Synthesis and high-field magnetic measurement of Ba2Sn2+xMe1+xFe10-2xO22H. Harasawa; H. Mitamura; M. Tokunaga; K. Kakizaki; K. Kamishima
Journal of the Magnetics Society of Japan,
巻：48,
号：5,
開始ページ：88,
終了ページ：93, 2024年09月,
［査読有り］,
［最終著者, 責任著者］The Magnetics Society of Japan, 研究論文（学術雑誌）
DOI：https://doi.org/10.3379/msjmag.2409r002DOI ID：10.3379/msjmag.2409r002,
ISSN：1882-2924,
eISSN：1882-2932 Stable Formation and Enhanced Magnetism: Modified Compositions in 18H-type Hexaferrite CrystalsKenji Kamishima; Masato Takayama; Taro Yasui; Kazuya Watanabe; Koichi Kakizaki
Journal of the Physical Society of Japan,
巻：93,
号：8,
開始ページ：084802, 2024年07月,
［査読有り］,
［筆頭著者, 責任著者］Physical Society of Japan, 研究論文（学術雑誌）
DOI：https://doi.org/10.7566/jpsj.93.084802DOI ID：10.7566/jpsj.93.084802,
ISSN：0031-9015,
eISSN：1347-4073 Synthesis of Fe2+-based 18H-type ferrite, Ba5Fe2+2-xFe3+12+2xTi3-xO31 Sora Nakahara; Koichi Kakizaki; Kenji Kamishima
Journal of Magnetism and Magnetic Materials,
巻：602,
開始ページ：172175,
終了ページ：172175, 2024年05月,
［査読有り］,
［最終著者, 責任著者］Elsevier BV, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.jmmm.2024.172175DOI ID：10.1016/j.jmmm.2024.172175,
ISSN：0304-8853 新規18H型フェライト化合物結晶の発見神島 謙二
まてりあ,
巻：62,
号：9,
開始ページ：594,
終了ページ：599, 2023年09月,
［査読有り］,
［招待有り］,
［筆頭著者, 責任著者］Japan Institute of Metals, 研究論文（学術雑誌）
DOI：https://doi.org/10.2320/materia.62.594DOI ID：10.2320/materia.62.594,
ISSN：1340-2625,
eISSN：1884-5843 Synthesis of (Ca, Sr)-based W-type hexagonal ferrite Kenji Kamishima; Takehiro Sekigawa; Koichi Kakizaki; Kowashi Watanabe
Journal of Magnetism and Magnetic Materials,
巻：574, 2023年05月,
［査読有り］,
［筆頭著者, 責任著者］This investigation has examined the synthesis conditions and magnetic properties of (Ca, Sr)-based W-type hexagonal ferrite. Substituting Ca for Sr in CaxSr1−xZn2Fe16O27 (where 0≤x≤1) resulted in the formation of the W-type structure at x≤0.7 sintered at TS = 1250 and 1300°C. However, these W-type samples were accompanied by secondary spinel and hematite phases, making it necessary to modify the initial composition to form a single W-type phase. Eliminating the potential compositions of these secondary phases resulted in the optimal single-phase-forming condition of Ca: Sr: Zn: Fe = 0.55: 0.45: 0.88: 11.6 and TS = 1200°C. The magnetization of this sample at 5 K was 130.7 A m2/kg at 7 T, consistent with a model of a collinear magnetic structure. The Curie temperature of this sample was found to be 350°C.
研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.jmmm.2023.170670Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85151786216&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85151786216&origin=inwardDOI ID：10.1016/j.jmmm.2023.170670,
ISSN：0304-8853,
SCOPUS ID：85151786216 Synthesis conditions of off-stoichiometric BaFe9LiO15 polycrystalline and single-crystal samples K. Kamishima; H. Takahashi; K. Kakizaki; I. Yanase; T. Fujihara
Journal of Crystal Growth,
巻：593, 2022年09月,
［査読有り］,
［筆頭著者, 責任著者］We have determined the phase diagrams of BaO-Li2O-Fe2O3 about BaFe9LiO15, which we initially came across with unfamiliar Bragg peaks through our attempts to synthesize a kind of Y-type hexaferrite, Ba2Me2Fe12O22 with Me2 = LiFe. The initial composition of Ba: Fe: Li = 2.5: 23: 2 allowed us to obtain the single phase of BaFe9LiO15 despite its off-stoichiometry. The conditions for the formation of the single phase of BaFe9LiO15 were confirmed by synthesizing about 40 initial composition samples around Ba: Fe: Li = 2.5: 23: 2 at 1000, 1050, and 1100°C, respectively. Single crystals of BaFe9LiO15 were separated from the internal part of a disk-shaped sample with the initial composition of Ba: Fe: Li = 2.5: 23: 2 sintered at 1200°C. X-ray crystallography for a single crystal showed that the oxide has an orthorhombic structure (space group: Cmca) with a = 11.527(8) Å,b = 10.253(7) Å, and c = 9.450(6) Å, which is consistent with the previously-reported Rietveld analysis result of synchrotron-radiation X-ray diffraction experiments on BaFe9LiO15 powder. The temperature dependence of magnetization at μ0H = 0.1 T showed a slight change in slope around 200°C, consistent with the previously-reported antiferromagnetic transition temperature determined by Mössbauer spectroscopy.
研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.jcrysgro.2022.126755Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85132707032&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85132707032&origin=inwardDOI ID：10.1016/j.jcrysgro.2022.126755,
ISSN：0022-0248,
SCOPUS ID：85132707032 High Saturation Magnetization Calcium-Zinc Spinel Ferrite Prepared by Rapid Cooling J. Hashimoto; K. Kakizaki; K. Kamishima
Journal of the Magnetics Society of Japan,
巻：46,
号：3,
開始ページ：58,
終了ページ：63, 2022年,
［査読有り］,
［最終著者, 責任著者］To obtain a high magnetization Ca-Zn-based spinel ferrite, we investigated the synthesis conditions and magnetic properties of samples with compositions of Ca: Zn: Fe = 0.5: 2.5: 16-x (x = 1, 2, 3, 4, 5, 6, and 7) sintered at 1300°C and then cooled under different conditions (-200°C/hour or quenched in water). Quenching the sample at x = 3 resulted in the best sample with the highest magnetization of 146 emu/g at T = 1.8 K. We estimated the Fe2+ amount and molar ratio of the sample by using thermogravimetry/ differential thermal analysis (TG/DTA). The large lattice constant implied that the spinel contained Ca2+ ions at its transition metal sites, which possibly led to a cationic distribution contributing to the high magnetization.
研究論文（学術雑誌）
DOI：https://doi.org/10.3379/msjmag.2205R002Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85130270806&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85130270806&origin=inwardDOI ID：10.3379/msjmag.2205R002,
ISSN：0285-0192,
eISSN：1882-2932,
SCOPUS ID：85130270806 Restoration of the collinear spin arrangement in non-magnetic-ion-substituted M-type hexaferrite by high magnetic fields K. Kamishima; A. Yonezawa; K. Kakizaki; A. Miyake; H. Mitamura; M. Tokunaga
Journal of Magnetism and Magnetic Materials,
巻：538,
開始ページ：168251,
終了ページ：168251, 2021年11月,
［査読有り］,
［筆頭著者, 責任著者］Elsevier {BV}, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.jmmm.2021.168251DOI ID：10.1016/j.jmmm.2021.168251,
ISSN：0304-8853,
ORCID：98758008 Discovery of the new crystallographic phase of an exotic magnetic oxide: 18H-type hexaferrite Kazuya Watanabe; Takashi Fujihara; Kowashi Watanabe; Koichi Kakizaki; Kenji Kamishima
Journal of the Physical Society of Japan,
巻：89,
号：1, 2020年,
［査読有り］,
［最終著者, 責任著者］We have found an exotic magnetic oxide with unreported Bragg peaks through our attempts to substitute Zn2+ and Ti4+ for 2Fe3+ in Zn2Y-type hexaferrite (Ba2Zn2Fe12O22). Single crystals of the magnetic oxide were grown by a self-flux method with the approximate initial composition (Ba: Zn: Ti: Fe ¼ 2: 1: 1: 6) estimated by subtracting a zinc S-block composition (Zn2Fe4O8) from the Zn-Ti substituted Y-type composition of Ba2Zn3TiFe10O22. X-ray crystallography for a single crystal revealed that the magnetic oxide has a hexagonal structure (space group: P63= mmc) with a = 5.8383(3) Å and c = 43.1422(19) Å. This crystal structure can be interpreted as intercalation of three hexagonal BaTiO3 blocks into one T-block (Ba2Fe8O14) in the Y-type hexaferrite structure (T-S block stacking), which was conjectured under the name of “18H-type” hexaferrite. The actual composition of the crystal was estimated to be Ba5Fe12+2xTi3−xZn2−xO31 with x' 0:5. Polycrystalline samples of Ba5Fe12+2xTi3−xZn2−xO31 were successfully prepared at 0 ≤ x ≤ 1.0 and showed the Curie temperatures between 301 and 437 K. The assumption of a collinear ferrimagnetic structure in the 18H-type unit cell successfully explained the magnetization of Ba5Fe12+2xTi3−xZn2−xO31 at T = 5 K.
研究論文（学術雑誌）
DOI：https://doi.org/10.7566/JPSJ.89.014704Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85078593332&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85078593332&origin=inwardDOI ID：10.7566/JPSJ.89.014704,
ISSN：0031-9015,
eISSN：1347-4073,
SCOPUS ID：85078593332 Synthesis and magnetic properties of M2+Ti4+ substituted Ba12Fe28Ti15O84 N. Yasuda; S. Kittaka; Y. Kono; T. Sakakibara; K. Kakizaki; K. Kamishima
Journal of the Magnetics Society of Japan,
巻：44,
号：3,
開始ページ：70,
終了ページ：74, 2020年,
［査読有り］,
［最終著者, 責任著者］We investigated the synthesis conditions and magnetic properties of M-Ti substituted Ba12Fe28Ti15O84 with initial compositions of Ba12Fe28-2xTi15+xMxO84 (M = Zn, Mg, Ni, Cu, and Co) sintered at 1100-1300°C. The highest substitution amounts of M-Ti for Fe were consistent with the Ti-ion preference of each transition metal site reported before, suggesting that substituted Ti ions also preferred the sites with high Ti-ion occupancies. The spontaneous magnetizations and Curie temperatures were decreased as the substitution amount x was increased, which means that the substitution weakened the super-exchange interactions between Fe-O-Fe. The highest Zn-Ti substitution rate was lower than the other M-Ti substitution rates, which implies that Zn ions tend to enter specific M(2) and M(14) sites in Ba12Fe28Ti15O84. The sweep of the magnetic field from 0 to 80 kOe changed the relative dielectric constant of Ba12Fe28Ti15O84 by 0.283%. This variation of the dielectric constant caused by the application of magnetic fields is not negligible, showing that this compound should be categorized as a multiferroic material.
