 超伝導エレクトロニクス,一般セッション)
吉澤 有; 田井野 徹; 明連 広昭; 高田 進
電子情報通信学会総合大会講演論文集, 巻：2008, 号：2, 開始ページ：56, 終了ページ：56, 2008年03月05日
一般社団法人電子情報通信学会, 日本語
CiNii Articles ID：110006865619, CiNii Books ID：AN10471452
基板吸収型並列STJアレイ検出器によるTHz検出器の高感度化石井宏和; 田井野徹; 大谷知行; 渋谷孝幸; 有吉誠一郎; 佐藤広海; 明連広昭; 高田進
応用物理学会学術講演会講演予稿集,
巻：68th,
号：1,
開始ページ：305, 2007年09月04日
日本語
J-Global ID：200902238823361325 C-8-4 超伝導トンネル接合素子アレイ用MUXの設計(C-8.超伝導エレクトロニクス,一般講演)
吉澤 有; 田井野 徹; 明連 広昭; 高田 進
電子情報通信学会ソサイエティ大会講演論文集, 巻：2007, 号：2, 開始ページ：31, 終了ページ：31, 2007年08月29日
一般社団法人電子情報通信学会, 日本語
CiNii Articles ID：110006628994, CiNii Books ID：AN10489017
X-ray detection using superconducting tunnel junction shaped normal-distribution-function Tohru Taino; Tomohiro Nishihara; Koichi Hoshino; Hiroaki Myoren; Hiromi Sato; Hirohiko M. Shimizu; Susumu Takada
巻：E90C,
号：3,
開始ページ：566,
終了ページ：569, 2007年03月
A normal-distribution-function-shaped superconducting tunnel junction (NDF-STJ) which consists of Nb/Al-AlOx/Al/Nb has been fabricated as an X-ray detector. Current - voltage characteristics were measured at 0.4 K using three kinds of STJs, which have the dispersion parameters sigma of 0.25, 0.45 and 0.75. These STJs showed very low subgap leakage current of about 5 nA. By irradiating with 5.9 keV X-rays, we obtained the spectrum of these NDF-STJs. They showed good energy resolution with small magnetic fields of below 3 mT, which is about one-tenth of those for conventional-shaped STJs.
英語
DOI：https://doi.org/10.1093/ietele/e90-c.3.566DOI ID：10.1093/ietele/e90-c.3.566,
ISSN：0916-8524,
eISSN：1745-1353,
CiNii Articles ID：30026214645,
Web of Science ID：WOS:000245194400004 Al系超伝導トンネル接合素子の作製と評価
鎌田幸佑; 田井野徹; 佐藤広海; 明連広昭; 高田進
電子情報通信学会研究会資料, 巻：SCE2007-28, 開始ページ：19, 終了ページ：22, 2007年
THz波検出用基板吸収型超伝導トンネル接合素子
田井野徹; 石井宏和; 吉村正太; 明連広昭; 高田進; 大谷知行; 有吉誠一郎; 佐藤広海; 清水裕彦; 川瀬晃道
電子情報通信学会技術研究報告, 巻：106, 号：403(ED2006 184-199), 開始ページ：53, 終了ページ：57, 2006年12月01日
近年テラヘルツ波は工学、医学、理学など様々な分野で注目を集めている。我々はテラヘルツ波の新たな検出器として、超伝導トンネル接合素子(STJ)に着目し、その検出器開発を行っている。我々の提案する検出器は、STJ直下に存在する基板に対してテラヘルツ波を照射して、基板内で発生するフォノンを利用する"基板吸収型STJ"である。本論文では、基板吸収型STJを用いたテラヘルツ波検出のこれまでの実験について報告する。
一般社団法人電子情報通信学会, 日本語
ISSN：0913-5685, J-Global ID：200902265169918398, CiNii Articles ID：110006162469
THz波検出のための基板吸収型STJ検出器の高感度化石井宏和; 吉村正太; 田井野徹; 明連広昭; 大谷知行; 渋谷孝幸; 有吉誠一郎; 佐藤広海; 延與秀人; 川瀬晃道; 高田進
応用物理学会学術講演会講演予稿集,
巻：67th,
号：1,
開始ページ：260, 2006年08月29日
日本語
J-Global ID：200902205818711509 基板吸収型STJ素子のTHz波検出特性吉村正太; 中野蘭; 田井野徹; 明連広昭; 大谷知行; 渋谷孝幸; 有吉誠一郎; 佐藤広海; 清水裕彦; 川瀬晃道; 高田進
応用物理学会学術講演会講演予稿集,
巻：66th,
号：1,
開始ページ：203, 2005年09月07日
日本語
J-Global ID：200902289999395564 X-ray detection using superconducting tunnel junctions with polyimide insulation layer M Yoshida; K Hoshino; T Taino; H Myoren; S Takada; K Kikuchi; H Nakagawa; M Aoyagi; H Sato; HM Shimizu