研究論文（学術雑誌）
DOI：https://doi.org/10.3379/msjmag.2005R004Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85084264273&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85084264273&origin=inwardDOI ID：10.3379/msjmag.2005R004,
ISSN：0285-0192,
eISSN：1882-2932,
SCOPUS ID：85084264273 Flux growth and magnetic properties of single crystals of hexagonal ferrite structures and a long-range-order structure T. Saho; T. Fujihara; K. Kakizaki; K. Kamishima
Journal of the Magnetics Society of Japan,
巻：44,
号：4,
開始ページ：91,
終了ページ：95, 2020年,
［査読有り］,
［最終著者, 責任著者］We prepared single crystals of six typical hexaferrites (M-type, W-type, X-type, Y-type, Z-type, and U-type) in order to investigate their formation, crystal size, and magnetic properties. In addition, we also investigated the conditions of single-crystal formation at several flux concentrations and cooling rates. We found that the growth of single crystals on the MY-line (Y-and Z-type) became more significant than that on the MS-line (W-type) under a slow-cooling condition. In contrast, the single crystals on the MS-line appeared with a relatively high cooling rate of 10°C/h., where the single crystals did not grow large. By using the self-flux method, we succeeded in synthesizing single crystals with a more complex structure with a possibility of being M2Y7 on the MY-line and investigating the magnetic properties.
研究論文（学術雑誌）
DOI：https://doi.org/10.3379/msjmag.2007R001Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85087379597&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=85087379597&origin=inwardDOI ID：10.3379/msjmag.2007R001,
ISSN：0285-0192,
eISSN：1882-2932,
SCOPUS ID：85087379597 Preparation of Sr-based hexagonal ferrite by controlling the oxidation state of Fe Meguro M.; Kakizaki K.; Kamishima K.
Transactions of the Materials Research Society of Japan,
巻：43,
号：3,
開始ページ：183,
終了ページ：186, 2018年06月,
［査読有り］,
［最終著者, 責任著者］We have investigated synthesis conditions and magnetic properties of Sr
2Fe
2+2Fe
3+12O
22 (Sr
2Fe
2Y). The main Y-type phase was observed for the sample synthesized with the initial composition of Sr:Fe
2+:Fe
3+=1.5:2:8 sintered at
TS=1200℃ and
PO2=10 Pa. The Curie temperature of Sr
2Fe
2Y was 643 K. The magnetization was 45.0 Am
2/kg at
T= 5 K and μ
0H=7 T. The difference in magnetization from the ideal collinear spin arrangement of Sr
2Fe
2Y is due to the existence of a minor Fe
3O
4-like spinel phase. The yield of Sr
2Fe
2Y phase was estimated to be 83 wt.%, suggesting successful synthesis of the Sr
2Fe
2Y hexaferrite.
The Materials Research Society of Japan, 英語
DOI：https://doi.org/10.14723/tmrsj.43.183DOI：https://doi.org/10.7566/jpsj.89.014704_references_DOI_WCaCRVotoVcsUCduXW0H2kbgfQQDOI ID：10.14723/tmrsj.43.183,
ISSN：1382-3469,
eISSN：2188-1650,
CiNii Articles ID：130007382955 Optimum Conditions for Synthesizing Fe Substituted Hibonite Nagumo H.; Kakizaki K.; Kamishima K.
Journal of the Magnetics Society of Japan,
巻：42,
号：1,
開始ページ：1,
終了ページ：4, 2018年,
［査読有り］,
［最終著者, 責任著者］We investigated the synthesis conditions and magnetic properties of Fe substituted hibonite with initial compositions of CaAl
xFe
y−xO
19−δ (1 ≤
x ≤ 3, 5 ≤
y ≤ 9) and CaAl
xFe
8-xO
19−δ (0.5 ≤
x ≤ 1.6) sintered at 1200–1300ºC. The optimum conditions for synthesizing the best magnetic hibonite were found to be the initial composition of Ca:Al:Fe = 1:0.6:7.4 and the sintering temperature of 1250ºC. The best magnetic hibonite was magnetized at 75.0 A·m
2/kg at
T = 5 K and
μ0H = 7 T. This magnetic moment can be interpreted with a model of the collinear magnetic structure. The Curie temperature of the best magnetic hibonite was 330ºC, which was the highest among those of iron-substituted hibonite samples.
The Magnetics Society of Japan, 英語
DOI：https://doi.org/10.3379/msjmag.1801r001DOI ID：10.3379/msjmag.1801r001,
ISSN：1882-2924,
eISSN：1882-2932,
CiNii Articles ID：130006301660,
CiNii Books ID：AA12749208 PdSb添加L10-FePt系薄膜の結晶配向性および磁気特性 柿崎 浩一; 高桑 啓; 神島 謙二
粉体および粉末冶金,
巻：64,
号：7,
開始ページ：355,
終了ページ：358, 2017年07月,
［査読有り］FePt thin films with L10 ordered structure are candidates for high-density magnetic recording media because of their high uniaxial magnetic anisotropy energy. The (Fe0.395Pt0.395Cu0.15 P0.02Pd0.04)100-xSbx thin films with various x were deposited directly on quartz glass substrates by a sputtering method. FePt ordered alloy thin films with (001) preferential orientation were achieved in Sb content of x ≥ 8.0 at.% with post-Annealing at 600°C for 1 hour under reduced pressure in a H2 atmosphere. However, the coercivity of these thin films decreased dramatically due to growing of the crystal grains. Therefore, in this study, we prepared the PdSb-FePt-(C4F8)n granular thin films to improve the coercivity. The Fe0.44Pt0.44Pd0.04Sb0.08-(C4F8)n granular thin film deposited at C4F8 partial pressure of 0.1 mTorr then annealed at 700°C for 1 hour under reduced pressure in a H2 atmosphere exhibited a large coercivity of 30 kOe.
Journal of the Japan Society of Powder and Powder Metallurgy, 日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.64.355DOI ID：10.2497/jjspm.64.355,
ISSN：0532-8799,
SCOPUS ID：85026385592 Synthesis and magnetic properties of Fe substituted hibonite Nagumo H.; Watanabe K.; Kakizaki K.; Kamishima K.
Journal of the Magnetics Society of Japan,
巻：41,
号：2,
開始ページ：20,
終了ページ：24, 2017年,
［査読有り］,
［最終著者, 責任著者］We have investigated the synthesis conditions and magnetic properties of Fe substituted hibonite with initial compositions of CaAl
12-xFe
xO
19 (0≤
x≤12) and CaAl
10-xFe
xO
19-δ (0≤
x≤10). The Fe doped hibonite can be synthesized at a sintering temperature of 1300˚C. The X-ray diffraction patterns of Fe substituted hibonite samples are in good agreement with the pattern of hibonite. The lattice parameter increased due to the difference between the radius of Al
3+ and that of Fe
3+. The magnetization and Curie temperature of the best sample (CaAl
2Fe
8O
19-δ) are 31 emu/g and 290˚C, respectively.
The Magnetics Society of Japan, 英語
DOI：https://doi.org/10.3379/msjmag.1701r001DOI ID：10.3379/msjmag.1701r001,
ISSN：1882-2924,
eISSN：1882-2932,
CiNii Articles ID：130005401748,
CiNii Books ID：AA12749208 Optimum preparation conditions of Fe-deficient Ca-based M-type ferrite Shigemura M.; Watanabe K.; Kakizaki K.; Kamishima K.
Journal of the Magnetics Society of Japan,
巻：41,
号：1,
開始ページ：10,
終了ページ：13, 2017年,
［査読有り］,
［最終著者, 責任著者］We investigated synthesis conditions and magnetic properties of Fe-deficient Ca-based hexagonal ferrites, Ca
1−xLa
xFe
yO
19−σ (
x = 0.1–0.3,
y = 2.0–10), and found the formation of M-type ferrite at
x = 0.1–0.3 and
y = 7.0–9.0 above 1200°C. Samples of
y = 2.0–6.0 showed deviation from the initial compositions since molten calcium-rich oxide (possibly CaFe
2O
4) leaked out from the samples above 1200°C. The X-ray diffraction pattern of Ca
0.8La
0.2Fe
8.0O
19−σ sintered at 1250°C demonstrates the single phase of M-type hexagonal ferrite. The saturation magnetization of this sample was 68.0 Am
2/kg at room temperature and its Curie temperature was about 400°C, which is slightly lower than that of the Sr-based M-type ferrite (460°C).
The Magnetics Society of Japan, 英語
DOI：https://doi.org/10.3379/msjmag.1611r002DOI ID：10.3379/msjmag.1611r002,
ISSN：1882-2924,
eISSN：1882-2932,
CiNii Articles ID：130005239721,
CiNii Books ID：AA12749208 Synthesis of non-magnetic-ion-substituted Ca-based M-type ferrite Shigemura M.; Kakizaki K.; Kamishima K.
Journal of the Magnetics Society of Japan,
巻：41,
号：5,
開始ページ：94,
終了ページ：98, 2017年,
［査読有り］,
［最終著者, 責任著者］We investigated the synthesis conditions and magnetic properties of non-magnetic-ion-substituted Ca-based hexagonal ferrites, Ca
0.8La
0.2Fe
8.0−2xMg
xTi
xO
19−σ (
x = 0.1–3.5) and Ca
0.8La
0.2Fe
y−xAl
xO
19−σ (
x = 1.0–5.0,
y = 8.0–10). We found that Mg-Ti-substituted Ca-based M-type ferrites formed at
x = 0.1 and 0.2 at above 1225ºC. The sample at
x = 0.1 showed the crystallographic single phase of M-type ferrite. The minimum Curie temperature of the Mg-Ti-substituted samples was 367ºC. Also, we found that the Al-substituted Ca-based M-type ferrites had the main phase of M-type ferrite in all samples. As the amount of substituted Al increased, the saturation magnetization and the Curie temperature decreased, and the coercivity increased. As the amount of substituted Al increased by Δ
x = 1, the Curie temperature decreased by Δ
TC = 50–70ºC. Al-substituted samples of
x = 1.0 and 2.0 sintered at 1300ºC had the single phase of M-type ferrite.
The Magnetics Society of Japan, 英語
DOI：https://doi.org/10.3379/msjmag.1708r001DOI ID：10.3379/msjmag.1708r001,
ISSN：1882-2924,
eISSN：1882-2932,
CiNii Articles ID：130006041674,
CiNii Books ID：AA12749208 Synthesis and Magnetic Properties of (Zn²⁺Ti⁴⁺) Substituted W-type and Y-type Ferrites Watanabe K; Kakizaki K; Kamishima K
Journal of the Magnetics Society of Japan,
巻：41,
号：6,
開始ページ：127,
終了ページ：131, 2017年,
［査読有り］,
［最終著者, 責任著者］We report the synthesis of (Zn
2+Ti
4+) substituted hexagonal ferrites, BaZn
2(Zn
0.5Ti
0.5)
xFe
16-xO
27 (W-type) and Ba
2Zn
2(Zn
0.5Ti
0.5)
xFe
12-xO
22 (Y-type), and the relationship between their composition and magnetic properties. Substituted W-type ferrite was synthesized in the region of 0.0 ≤
x ≤ 1.5. A decrease in the Curie temperature of the W-type phase indicated that the exchange interactions between the Fe
3+ ions weakened due to the substitution of Zn
2+ and Ti
4+ ions. Spontaneous magnetization (
σS) at
x = 0.5 was similar to that at
x = 0.0. This reflects the equal distribution of nonmagnetic Zn
2+ and Ti
4+ ions to spin down sites and spin up sites, respectively. At
x > 0.5,
σS decreased clearly, which was possibly caused by a deviation from the collinear arrangement. Substituted Y-type ferrite was also obtained up to
x = 0.5. The Y-type phase is more unstable than the W-type phase with respect to this substitution rate.
公益社団法人 日本磁気学会, 英語
DOI：https://doi.org/10.3379/msjmag.1710r001DOI ID：10.3379/msjmag.1710r001,
ISSN：1882-2924,
eISSN：1882-2932,
CiNii Articles ID：130006192326,
CiNii Books ID：AA12749208 Synthesis and magnetic characterization of Sr-based Ni2X-type hexaferrite K. Kamishima; T. Mashiko; K. Kakizaki; M. Sakai; K. Watanabe; H. Abe
AIP Advances,
巻：5,
号：10,
開始ページ：107132 1-10, 2015年10月,
［査読有り］,
［筆頭著者, 責任著者］We have investigated the synthesis conditions, and the magnetic properties of the Sr2Ni2X-type hexagonal ferrite, Sr2Ni2Fe28O46. The Sr2Ni2X-type hexaferrite was synthesized at 1240 degrees C. The spontaneous magnetization at 5 K was 44.2 mu(B)/f.u., suggesting that most of the Ni2+ ions are at the up-spin octahedral sites in the spinel-structure blocks within the model of a Neel-type collinear ferrimagnetic structure. The Curie temperature of the Sr2Ni2X-type hexaferrite was estimated to be T-C[Sr2Ni2X] = 472 degrees C. This is consistent with the difference of the block stacking structures of SrM-type, Sr2Ni2X-type, SrNi2W-type, and nickel spinel ferrites. (C) 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.
AMER INST PHYSICS, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1063/1.4934792DOI ID：10.1063/1.4934792,
ISSN：2158-3226,
Web of Science ID：WOS:000364228800032 Crystallographic and magnetic properties of Cu2U-type hexaferrite K. Kamishima; R. Tajima; K. Watanabe; K. Kakizaki; A. Fujimori; M. Sakai; K. Watanabe; H. Abe
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS,
巻：375,
開始ページ：54,
終了ページ：60, 2015年02月,
［査読有り］,
［筆頭著者, 責任著者］We have investigated the synthesis conditions, and the magnetic properties of the Cu2U-type hexagonal ferrite, Ba4Cu2Fe36O60. The Cu2U-rype hexaferrite was synthesized at the sintering temperature of 1050 degrees C with the initial composition of Ba4.4Cu2Fe37.6O62.8 (Cu2U + 0.2T-block). The saturation magnetizations at 300 K and 5 K are 46.8 A m(2)/kg and 65.0 A m(2)/kg, respectively. The Curie temperature is 420 degrees C which is lower than that of the M-type ferrite (450 degrees C) but higher than that of the Cu2Y-type ferrite (320 degrees C). The amount of the nonmagnetic impurity in this sample is estimated to be about 10 wt% by the electron probe micro analysis. We estimated the expected saturation magnetization to be 652 A m(2)/kg, by assuming the model of a Neel-type ferrimagnetic structure and the reduction of magnetization by the 10 wt% nonmagnetic impurity. This is consistent with the observed magnetization of 65.0 A m(2)/kg at 5 K. (C) 2014 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.jmmm.2014.09.055DOI ID：10.1016/j.jmmm.2014.09.055,
ISSN：0304-8853,
eISSN：1873-4766,
Web of Science ID：WOS:000344949800009 Synthesis and Magnetic Properties of Fe₂W and Fe₂Y hexaferrites Koide M.; Kakizaki K.; Kamishima K.
Journal of the Magnetics Society of Japan,
巻：39,
号：4,
開始ページ：147,
終了ページ：150, 2015年,
［査読有り］,
［最終著者, 責任著者］We have investigated the synthesis conditions, and the magnetic properties of BaFe
2+2Fe
3+16O
27 (Fe
2W) and Ba
2Fe
2+2Fe
3+12O
22 (Fe
2Y). It is found that Fe
2W can be synthesized at a sintering temperature of 1300°C and Fe
2Y can be synthesized at a sintering temperature of 1000°C. The X-ray diffraction patterns for Fe
2W and Fe
2Y samples are in good agreement with the pattern of BaCo
2+2Fe
3+16O
27 (Co
2W) and that of Ba
2Co
2+2Fe
3+12O
22 (Co
2Y). It is also found that the Curie temperatures of Fe
2W and Fe
2Y ferrites are 503 and 375°C, respectively.
公益社団法人 日本磁気学会, 日本語
DOI：https://doi.org/10.3379/msjmag.1506r003DOI：https://doi.org/10.7566/jpsj.89.014704_references_DOI_BYFenyYFdPfKYNSahsBwYyjr44EDOI ID：10.3379/msjmag.1506r003,
ISSN：1882-2924,
eISSN：1882-2932,
CiNii Articles ID：130005087628,
CiNii Books ID：AA12297999 Small ordered magnetic moment in a weak itinerant electron ferromagnet Sc3In K. Kamishima; R. Note; T. Imakubo; K. Watanabe; H. A. Katori; A. Fujimori; M. Sakai; K. V. Kamenev
JOURNAL OF ALLOYS AND COMPOUNDS,
巻：589,
開始ページ：37,
終了ページ：41, 2014年03月,
［査読有り］,
［筆頭著者, 責任著者］We performed neutron diffraction study of Sc-In alloy which indicates that the ordered magnetic moment in this material is intrinsically tiny. This tiny magnetic moment (0.04-0.05 mu(B)/Sc) is not caused by the uncompensated antiferromagnetic ordering of large magnetic moments. The temperature dependence of the resistivity is in proportion to T-3/2, which suggests that this material is naturally close to the quantum critical point where ferromagnetism vanishes. This is consistent with the fact that this material shows ferromagnetism in an extremely narrow range of compositions which is typical of materials exhibiting quantum critical phenomenon. In the vicinity of the Curie temperature the magnetization depends on magnetic fields as M-5 proportional to mu H-0. This behavior for itinerant ferromagnets can be explained by assuming that the total spin fluctuation amplitude is conserved. (C) 2013 Elsevier B. V. All rights reserved.
ELSEVIER SCIENCE SA, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.jallcom.2013.11.032DOI ID：10.1016/j.jallcom.2013.11.032,
ISSN：0925-8388,
eISSN：1873-4669,
Web of Science ID：WOS:000330181400006 Magnetic properties of La-Co substituted Ba ferrite thin films prepared by a sol-gel method H. Yoshiga; K. Kamishima; N. Hiratsuka; K. Kakizaki
Funtai Oyobi Fummatsu Yakin/Journal of the Japan Society of Powder and Powder Metallurgy,
巻：61,
開始ページ：S314,
終了ページ：S317, 2014年,
［査読有り］La-Co substituted BaM (La-CoBaM) thin films have been prepared by a sol-gel technique involving a spin coating of metal-organic compounds. We report the effects of Pt under-layer on the c-axis orientation of La-CoBaM films and their magnetic properties. On the Pt under-layer with the thickness of 120 nm whose '111' axis oriented perpendicular to substrate surface, the La-CoBaM films with the thickness ranging from 20 to 95 nm were coated at room temperature. These coated films were annealed at 900�C for 5h. in air. The Hc⊥/Hc// value for the La-CoBaM films with the thickness of 20 nm was 3.9 that was the largest of all samples. The c-axis of magnetoplumbite phase was oriented perpendicular to the film surface, that was caused by the effect of the (111) oriented Pt under-layer.
Journal of the Japan Society of Powder and Powder Metallurgy, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.61.S314DOI ID：10.2497/jjspm.61.S314,
ISSN：0532-8799,
SCOPUS ID：84988026269 超音波噴霧熱分解法により作製したNi-Znフェライトナノ粒子の微細構造および磁気特性 平塚 信之; 結城 翔三; 神島 謙二; 柿崎 浩一
粉体および粉末冶金,
巻：60,
号：6,
開始ページ：257,
終了ページ：262, 2013年06月,
［査読有り］Crystalline nano-sized Ni1-xZnxFe2O 4 (x = 0 ∼ 1.0) particles were prepared by ultrasonic spray pyrolysis from the spray sol-gel solution with Ni-, Zn- and Fe-nitrates and citric acid. The crystal lattice constant increased lineally with increasing Zn ion contents according to the Vegard's rule. All the prepared particles had the size of less than 100 nm, which were calculated with Scherrer equation and were observed by TEM. The average particle size of the samples containing Zn ions was about 50 nm. The sample with x = 0.3 had the maximum magnetization of 63 emu/g, which was 80 percent of the bulk material. It was supposed that the sample contained a super paramagnetic substance. The coercivity of the samples was much larger than that of the bulk ferrites. The coercivity of the samples decreased with the increase of Zn ion contents. Curie temperature also decreased with the increase of Zn ion contents. However, these values were higher than those of the bulk materials because of existence of Fe2+ ions and heterogeneous octahedral site distribution of Zn ions.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.60.257DOI ID：10.2497/jjspm.60.257,
ISSN：0532-8799,
SCOPUS ID：84880539807 Synthesis of a new U-type hexaferrite Ba4Cu2Fe36O60. R. Tajima; K. Kamishima; K. Kakizaki; N. Hiratsuka; A. Fujimori; M. Sakai; K. Watanabe
Trans. Mat. Res. Soc. Jpn,
巻：38,
号：3,
開始ページ：451,
終了ページ：454, 2013年,
［査読有り］英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.14723/tmrsj.38.451DOI ID：10.14723/tmrsj.38.451 超音波噴霧熱分解法によるナノMn-Znフェライト粒子の作製および磁気特性 富永 翔; 神島 謙二; 柿崎 浩一; 石丸 雄大; 平塚 信之
粉体および粉末冶金,
巻：59,
号：6,
開始ページ：337,
終了ページ：341, 2012年06月,
［査読有り］Nano-crystalline Mn-Zn ferrite powders (Mn1-xZn xFe2O4, x = 0∼1.0) have been prepared by ultrasonic spray pyrolysis method. Mn-Zn ferrite samples sintered at 700 °C had the single phase of spinel-type for all of the compositions. The lattice constant decreased with increasing Zn content and followed Vegard,s law. Curie temperature linearly decreased from that of MnFe2O4 (x = 0) with increasing Zn substitution rate. These results indicate that the Mn-Zn ferrite formed solid solution. The Mn-Zn ferrite particles were found to be in nano-size of 20∼30 nm by scanning electron microscopy. And their crystalline diameters were 15∼30 nm,determined by the use of Scherrer equation for X-ray diffraction peak broadening. Mn0.6Zn0.4Fe 2O4 sample had a magnetization value of 48 emu/g,which was lower than that of bulk sample (80emu/g). This is possibly caused by the existence of a disordered surface region on the nanoparticles, where the crystallographic and magnetic structures are disordered due to the nearly random distribution of cations and the canted spin arrangement.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.59.337DOI ID：10.2497/jjspm.59.337,
ISSN：0532-8799,
SCOPUS ID：84880444186 六方晶U型フェライトBa4Me2Fe36O60 (Me=Co, Ni, Mg)の作製プロセスの確立および磁気特性 佐々木 遼; 神島 謙二; 柿崎 浩一; 石丸 雄大; 酒井 政道; 平塚 信之
粉体および粉末冶金,
巻：59,
号：3,
開始ページ：131,
終了ページ：136, 2012年03月,
［査読有り］We have established the preparation process of hexagonal U-type ferrites Ba4Me2Fe36O60 (Me = Co, Ni, Mg) and investigated their crystal structure and magnetic properties. The U-type ferrite single phase was not fabricated by using a conventional ceramic synthesis process which comprises two-steps: calcination and sintering. We have found that the U-type ferrites single phase can be obtained by a one-step sintering method that skips the calcination process. The single phase of the U-type ferrite was formed at a very narrow temperature at about 1250 °C. The values of saturation magnetization and the Curie temperature of Co2U ferrite were higher than those of Co2Z ferrite. Initial permeability of Co2U ferrite has a higher value than those of Ni2U and Mg2U ferrites. The U-type ferrite has a great potential for high frequency magnetic materials.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.59.131DOI ID：10.2497/jjspm.59.131,