巻：15,
号：2,
開始ページ：606,
終了ページ：608, 2005年06月
We have fabricated Nb-based superconducting tunnel junctions (STJs) with Al trapping layers using the photosensitive polyimide insulation layer for X-ray detector. It is possible to simplify the fabrication process of the STJs, because the photosensitive polyimide is used as the insulation layer instead of conventional inorganic insulation films without an etching process in a vacuum chamber. The polyimide insulation layer expects to be stable for thermal cycling between 0.3 K and room temperature. The preliminary experiments of 5.9 keV radiation shows the energy resolution of 86 eV.
英語
DOI：https://doi.org/10.1109/TASC.2005.849955DOI ID：10.1109/TASC.2005.849955,
ISSN：1051-8223,
Web of Science ID：WOS:000229765300133 Double relaxation oscillation SQUID with a 4JL on-chip digital flux locked-loop circuit H Myoren; M Goto; T Taino; K Kikuchi; H Nakagawa; K Tokoro; M Aoyagi; S Takada
巻：15,
号：2,
開始ページ：332,
終了ページ：335, 2005年06月
Double relaxation oscillation SQUID (DROS) combined with an on-chip superconducting digital flux locked-loop (FLL) circuit has been proposed. In this study, we described superconducting digital FLL circuit which consists of an 8-bit up/down counter and an 8-bit R-2R ladder D/A converter. The circuit was designed using 4-Junction Logic (4JL)-gates which are driven by a two phase power supply. In the up/down counter, we employed binary carry lookahead (BCL) circuits for high-speed operation. Logic simulations for the BCL 8-bit up/down counter showed correct operation up to 4 GHz, assuming a 2.5 kA/cm(2) Nb/Al-AIO(x)/Nb junction technology. From simulation results high slew rate of 10(7)Phi(0)/s and dynamic range of 2.5 Phi(0) can be expected.
英語
DOI：https://doi.org/10.1109/TASC.2005.849825DOI ID：10.1109/TASC.2005.849825,
ISSN：1051-8223,
Web of Science ID：WOS:000229765300065 Detection of direct and indirect terahertz waves using a Nb-based superconducting tunnel junctionC Otani; R Nakano; T Taino; T Shibuya; S Ariyoshi; H Myoren; H Sato; HM Shimizu; S Takada; K Kawase
巻：1,
開始ページ：263,
終了ページ：264, 2005年
We are developing a broadband THz detectors using Nb-based superconducting tunnel junctions. We found two components in a current signal for 1-2 THz pulse input. From the comparison of results obtained for the signals, the frequency response for the different size of STJs and the STJs fabricated on different substrate materials, we demonstrate that they correspond to photons absorbed with the superconductor electrode (refered as 'direct' component) and phonons generated by photons absorbed with the substrate (refered as 'phonon-mediated' component).