ISSN：0532-8799,
SCOPUS ID：84880563658 Magnetic property of pyrolytic carbon prepared on diamond powder in applied magnetic field K. Kamishima; T. Tokue; D. Miyata; Y. Sato; F. Kadonome; T. Noda; K. Kakizaki; N. Hiratsuka; Y. Imanaka; T. Takamasu
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS,
巻：324,
号：6,
開始ページ：1106,
終了ページ：1111, 2012年03月,
［査読有り］,
［筆頭著者, 責任著者］We have prepared pyrolytic carbon samples from triethylamine on diamond powder in applied magnetic field of 6 T and investigated their magnetic properties. A ferromagnetic sample was obtained from the pyrolysis products even at room temperature, with spontaneous magnetization of 6.4 A m(2)/kg at 300 K, which is twice as large as that of the sample prepared without diamond powder. Therefore, the diamond powder seems to promote the formation of a three-dimensional ferromagnetic structure in pyrolytic carbon. (C) 2011 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.jmmm.2011.10.042DOI ID：10.1016/j.jmmm.2011.10.042,
ISSN：0304-8853,
Web of Science ID：WOS:000298864100035 Formation of Flat, and Homogeneous Surfaces of Organized Molecular Films of Three-armed Polymerizable Amphiphiles with Metal-Scavenging Properties. A. Fujimori; M. Taguchi; S. Hakozaki; K. Kamishima; B. Ochiai
Langmuir,
巻：28,
開始ページ：10830,
終了ページ：10837, 2012年,
［査読有り］英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1021/la301126yDOI ID：10.1021/la301126y ゾルゲル自己燃焼法により作製したナノニッケルフェライト粒子の低温生成プロセスの解明および磁気特性 平塚 信之; 神野 恭平; 神島 謙二; 柿崎 浩一; 石丸 雄大; 酒井 政道
粉体および粉末冶金,
巻：58,
号：6,
開始ページ：334,
終了ページ：341, 2011年06月,
［査読有り］Nano-crystalline NiFe2O4 (NF) powder was prepared by a sol-gel auto-combustion method. Its crystal structure, morphology, particle size and magnetic properties were investigated and the formation process of nano-crystalline NF was elucidated. The as-dried Ni-Fe precursor (Ni/Fe=0.5) was calcined in air at 200-800°C for 4 hours. γ-Fe2O 3 powder was formed at about 210°C by the self-combustion of the gel, and was maintained at 200-400°C. Singlephase NF sample was obtained by being calcined at 600-800 °C. The NF particles were of nano-crystalline with crystallite diameters of 68.2-94.3 nm which were determined by the use of Scherrer equation for XRD peak broadening and the observation of TEM images. The sample calcined at 200 °C had a magnetization value of 44emu/g, which was lower than that of bulk γ-Fe2O3 (70 emu/g) because of a lot of vacancies at octahedral sites. Magnetization was increased gradually with increasing calcination temperature, and reached to the maximum value of 46 emu/g for the samples calcined at 700 and 800°C, which was in agreement with the magnetization of the bulk NF sample. Coercivity was decreased with increasing calcination temperature.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.58.334DOI ID：10.2497/jjspm.58.334,
ISSN：0532-8799,
SCOPUS ID：80052733699 強磁場中熱分解法によって作製した炭素系強磁性体の結晶構造および磁気特性 徳江 将; 神島 謙二; 宮田 大資; 佐藤 佑樹; 柿崎 浩一; 平塚 信之; 今中 康貴; 高増 正
粉体および粉末冶金,
巻：58,
号：3,
開始ページ：176,
終了ページ：180, 2011年03月,
［査読有り］We have prepared the carbon-based ferromagnets by pyrolytic method under high magnetic field and investigated their crystal structure and magnetic properties. The crystal structure was measured by the synchrotron X-ray diffraction experiment. The diffraction peak of a diamond was observed for the ferromagnetic samples. Thus, the carbon-based ferromagnet can be attributed to the ferromagnetic ordering of radical spins generated by defects in the diamond structure. And, the diffraction peak of a diamond of the ferromagnetic samples increased with the applied magnetic field in sample preparation. Therefore, the magnetic field may help to form a three dimensional ferromagnetic structure in the carbon-based ferromagnet. The highest magnetization was 3.0 emu/g at 300 K for the sample prepared under magnetic field at 6 T.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.58.176DOI ID：10.2497/jjspm.58.176,
ISSN：0532-8799,
SCOPUS ID：79958732198 Crystallographic and magnetic properties of Cu2X, Co2X, and Ni2X hexaferrites Kenji Kamishima; Nobuyuki Hosaka; Koichi Kakizaki; Nobuyuki Hiratsuka
JOURNAL OF APPLIED PHYSICS,
巻：109,
号：1,
開始ページ：013904 1-5, 2011年01月,
［査読有り］,
［筆頭著者, 責任著者］We have investigated the synthesis conditions and the magnetic properties of X-type hexagonal ferrites. It is found that Ba2Cu2Fe28O46 (Cu2X), Ba2Co2Fe28O46 (Co2X), and Ba2Ni2Fe28O46 (Ni2X) ferrites can be synthesized at a sintering temperature of 1250 degrees C. The x-ray diffraction patterns for Cu2X, Co2X, and Ni2X samples are in good agreement with the pattern calculated from the atomic coordinates for Ba2Fe30O46 (Fe2X), where two diffraction peaks at Q=2.24 and 2.30 angstrom(-1) are clearly observed in contrast with other M-, W-, Y-, and Z-types hexagonal ferrites. It is also found that the low-temperature spontaneous magnetizations of Cu2X, Co2X, and Ni2X ferrites are 47.5 mu(B)/f.u., 43.4 mu(B)/f.u., and 43.2 mu(B)/f.u., respectively. The cation distributions for Cu2X, Co2X, and Ni2X are discussed within the model of a Neel-type collinear ferrimagnetic structure. (C) 2011 American Institute of Physics. [doi:10.1063/1.3527933]
AMER INST PHYSICS, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1063/1.3527933DOI ID：10.1063/1.3527933,
ISSN：0021-8979,
Web of Science ID：WOS:000286219300078 遷移金属置換六方晶X型フェライトの作製および磁気特性 保坂 伸幸; 神島 謙二; 柿崎 浩一; 平塚 信之
粉体および粉末冶金,
巻：57,
号：12,
開始ページ：809,
終了ページ：813, 2010年12月,
［査読有り］The conventional synthesis of ferrite compounds consists of two-steps sintering processes. The first process is calcination to produce precursor of a desired ceramic object, and the second is to obtain the desired object. However, it was difficult to prepare X-type hexaferrite (Ba2Me 2+2Fe28O46· Me2X, Me = Co, Ni, Cu, Zn) samples by this method. Two-steps sintering of these samples resulted in formation of spinel, M and W-type ferrite phases. We have found that Me2X can be obtained by a one-step sintering method that skipped the calcination process. When this method is applied, the temperature range of Me2X formation was very narrow and about 1250°C. We measured the saturation magnetization at 2 K and room temperature, and examined the Curie temperatures Of Me2X samples produced by this method. These magnetic properties for Me2X samples relatively resemble those of MeFe 2O4 spinel ferrites, which suggests that Me2+ cations are distributed in spinel blocks in the Me2X crystal structure.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.57.809DOI ID：10.2497/jjspm.57.809,
ISSN：0532-8799,
SCOPUS ID：79953296296 マルチフェロイックCoFe2O4 - BaTiO3 複合材料における磁気電気効果 多田 晴香; 神島 謙二; 柿崎 浩一; 酒井 政道; 平塚 信之
粉体および粉末冶金,
巻：57,
号：11,
開始ページ：716,
終了ページ：721, 2010年11月,
［査読有り］Co1-xFe2+xO4-2BaTiO3 (x = 0,0.1 and 0.2) samples were prepared by using a conventional ceramic method. X-ray diffraction (XRD) and electron probe micro analysis (EPMA) measurements were done on these samples and we confirmed that cobalt ferrite and BaTiO3 components were clearly separated in the composites. The samples exhibited both ferroelectric and ferromagnetic properties. This indicates the samples were multiferroic materials. The resistivity was increased with x, whereas the tetragonality of BaTiO3 was decreased with x. While a sample with x = 0.1 had the highest permittivity of 522, samples with x = 0 and 0.2 had lower permittivity, which may have been caused by leakage current and deterioration of the ferroelectricity of BaTiO3, respectively. This same sample with x = 0.1 also exhibited the highest ME coefficient of 0.2 mV/cm Oe. We expect that improved permittivity will lead to a higher ME coefficient.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.57.716DOI ID：10.2497/jjspm.57.716,
ISSN：0532-8799,
SCOPUS ID：79951526177 Sr, Cu複合置換Ca3Co4O9+δの熱電特性 上垣外 直也; 神島 謙二; 柿崎 浩一; 平塚 信之
粉体および粉末冶金,
巻：57,
号：4,
開始ページ：237,
終了ページ：241, 2010年04月,
［査読有り］Ca3-xSrxCuyO9+δ (x = 0, 0.1, 0.3
y = 0, 0.05, 0.1 ) samples were prepared by using a conventional ceramic method. The crystal structure, bulk density and thermoelectric properties of the samples were investigated. In the X-ray diffraction patterns of the samples sintered at 1100°C, the single phase of Ca3Co 4O9+δ was obtained. Lattice constants were increased with x and y, which suggested that Sr and Cu were substituted for Ca and Co in the Ca3Co4O9+δ structure, respectively. The sample with x = 0.3 and y = 0.1 got the highest density because the grain size bacame small and the void was removed. The highest density sample had the highest conductivity in all samples. The Seebeck coefficient didn't change by substitution. As a result, the sample with x=0.3 and y = 0.1 had the highest power factor in all samples because of increase of the conductivity by substitution.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.57.237DOI ID：10.2497/jjspm.57.237,
ISSN：0532-8799,
SCOPUS ID：77954717675 Preparation of pyrolytic magnetic carbon under magnetic field Kenji Kamishima; Daisuke Miyata; Yki Sato; Takashi Tokue; Koichi Kakizaki; Nobuyuki Hiratsuka; Yasutaka Imanaka; Tadashi Takamasu
Journal of Physics: Conference Series,
巻：200,
号：SECTION 11, 2010年,
［査読有り］,
［筆頭著者, 責任著者］We have prepared pyrolytic carbon samples from triethylamine and investigated their magnetic properties. A ferromagnetic sample was obtained from the pyrolysis products even at room temperature, with spontaneous magnetization of 5 × 10-1 emu/g at 300 K. The magnetization was decreased with increasing temperature up to 500 K, but increased above 550 K. After this measurement, it was found that the magnetization at 300 K was changed to 6 × 10-1 emu/g. Another ferromagnetic sample has been also prepared by pyrolysis under high magnetic field of 2 Tesla. The spontaneous magnetization of this field-pyrolysis sample is 1.3 emu/g, which is twice as large as that of the above-mentioned sample prepared without magnetic field. Therefore, the magnetic field may help to form a ferromagnetic structure in pyrolytic carbon. © 2010 IOP Publishing Ltd.
研究論文（国際会議プロシーディングス）
DOI：https://doi.org/10.1088/1742-6596/200/11/112003Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=77957069803&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=77957069803&origin=inwardDOI ID：10.1088/1742-6596/200/11/112003,
ISSN：1742-6588,
eISSN：1742-6596,
SCOPUS ID：77957069803 六方晶X型フェライトBa2Ni2Fe28O46の結晶構造および磁気特性 保坂 伸幸; 山本 義久; 狩野 征爾; 何 浄沙; 稲田 宏; 神島 謙二; 柿崎 浩一; 平塚 信之
粉体および粉末冶金,
巻：57,
号：1,
開始ページ：41,
終了ページ：45, 2010年01月,
［査読有り］Ba2Ni2Fe28O46 (Ni2X) samples were prepared by using a conventional ceramic method. The crystal structure and magnetic properties of the samples were investigated. The X-ray diffraction patterns of the samples sintered at 1250 °C and 1300 °C were in agreement with the diffraction pattern simulated from the real space coordinates of Ba, Fe and O ions. The Curie temperature was found to be 478 °C, which was different from the Curie temperatures of M-type and Ni 2W-type hexaferrites. The single phase of X-type hexaferrite was obtained at 1250 °C, which suggests that the sintering processes should be carefully controlled for the synthesis of the X-type hexaferrite. The saturation magnetization of Ni2X-type hexaferrite was higher than that of M-type and W-type hexaferrite at room temperature. Whereas, the coercivity was lower than that of M-type hexaferrite.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.57.41DOI ID：10.2497/jjspm.57.41,
ISSN：0532-8799,
SCOPUS ID：77950506553 High frequency characteristic of elements substituted hexagonal ferrites
Nobuyuki Hiratsuka; Koichi Kakizaki; Kenji Kamishima
ASIAN CERAMIC SCIENCE FOR ELECTRONICS III AND ELECTROCERAMICS IN JAPAN XII, 巻：421-422, 開始ページ：541, 終了ページ：545, 2010年, ［査読有り］
The initial permeability mu ' (at 0.1 GHz) of Ba(3)Co(2)R(0.1)Fe(23.9)O(41) (x=0.1, R=Gd, Dy, Ho, Yb) samples is higher than that of the Co(2)Z ferrite without substitution. In particular, mu ' of Gd(3+) substituted Z-type ferrite sample (x=0.1) is the highest of all samples. The substituted sample of Ba(3)Co(2)Ti(x)Zn(x)Fe(24-2x)O(41) with x=0.85 has a maximum mu ' of 24, which is twice as large as that of the non-substituted sample with x=0. Ba(3)Co(2-2x) Li(x)Fe(24+x)O(41)(x=0-1.0) are also prepared. The sample with x=0 shows mu ' of 8 at 50MHz. The maximum mu ' is 24.5 at x=0.3. An apparent magnetic anisotropy constant K*, calculated by using H(A)* and M(S), decreases. Therefore, the decrease of the magnetic anisotropy contributes to the increase of mu '.
TRANS TECH PUBLICATIONS LTD, 英語, 研究論文（国際会議プロシーディングス）
ISSN：1013-9826, Web of Science ID：WOS:000279342100126
Magnetic and Electronic Properties of BaTiO3-(Ni,Cu,Zn)Fe2O4 Ceramic Composite: Reflection of Kepler Conjecture Kenji Kamishima; Yoshitaka Nagashima; Koichi Kakizaki; Nobuyuki Hiratsuka; Kowashi Watanabe; Hiroshi Naganuma
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN,
巻：78,
号：12,
開始ページ：124801 1-5, 2009年12月,
［査読有り］,
［筆頭著者, 責任著者］Ceramic composites [xNi(0.15)Cu(0.3)nZn(0.55)Fe(2)O(4)-(1-x)BaTiO3] were successfully prepared by a direct solid-state reaction of raw materials (BaCO3, CuO, alpha-Fe2O3, NiO, TiO2, and ZnO). The composites are so homogeneous that the ferrite and BaTiO3 grains do not react with each other. The x-dependent permeability and permittivity are found to obey Maxwell-Garnett effective medium theory, which suggests that the composites consist of ferrite particles with barium titanate medium. This model, however, starts to deviate from the experimental data at x = 0.75, and the roles of medium and inclusions seem to be exchanged. It can be qualitatively explained by the fact that geometrical close-packing of spheres is limited up to about 74 vol% (Kepler conjecture).
PHYSICAL SOC JAPAN, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1143/JPSJ.78.124801DOI ID：10.1143/JPSJ.78.124801,
ISSN：0031-9015,
Web of Science ID：WOS:000272985600045 磁場印加中熱分解による強磁性熱分解炭素の作製 神島 謙二; 宮田 大資; 佐藤 佑樹; 徳江 将; 柿崎 浩一; 平塚 信之; 今中 康貴; 高増 正
粉体および粉末冶金,
巻：56,
号：7,
開始ページ：456,
終了ページ：460, 2009年07月,
［査読有り］,
［筆頭著者, 責任著者］We have prepared pyrolytic carbon samples from triethylamine and investigated their yields and magnetic properties. Ferromagnetic samples were obtained from the pyrolysis products even at room temperature. The yield of the ferromagnetic sample was increased by setting a magnetic circuit on the pyrolysis chamber. The magnetic field seemed to affect the triethylamine vapor and then increased the yield and the magnetization. Also, the synchrotron X-ray diffraction experiments were performed for these pyrolytic carbon samples. Diffraction peaks of iron or iron oxides were not observed for the ferromagnetic samples, whereas the major diffraction peaks of the intermediate graphite-diamond (IGD) structure were observed for the ferromagnetic samples. The best magnetization sample also showed the diffraction peaks of the diamond-like-carbon structure. Therefore, the magnetic field may help to form a three-dimentional ferromagnetic structure in pyrolytic carbon.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.56.456DOI ID：10.2497/jjspm.56.456,
ISSN：0532-8799,
SCOPUS ID：70350074613 Mn-Ti置換Co2Z型フェライトの高周波磁気特性 江川 渉; 神島 謙二; 柿崎 浩一; 平塚 信之
Journal of the Magnetics Society of Japan,
巻：33,
号：3,
開始ページ：222,
終了ページ：226, 2009年05月,
［査読有り］Ba
3Co
2Mn
0.5xTi
0.5xFe
24-xO
41 (x=0-0.6) samples were prepared by using a conventional ceramic method. The samples had a the single crystallographic phase of hexagonal Z-type ferrite, which suggests that Fe
3+ ions are replaced by Mn
2+ and Ti
4+ ions. Substituted samples of Ba
3Co
2Mn
0.5xTi
0.5xFe
24-xO
41 with x=0.4 had a maximum μ' of 25.7 and a μ'×f
r of 17.6 GHz. The M-T curves exhibited an anomalous drop below the Curie temperature, which reflects the change from in-plane magnetic anisotropy to uniaxial anisotropy with increasing temperature. The temperature of the anomalous drop rose from 533 K to 559 K due to the substitution. This resulted in an improvement of μ' and μ'×f
r.
The Magnetics Society of Japan, 日本語
DOI：https://doi.org/10.3379/msjmag.0903RB8029DOI ID：10.3379/msjmag.0903RB8029,
ISSN：1882-2924,
CiNii Articles ID：10025969736,
CiNii Books ID：AA12297999 Co置換Biフェライト薄膜の室温での強誘電性および磁気特性 永沼 博; 三浦 淳; 神島 謙二; 柿崎 浩一; 平塚 信之; 安藤 康夫; 岡村 総一郎
日本磁気学会誌,
巻：33,
開始ページ：237,
終了ページ：241, 2009年,
［査読有り］日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.3379/msjmag.0903RC8081DOI ID：10.3379/msjmag.0903RC8081 ダブルペロブスカイト型Nb置換Sr2FeMoO6の熱電特性 菱沼 隼; 神島 謙二; 柿崎 浩一; 平塚 信之
粉体および粉末冶金,
巻：55,
号：12,
開始ページ：827,
終了ページ：830, 2008年12月,
［査読有り］Sr2FeMo1-xNbxO6 (x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) samples were prepared by a conventional ceramic method. The samples were sintered in 3 %H2/N2 gas at 1100°C for 6 hours. Analysis of the X-ray data shows that the samples are of single phase in double perovskite. The magnetization and the conductivity values are found to decrease with increasing x. Whereas, the Seebeck coefficient is found to increase with respect to x in all compounds.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.55.827DOI ID：10.2497/jjspm.55.827,
ISSN：0532-8799,
SCOPUS ID：62649149876 Annealing temperature dependences of ferroelectric and magnetic properties in polycrystalline co-substituted BiFeO3 films Hiroshi Naganuma; Jun Miura; Mitsumasa Nakajima; Hiromi Shima; Soichiro Okamura; Shintaro Yasui; Hiroshi Funakubo; Ken Nishida; Takashi Iijima; Masaki Azuma; Yasuo Ando; Kenji Kamishima; Koichi Kakizaki; Nobuyuki Hiratsuka
Japanese Journal of Applied Physics,
巻：47,
号：9 PART 2,
開始ページ：7574,
終了ページ：7578, 2008年09月,
［査読有り］Multiferroic Co-substituted BiFeO3 films were fabricated by chemical solution deposition method followed by post deposition annealing at various temperatures. The substitution of cobalt of B-sites for iron in BiFeO3 was promoted at relatively high temperatures. The B-site substitution by cobalt promoted increases in saturation magnetization and spontaneous magnetization. By substitution, leakage current density was suppressed in a high-electric-field region, and ferroelectric hysteresis (P-E) loops became measurable even at room temperature. The optimal annealing temperature for the coexistence of a high remanent polarization and a high remanent magnetization was 923 K having a high B-site substitution ratio of cobalt. © 2008 The Japan Society of Applied Physics.