英語
SCOPUS ID：33846529873,
Web of Science ID：WOS:000237170000134 基板吸収型超伝導トンネル接合素子によるTHz波検出<論文>
中野 蘭; 田井野 徹; 明連 広昭; 高田 進
埼玉大学紀要, 工学部, 第1部論文集, 巻：1, 号：38, 開始ページ：18, 終了ページ：21, 2005年
Terahertz detector using a Nb-based superconducting tunnel junction
C. Otani; K. Hoshino; T. Taino; H. Myoren; R. Nakano; S. Ariyoshi; H. Sato; H. M. Shimizu; S. Takada; K. Kawase
Conference Digest of the 2004 Joint 29th International Conference on Infrared and Millimeter Waves and 12th International Conference on Terahertz Electronics, 開始ページ：243, 終了ページ：244, 2004年12月01日
We have developed a terahertz (THz) radiation detector using a Nb-based superconducting tunnel junction (STJ). The STJ was fabricated on a stoichiometric LiNbO 3 substrate. The incident THz photons absorbed by the substrate generate THz phonons, and a substantial amount of the phonons are detected by the STJ. The detector is expected to be sensitive to a wideband THz/far-infrared radiation above the energy gap of the Mb superconductor. We radiated monochromatic nanosecond THz pulses with the repetition rate of 49 Hz, and detected the corresponding periodic signals for the 1.1-1.9 THz radiation. ©2004 IEEE.
SCOPUS ID：20144386844
β-Taトラッピング層をもつNb系超伝導トンネル素子を用いたフォトン検出器
明連 広昭; 田井野 徹; 高田 進
埼玉大学紀要 工学部, 巻：37, 号：37, 開始ページ：3, 終了ページ：8, 2004年
埼玉大学工学部, 日本語
ISSN：0916-6394, CiNii Articles ID：40006332164, CiNii Books ID：AN00095740
On-chip coil-integrated STJ using the persistent superconducting current for photon detectors K Kikuchi; T Taino; M Nanme; H Nakagawa; M Aoyagi; H Sato; H Akoh; T Iizuka; H Myoren; S Takada; K Maehata; K Ishibashi; H Sato; T Ikeda; C Otani; Y Takizawa; T Oku; K Kawai; H Miyasaka; HM Shimizu; H Kato; H Watanabe
巻：13,
号：2,
開始ページ：1132,
終了ページ：1135, 2003年06月
A superconducting tunnel junction (STJ) is very attractive for use in high-energy-resolution photon detectors because. of its small energy gap. To detect a single photon, the Josephson current of the STJ has had to be suppressed by an external magnetic field. We demonstrated an on-chip coil-integrated STJ photon detector, which excludes the external magnetic field, allowing a small device size. A normal-distribution function shape was adopted for the superconducting electrodes, which makes the magnetic field supplied to the STJ small. We devise a new superconducting, photon detector by combining the above techniques. A new Josephson switching gate is also integrated on the same detector chip in order to drive an on-chip integrated coil by a persistent superconducting current. This behavior was confirmed experimentally using the technology of the fabrication process of the Nb/Al-AlOx/Nb Josephson tunnel junction.
英語
DOI：https://doi.org/10.1109/TASC.2003.814173DOI ID：10.1109/TASC.2003.814173,
ISSN：1051-8223,
Web of Science ID：WOS:000184241700263 Normal-distribution-function-shaped Josephson tunnel junctions K Kikuchi; H Myoren; T Iizuka; S Takada
巻：77,
号：22,
開始ページ：3660,
終了ページ：3661, 2000年11月
We have investigated the magnetic field dependence of the Josephson tunnel junctions whose shape is defined with a normal-distribution function. It was revealed that the normal-distribution-shaped Josephson tunnel junctions show an exponential decay and no side lobes of the Josephson current as the external magnetic field is increased. This behavior was confirmed experimentally by using the Nb/AlOx/Nb tunnel junctions with a Josephson critical current density of J(c)=50 A/cm(2), and an area of 10 000 mum(2) corresponding to the "small" junction region. Normal-distribution junctions should have a potential for wide applications to photon detection since the external magnetic field to suppress the Josephson current can be lowered to less than one tenth that of other junctions reported. (C) 2000 American Institute of Physics. [S0003-6951(00)04247-9].
英語
DOI：https://doi.org/10.1063/1.1328045DOI ID：10.1063/1.1328045,
ISSN：0003-6951,
CiNii Articles ID：80012137640,
Web of Science ID：WOS:000165396400059