研究論文（学術雑誌）
DOI：https://doi.org/10.1143/JJAP.47.7574Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=55149103742&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=55149103742&origin=inwardDOI ID：10.1143/JJAP.47.7574,
ISSN：0021-4922,
eISSN：1347-4065,
SCOPUS ID：55149103742 (Ni,Cu,Zn)Fe2O4-BaTiO3 共存材料の構造および物性 永島 義崇; 神島 謙二; 柿崎 浩一; 平塚 信之; 永沼 博; 岡村 総一郎
Journal of the Magnetics Society of Japan,
巻：32,
号：3,
開始ページ：250,
終了ページ：253, 2008年05月,
［査読有り］日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.3379/msjmag.32.250DOI ID：10.3379/msjmag.32.250 Ferroelectric and magnetic properties of multiferroic BiFeO3 based composite films Hiroshi Naganuma; Tomosato Okubo; Kenji Kamishima; Koichi Kakizaki; Nobuyuki Hiratsuka; Soichiro Okamura
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control,
巻：55,
号：5,
開始ページ：1051,
終了ページ：1055, 2008年05月,
［査読有り］英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1109/TUFFC.2008.755DOI ID：10.1109/TUFFC.2008.755 包接構造を有するスピネルフェライトのトンネル型磁気抵抗効果 池之谷 考志; 神島 謙二; 柿崎 浩一; 平塚 信之
粉体および粉末冶金,
巻：54,
号：6,
開始ページ：451,
終了ページ：454, 2007年06月,
［査読有り］SiO2-coated Fe3O4 samples were prepared by the sol-gel processing with several reaction time conditions. The samples were sintered in vacuum at 1000°C for 2 hours. MR ratio became the maximum of 3.6% for 12.9 vol.% SiO2 sample. This value is large compared with that of Fe3O4 reported before. The magnetization and magnetoresistance are saturated at the same magnetic field of about 4 kOe, which suggests that the MR effect is caused by magnetic scattering.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.54.451DOI ID：10.2497/jjspm.54.451,
ISSN：0532-8799,
SCOPUS ID：34548158406 Li置換Co2Z六方晶フェライトの高周波磁気特性 中根 純一; 神島 謙二; 柿崎 浩一; 平塚 信之
粉体および粉末冶金,
巻：54,
号：4,
開始ページ：232,
終了ページ：235, 2007年04月,
［査読有り］Z-type hexagonal ferrite samples with Ba3Co 2-2xLixFe24+xO41 (x = 0∼ 1.0) were prepared from stoichiometric mixtures of BaCO3, CoO, Li 2Co3 and α-Fe2O3, by calcinning at 1250°C and then sintering at 1275°C. The single phase of the Z-type was confirmed for the crystal structure of these samples with x=0∼0.5 by X-ray diffraction analysis. The sample with x = 0 showed μ' of 8 at 50MHz. The maximum μ' was 24.5 at x = 0.3. The Snoek's product of μ' × fr was 9G Hz at x = O and then increased to 15 GHz at x = 0.1-0.3. The bulk density took a maximum at x = 0.3, and the coercivity had a minimum at x = 0.3. Therfore, high frequency properties of Co2Z ferrite are specifically improved by the Li+-Fe3+ ions substitution with x=0.3.
日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.54.232DOI ID：10.2497/jjspm.54.232,
ISSN：0532-8799,
SCOPUS ID：34547285674 Synchrotron X-ray diffraction for pyrolytic magnetic carbon K. Kamishima; T. Noda; F. Kadonome; K. Kakizaki; N. Hiratsuka
Journal of Magnetism and Magnetic Materials,
巻：310,
号：2 SUPPL. PART 2, 2007年03月,
［査読有り］,
［筆頭著者, 責任著者］We have prepared pyrolytic carbon samples from triethylamine and investigated their magnetic and crystallographic properties. The magnetic property depends on pyrolysis temperatures. A ferromagnetic sample with M = 5 × 10- 1 emu / g was obtained from the pyrolysis products even at room temperature. The synchrotron X-ray diffraction experiments were performed for the pyrolytic carbon samples in order to see the crystal structure of ferromagnetic samples. Diffraction peaks of iron or iron oxides were not observed for the ferromagnetic samples, whereas the major diffraction peak of the intermediate graphite-diamond (IGD) structure was clearly observed for ferromagnetic and nonmagnetic samples. Therefore, the IGD structure is not the direct cause of ferromagnetism. The ferromagnetism may be related to the graphite-like structure. © 2006 Elsevier B.V. All rights reserved.
研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.jmmm.2006.10.325Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=33847251680&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=33847251680&origin=inwardDOI ID：10.1016/j.jmmm.2006.10.325,
ISSN：0304-8853,
SCOPUS ID：33847251680 Fine structures and magnetic properties of FeCo granular thin films with plasma polymerized (C4F8)n matrix K. Kakizaki; S. Yasoshima; K. -K. Choi; K. Kamishima; N. Hiratsuka
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS,
巻：310,
号：2,
開始ページ：E870,
終了ページ：E872, 2007年03月,
［査読有り］In this paper a method for polymerization of fluorocarbon gas in argon plasma to obtain a novel granular structure was reported. We prepared granular films where FeCo fine particles were distributed in plasma-polymerized. uorocarbon matrix by a facing-targets RF magnetron sputtering method, and investigated the correlation between their structures and magnetic properties. The magnetization of the films prepared with the partial pressure of fluorocarbon gas between 0 and 1.0 mTorr decreased linearly, because the FeCo content in a unit volume of a. lm decreased when a polymerized material was used as the matrix. However, the coercivity of the films decreased drastically with increasing the partial pressure of fluorocarbon gas above 0.4 mTorr. This is because the magnetic anisotropy of FeCo particles is decreased by the decrease of grain size. It was confirmed by a TEM observation that the FeCo-(C4F8)(n) films had the granular structure which was constituted by the very fine FeCo particles and the plasma-polymerized fluorocarbon matrix. For the film deposited at the partial pressure of fluorocarbon gas of 0.4 mTorr, the size of FeCo magnetic particles is about 20 nm. On the other hand, the size of FeCo particles is decreased to about 8 nm when the. lm deposited at the partial pressure of fluorocarbon gas of 0.8 mTorr and its distribution is small. (C) 2006 Published by Elsevier B. V.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/j.mmm.2006.11.133DOI ID：10.1016/j.mmm.2006.11.133,
ISSN：0304-8853,
Web of Science ID：WOS:000247720400422 金属元素置換Ｍ型バリウムフェライトの高周波磁気特性 宮田 謙一; 神島 謙二; 柿崎 浩一; 平塚 信之
日本応用磁気学会誌,
巻：30,
号：3,
開始ページ：383,
終了ページ：386, 2006年,
［査読有り］Co-Zn-Ti substituted M-type barium ferrites of BaCo
xTi
xFe
12-2xO
19 (x = 1−3 ) and BaCo
1.1Zn
yTi
1.1+yFe
9.8-2yO
19 (y = 0−1.0) were prepared by a powder metallurgy method. Their characteristics were examined by using an X-ray diffractometer, a vibration sample magnetometer (VSM), a vector impedance analyzer, and a scanning electron microscope. When Fe ions of BaFe
12O
19 were replaced with Co-Ti ions, the magnetic anisotropy and coercivity decreased. As a result, the initial permeability increased to 27 for a sample with x = 1.15. Zn-Ti ions were also substituted for Fe ions in BaCo
1.1Ti
1.1Fe
9.8O
19. When the amount of substitution (y) was 0.4 in BaCo
1.1Zn
yTi
1.1+yFe
9.8-2yO
19 (y = 0−1.0), the initial permeability at 10 MHz had a very high value of about 40. The reason for this may be that the coercivity becomes small as a result of the growth of the crystal particles and the decrease in the anisotropic magnetic field.
The Magnetics Society of Japan, 日本語
DOI：https://doi.org/10.3379/jmsjmag.30.383DOI ID：10.3379/jmsjmag.30.383,
ISSN：0285-0192,
CiNii Articles ID：130004479050 軟磁性フェロックスプラナ型フェライトの高周波磁気特性 松浦 準; 河野 健二; 神島 謙二; 柿崎 浩一; 平塚 信之
粉体および粉末冶金,
巻：53,
号：3,
開始ページ：268,
終了ページ：272, 2006年,
［査読有り］Y-type (Ba2Zn2Fe12O22
Y), M-type (BaCo1.1Ti1.1Fe9.8O19
M CT) and mixture of these hexagonal ferrites (Y+xM CT
x = 0-3) were prepared by the conventional solid-state reaction approach. Samples were made with BaCO3, ZnO, CoO, TiO2 and α-Fe2O3 as starting materials. The frequency dependence of the initial permeability of all samples was measured using an impedance analyzer (HP4291B). The initial permeability of Ba3Zn 2Co1.1Ti1.1Fe21.8O41 (x=1) was 23 (at 100MHz), which is the highest value in this study and the Snoek's product of this sample has been reached to 14.7 GHz. This value is twice larger than that of Zn2Y. The detailed analysis of frequency dependent permeability curves for these samples strongly suggests that this enhancement of the Snoek's product is due to the change of magnetic anisotropy caused by the substitution of Co2+ and Ti4+ ions for Fe3+ ions.
Funtai Funamtsu Yakin Kyokai/Japan Soc. of Powder Metallurgy, 日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.53.268DOI ID：10.2497/jjspm.53.268,
ISSN：0532-8799,
SCOPUS ID：33745017686 Levitation mechanism of a single steel ball under moderate magnetic fields provided by a Ne-Fe-B ring magnet M Sakai; Y Takabayashi; K Sugawara; T Shibayama; Y Shimomura; T Orikasa; K Kamishima; N Hirastuka
JOURNAL OF APPLIED PHYSICS,
巻：97,
号：8, 2005年04月,
［査読有り］Mechanism for magnetic levitation of a steel ball in a plastic box [S. Sasaki, I. Yagi, and M. Murakami, J. Appl. Phys. 95, 2090 (2004)] was investigated quantitatively based on measurement of the magnetic moments of the steel ball and ring magnet used in levitation experiment. The two-dimensional potential energy calculated in terms of magnetic dipole-dipole interactions gives rise to a stable equilibrium position approximately in agreement with the levitating position observed in our study. The role of the diamagnetic characteristic of the plastic plates was also discussed quantitatively. (C) 2005 American Institute of Physics.
AMER INST PHYSICS, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1063/1.1870096DOI ID：10.1063/1.1870096,
ISSN：0021-8979,
Web of Science ID：WOS:000228729500071 Cu系フェライトの磁気抵抗効果 佐藤 桂司; 神島 謙二; 柿崎 浩一; 平塚 信之
粉体および粉末冶金,
巻：51,
号：9,
開始ページ：708,
終了ページ：712, 2004年,
［査読有り］Polycrystalline Cu1-xFe2+xO4 (x=0, 0.25, 0.50, 0.75, 0.90) samples with spinel structure were prepared by the conventional ceramic process. The samples were sintered in N2 at 1100∼1400°C for 2 hours. The resistivity of all the samples is in 10-2 ∼10Ωcm, which is low as a ferrite. This originates in the hopping conduction between Cu1+ and Cu2+, and between Fe2+ and Fe3+ in all the samples. MR ratio at room temperature in Cu0.50Fe2.50O4 became maximum 10.4%. This value is large twice compared with that of Fe3O 4 reported before. The curves of MR and magnetization of Cu 0.50Fe2.50O4 have correlation, in which resistance decreases as magnetization increases. The MR effect is coused by magnetic scattering.
Journal of the Japan Society of Powder and Powder Metallurgy, 日本語, 研究論文（学術雑誌）
DOI：https://doi.org/10.2497/jjspm.51.708DOI ID：10.2497/jjspm.51.708,
ISSN：0532-8799,
SCOPUS ID：10444265924 Pressure Induced Magnetic Transition of Mn3Ga 1-xAlxC Kenji Kamishima; Tsuneaki Goto; Tatsuji Sasaki; Takeshi Kanomata; Toshiya Inami
Journal of the Physical Society of Japan,
巻：71,
号：3,
開始ページ：922,
終了ページ：926, 2002年03月,
［査読有り］,
［筆頭著者, 責任著者］We have measured the magnetization of Mn3Ga1-xAl xC with x = 0, 0.01 and 0.02 under pressure up to 1.25 GPa. A magnetic transition from an antiferromagnetic (AFM) to an intermediate (IM) state with spontaneous magnetization is observed under pressure. We have determined the phase diagram in the pressure-temperature plane. The application of pressure increases the magnetization in the ferromagnetic (FM) phase for all these compounds. We have also measured the thermal expansion of Mn 3Ga0.97Al0.03C. It is consistent with the pressure effects on the magnetization and suggests the magnetic contribution to the thermal expansion as ωmFM < ω m1M < ωmAFM. Neutron diffraction experiments were performed on Mn3Ga0.95Al 0.05C. Bragg peaks corresponding to an antiferromagnetic component were observed in the IM state. It is highly possible that the IM state has a canted ferromagnetic structure.
研究論文（学術雑誌）
DOI：https://doi.org/10.1143/JPSJ.71.922Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=0036250879&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=0036250879&origin=inwardDOI ID：10.1143/JPSJ.71.922,
ISSN：0031-9015,
SCOPUS ID：0036250879 Itinerant-electron metamagnetism and magneto-volume effects in Lu(Co1-xAlx)2 Laves phase compounds T Yokoyama; H Saito; K Fukamichi; K Kamishima; T Goto; H Yamada
JOURNAL OF PHYSICS-CONDENSED MATTER,
巻：13,
号：41,
開始ページ：9281,
終了ページ：9300, 2001年10月,
［査読有り］The itinerant-electron metamagnetic transition (MT) and the effects of hydrostatic pressure on the critical transition field B-C of the MT, on the spontaneous magnetization M-S and on the Curie temperature T-C have been investigated for well homogenized Lu(Co1-xAlx)(2) Laves phase compounds. The critical field B-C decreases with increasing x, maintaining a linear relationship with the inverse susceptibility at the temperature where the susceptibility exhibits a maximum value, chi (-1) (T-max). On applying pressure, the magnetization M of the ferromagnetic compound with x = 0.100 is drastically decreased at a critical pressure, resulting in a paramagnetic state. In addition, the metamagnetic transition from the paramagnetic to the ferromagnetic state is induced by applying an external magnetic field.
The effect of pressure on the Curie temperature T-C is extremely large and negative in the vicinity of the critical concentration for the onset of ferromagnetism. The pressure coefficient of the Curie temperature, partial derivative InTC/partial derivativeP, is much larger than that of the spontaneous magnetization, partial derivative InMS/partial derivativeP, below x = 0.150. These results can be explained by the theory for itinerant ferromagnets having a negative coefficient b of the fourth-order term in the Landau expansion. The Landau expansion coefficients estimated from the experimental results are in accord with the theories. From these estimated values, it is concluded that the magneto-volume effect decreases the critical transition field B-C. It has been confirmed that the results for Lu(Co1-xAlx)(2) are very much analogous to those for Lu(Co1-xGax)(2).
IOP PUBLISHING LTD, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1088/0953-8984/13/41/317DOI ID：10.1088/0953-8984/13/41/317,
ISSN：0953-8984,
CiNii Articles ID：80012650220,
Web of Science ID：WOS:000172033800021 Investigation of a strong titanium alloy KS15-5-3 and the application to a high pressure apparatus for magnetization measurements K. Kamishima; M. Hagiwara; H. Yoshida
Review of Scientific Instruments,
巻：72,
号：2,
開始ページ：1472,
終了ページ：1476, 2001年02月,
［査読有り］,
［筆頭著者, 責任著者］A β titanium alloy of Ti-15Mo-5Zr-3Al (KS15-5-3) is presented as a new material for experimental apparatus to be used at extreme conditions of high pressure, low temperature, and high magnetic field. The material has a tensile strength of 1760 MPa at room temperature and is found to be a Pauli paramagnet with nearly temperature-independent magnetization M/B∼3 × 10-2 (mJ/Tg)/T, except for T
TC. To illustrate the performance of this cell, we present experimental results on a one-dimensional alternating bond antiferromagnet with S = 1:Ni(333-tet)(μ-NO2)(ClO4) [333-tet denotes N,N′-bis(3-aminopropyl)-1,3-propanediamine]. © 2001 American Institute of Physics.
研究論文（学術雑誌）
DOI：https://doi.org/10.1063/1.1337074
Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=0035247169&origin=inward
Scopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=0035247169&origin=inward
DOI ID：10.1063/1.1337074, ISSN：0034-6748, SCOPUS ID：0035247169 Giant magnetoresistance in the intermetallic compound Mn3GaC K Kamishima; T Goto; H Nakagawa; N Miura; M Ohashi; N Mori; T Sasaki; T Kanomata
PHYSICAL REVIEW B,
巻：63,
号：2,
開始ページ：024426 1-6, 2001年01月,
［査読有り］,
［筆頭著者, 責任著者］We have measured the transverse resistance of an intermetallic compound Mn3GaC in pulsed high magnetic fields up to 25 T. Giant magnetoresistance is observed due to the field-induced magnetic transition from the antiferromagnetic to the intermediate phase at low temperatures. The temperature dependence of magnetoresistance shows a dip at the Curie temperature. The dip can be explained using a simple model of de Gennes and Friedel based on magnetic critical scatterings. The normal Hall coefficient is found to show a striking change at the transition, suggesting that the giant magnetoresistance is caused by the change of the carrier concentration.
AMER PHYSICAL SOC, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1103/PhysRevB.63.024426DOI ID：10.1103/PhysRevB.63.024426,
ISSN：1098-0121,
eISSN：1550-235X,
Web of Science ID：WOS:000166382200050 Giant magnetovolume effect of CrTe
T Kanomata; Y Sugawara; T Kaneko; K Kamishima; HA Katori; T Goto
JOURNAL OF ALLOYS AND COMPOUNDS, 巻：297, 号：1-2, 開始ページ：5, 終了ページ：8, 2000年02月, ［査読有り］
The pressure change of the spontaneous magnetization sigma(s) of the itinerant electron ferromagnet CrTe has been determined in the ranges of hydrostatic pressure and temperature of 0-6.1 kbar and 4.2-70 K, respectively. The spontaneous magnetization decreases linearly with pressure at temperatures from 4.2 to 70 K. The values of d sigma(s)/dp and d In sigma(s)/dp at 4.2 K are found to be -0.92 emu g(-1) kbar(-1) and -1.2x10(-2) kbar(-1), respectively. (C) 2000 Elsevier Science S.A. All rights reserved.
ELSEVIER SCIENCE SA, 英語, 研究論文（学術雑誌）
ISSN：0925-8388, Web of Science ID：WOS:000084513000003
Decoupling of the magnetic ordering of the rare-earth and the Co sublattice in Er1-xYxCo2 compounds driven by substitution or pressure
R Hauser; E Bauer; E Gratz; H Muller; M Rotter; H Michor; G Hilscher; AS Markosyan; K Kamishima; T Goto
PHYSICAL REVIEW B, 巻：61, 号：2, 開始ページ：1198, 終了ページ：1210, 2000年01月, ［査読有り］
The thermodynamic and transport properties of the Er1-xYxCo2 system were studied in the concentration range 0.0 less than or equal to x less than or equal to 1.0: In this system, the first-order magnetic phase transition observed in ErCo2 at T-C = 32 K is related to the itinerant electron metamagnetism of the d subsystem (Co sublattice) driven by the onset of magnetic ordering within the Er sublattice. By employing magnetic, specific heat, thermal expansion, and resistivity measurements we show that in a limited concentration range x(cr') < x < x(cr) and pressure P-cr' < P < P-cr the itinerant Co sublattice orders magnetically at T-C(Co), which is lower than T-C(R) of the Er sublattice. This is referred either to a weakening of the effective molecular field acting on the Co sites owing to the yttrium subsititution or to a pressure-driven increase of the critical field necessary to induce a magnetic moment on the Co sites. On further increasing the yttrium concentration or the pressure only the Er sublattice exhibits long-range order. The theoretical calculations within the molecular field approximation are in agreement with the experimental magnetic x-T phase diagram of the Er1-xYxCo2 system and confirm the effect of a separate ordering of the magnetic sublattices with reasonable parameters used for the intrasublattice Er-Er and intersublattice Er-Co exchange interactions. A field-induced collapse of the Co moment, inverse itinerant electron metamagnetism, is well observable by magnetoresistance measurements at appropriate Values of concentration and external pressure. The existence of itinerant electron metamagnetism in the Co sublattice is found to be limited in temperature by T-0, a characteristic temperature which is sensitive to substitution and pressure.
AMER PHYSICAL SOC, 英語, 研究論文（学術雑誌）
ISSN：1098-0121, eISSN：1550-235X, Web of Science ID：WOS:000085760000056
Itinerant-electron metamagnetism of the Laves-phase compounds Lu(Co1-xGax)2 under high pressures with high magnetic fields
H Saito; T Yokoyama; K Fukamichi; K Kamishima; T Goto
PHYSICAL REVIEW B, 巻：59, 号：13, 開始ページ：8725, 終了ページ：8731, 1999年04月, ［査読有り］
Magnetic properties of the Laves phase compounds Lu(Co1-xGax)(2) (0.10 less than or equal to x less than or equal to 0.22) have been investigated under the duplicate conditions, i.e., high magnetic fields with high pressures. The pressure effect on the Curie temperature T-C is extremely large in the vicinity of x = 0.10, which is close to the critical concentration for the onset of ferromagnetism. The spontaneous magnetization M-S around x = 0.10 is drastically decreased and a paramagnetic state is induced by applying pressure. The paramagnetic state is changed into a ferromagnetic state by applying magnetic field, accompanied by a metamagnetic transition. The Landau coefficients up to the sixth-order terms of the magnetization for x = 0.10 were estimated from the experimental data. The pressure dependence of the critical transition field H-C for x = 0.10 is consistent with the results calculated from the obtained coefficients. For the compounds with x less than or equal to 0.15, the pressure coefficient of the spontaneous magnetization, partial derivative In M-S / partial derivative P, is much larger than the pressure coefficient of the Curie temperature, partial derivative In T-C / partial derivative P, implying that there is a peak of the density of state just below the Fermi energy. The variation of partial derivative In T-C / partial derivative In M-S as a function of x near the critical concentration of the onset of ferromagnetism can be explained by the theory for itinerant ferromagnets having a negative coefficient b, of the fourth-order term in the Landau expansion. [S0163-1829(99)02413-3].
AMER PHYSICAL SOC, 英語, 研究論文（学術雑誌）
ISSN：1098-0121, eISSN：1550-235X, Web of Science ID：WOS:000079754100064
Magnetic Properties of the 5f Itinerant Electron Metamagnet UCoAl underHigh Pressure Mushnikov N.V; T. Goto; K. Kamishima; H. Yamada; A.V. Andreev; Y. Shiokawa; A. Iwao; V. Sechovsky
Phys. Rev. B,
巻：59,
号：10,
開始ページ：6877,
終了ページ：6885, 1999年01月,
［査読有り］英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1103/PhysRevB.59.6877DOI ID：10.1103/PhysRevB.59.6877 Magnetization under high pressure in MnSi
C Thessieu; K Kamishima; T Goto; G Lapertot
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 巻：67, 号：10, 開始ページ：3605, 終了ページ：3609, 1998年10月, ［査読有り］
The magnetization M(H) has been measured in the weakly helimagnetic itinerant compound MnSi under high pressure up to 10.2 kbar and high magnetic field up to 9 Tesla. We interpret the simultaneous decrease under pressure of the saturated magnetization, p(s), and the Curie temper ature: T-c in the frame of the self-consistent renormalization theory (SCR) of spin fluctuations. From the analysis of the so-called Arrott-plot (H/p[H,T] versus p(2)[H,T]) and the respective volume dependence of p(s) and T-c, we estimate the evolution of the characteristic spin fluctua tion temperatures, T-0 and T-A when the system approaches its critical pressure, P-c = 15 kbar, corresponding to the disappearance of the long range magnetic order at T = 0.
PHYSICAL SOC JAPAN, 英語, 研究論文（学術雑誌）
ISSN：0031-9015, Web of Science ID：WOS:000076724400047
Field and pressure dependence of itinerant electrons metamagnetism in Er1-xYxCo2
AS Markosyan; R Hauser; M Galli; E Bauer; E Gratz; G Hilscher; K Kamishima; T Goto
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 巻：185, 号：2, 開始ページ：235, 終了ページ：237, 1998年06月, ［査読有り］
By substituting Y for Er in Er1-xYxCo2 the metamagnetic behaviour of the itinerant d subsystem vanishes beyond a critical concentration x(cr) approximate to 0.4. A decoupling of the common magnetic ordering of both magnetic sublattices is observed for x = 0.4 at ambient conditions and for x = 0.3 under pressure. When increasing the pressure beyond a critical value P-cr, only the R subsystem orders in both alloys, whereas the itinerant d sublattice stays disordered down to the lowest temperatures. (C) 1998 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0304-8853, Web of Science ID：WOS:000073909200016
Magnetic Behavior of Mn3GaC under High Magnetic Field and High Pressure Kenji Kamishima; Mikhail I. Bartashevich; Tsuneaki Goto; Makoto Kikuchi; Takeshi Kanomata
Journal of the Physical Society of Japan,
巻：67,
号：5,
開始ページ：1748,
終了ページ：1754, 1998年05月,
［査読有り］,
［筆頭著者, 責任著者］We have measured the magnetization and magnetostriction of Mn3GaC in pulsed high magnetic fields up to 37 T and the magnetization under steady magnetic field and pressure up to 0.82 GPa. Mn3GaC is antiferromagnetic (AF) at low temperatures. It exhibits successive transitions to an intermediate (I), to a ferromagnetic (F) and to a paramagnetic phase. The transition between the AF and I phases is first order and the others are second order. The transition temperature between the I and F phases does not change greatly with increasing magnetic field. At low temperatures, a metamagnetic transition from the AF to the I state is observed. Volume magnetostriction measurement at 4.2 K indicates that the volume is abruptly decreased by the metamagnetic transition and then gradually shrinks with increasing field. High pressure stabilizes the F phase and enhances the Mn moment.
研究論文（学術雑誌）
DOI：https://doi.org/10.1143/JPSJ.67.1748Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=0032337451&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=0032337451&origin=inwardDOI ID：10.1143/JPSJ.67.1748,
ISSN：0031-9015,
SCOPUS ID：0032337451 High-resolution, high-field magnetization measurement in the diluted antiferromagnet RbMncMg1-cF3: New application of pulsed high fields to adiabatic magnetization processes
Y Ajiro; T Asano; H Aruga-Katori; T Goto; K Koui; K Kamishima; H Ikeda
PHYSICA B, 巻：246, 開始ページ：222, 終了ページ：225, 1998年05月, ［査読有り］
Tremendously finely resolved magnetization anomalies are reported, for the first time, for pulsed high-field measurements up to 38 T, on the diluted antiferromagnet RbMncMg1-cF3. More than 60 regularly spaced peaks in dM/dB curve are classified into a series of higher harmonics up to sixth order and interpreted in terms of multiple spin flips in the nonequilibrium adiabatic process of the antiferromagnetically coupled Mn2+ dimer system. The result demonstrates an intrigueing potential of application of pulsed high fields to the dynamic magnetization process. (C) 1998 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0921-4526, Web of Science ID：WOS:000074665400045
High-field magnetization processes of quantum double spin chain systems KCuCl3, TlCuCl3 and NH4CuCl3
H Tanaka; W Shiramura; T Takatsu; B Kurniawan; M Takahashi; K Kamishima; K Takizawa; H Mitamura; T Goto
PHYSICA B-CONDENSED MATTER, 巻：246, 開始ページ：230, 終了ページ：233, 1998年05月, ［査読有り］
High-field magnetization processes of S = 1/2 double spin chain systems KCuCl3, TiCuCl3 and NH4CuCl3 have been measured up to 39 T at helium temperatures using single crystals. A transition from a singlet ground state with an excitation gap to a gapless magnetic state occurs at H-c similar to 20 and 6 T for KCuCl3 and TlCuCl3, respectively. The excitation gap Delta is evaluated as Delta/kappa(B) = 31.1 K for KCuCl3 and 7.5 K for TlCuCl3. Although the antiferromagnetic interactions in TlCuCl3 are stronger than those in KCuCl3, which can be seen from the slope of the magnetization curves above H-c, the excitation gap in TlCuCl3 is about a quarter of that of KCuCl3. In contrast to KCuCl3 and TlCuCl3, NH4CuCl3 has a gapless magnetic ground state. It is found that NH4CuCl3 undergoes five phase transitions in high magnetic fields. Two wide plateaus are observed at a quarter and three quarters of the saturation magnetization. (C) 1998 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0921-4526, Web of Science ID：WOS:000074665400047
Magnetovolume Effect of La0.7Sr0.3MnO3 T. Kanomata; N. Suzuki; K. Kamishima; T. Goto; H. Yoshida; T. Kaneko
Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu,
巻：7,
開始ページ：659,
終了ページ：661, 1998年,
［査読有り］The magnetization curves at 4.2 K of La0 7Sr0 3MnO3 are obtained under hydrostatic pressure up to 10.1 kbar by employing subtraction magnetometer. The saturation magnetization σ at 4.2 K increases with applied pressure and the pressure dependence of sg is nonlinear. Furthermore, the pressure derivative of the Curie temperature (Tc) of La0 7Sr0 3MnO3 is obtained from the result of measurement of temperature dependence of initial permeability at various pressures. The value of dTcJdp is found to be +0.13 KJkbar. © 1998, The Japan Society of High Pressure Science and Technology. All rights reserved.
英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.4131/jshpreview.7.659DOI ID：10.4131/jshpreview.7.659,
ISSN：1348-1940,
SCOPUS ID：85024742648 Magnetic phase diagram of CsNi1-xFexCl3: magnetization and specific heat
T Asano; Y Ajiro; M Mekata; K Kamishima; T Goto; HA Katori; K Katsumata
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 巻：177, 開始ページ：640, 終了ページ：642, 1998年01月, ［査読有り］
Magnetization and specific heat have been measured to determine the magnetic field versus temperature phase diagram of CsNi0.98Fe0.02Cl3. The obtained phase diagram is different from those of the pure CsNiCl3 with easy-axis anisotropy and of CsMnBr3 with strong easy-plane anisotropy, but has features of that predicted for weak easy-plane anisotropy by Plumer et al. A novel phase boundary suggested from neutron diffraction was found to be detectable by magnetization but not by specific heat. (C) 1998 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0304-8853, Web of Science ID：WOS:000072262000279
Pressure effect on spontaneous magnetization of Cr2Te3 and Cr5Te8
T Kanomata; Y Sugawara; K Kamishima; H Mitamura; T Goto; S Ohta; T Kaneko
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 巻：177, 開始ページ：589, 終了ページ：590, 1998年01月, ［査読有り］
The pressure change of the spontaneous magnetization sigma(s), at 4.2 K for Cr2Te3 and Cr5Te8 are measured by employing the subtraction magnetometer. The value of d sigma/dp for Cr2Te3 is -1.22 emu/g kbar. For Cr5Te8, the pressure derivative of sigma(s) is found to be almost zero. (C) 1998 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0304-8853, Web of Science ID：WOS:000072262000258
Instrument for high resolution magnetization measurements at high pressures, high magnetic fields and low temperaturesK. Koyama; S. Hane; K. Kamishima; T. Goto
Review of Scientific Instruments,
巻：69,
開始ページ：3009,
終了ページ：3014, 1998年01月,
［査読有り］An instrument has been developed for the first time that makes high resolution magnetization measurements at high pressures, high magnetic fields and low temperatures. The instrument consists of an extraction-type magnetometer, a nonmagnetic high pressure clamp cell and a 20 T superconducting magnet with a3He refrigerator and is able to precisely measure the magnetization of weakly magnetic materials. TiCu alloy with 3 wt % Ti is employed as a nonmagnetic material with high mechanical strength for the high pressure clamp cell. This apparatus can be used in the pressure range 0≤P≤13 kbar, the field range 0≤H≤200 kOe and the temperature range 0.5≤T ≤4.2 K. The resolution of the instrument is estimated to be ±0.002 emu. For demonstrating the ability of the instrument, the experimental results on a heavy fermion antiferromagnet Ce7Ni3is presented. © 1998 American Institute of Physics.
DOI：https://doi.org/10.1063/1.1149048DOI ID：10.1063/1.1149048,
ISSN：0034-6748,
SCOPUS ID：0001379634 Ground State and Energy Gap of Quantum Double Spin Chain System : KCuCl3 Family W. Shiramura; K. Takatsu; H. Tanaka; K; Takizawa; M; Takahashi; K. Kamishima; H. Mitamura; T. Goto
Journal of Magnetism and Magnetic Materials,
巻：177/181,
号：Pt.1,
開始ページ：693,
終了ページ：694, 1998年,
［査読有り］DOI：https://doi.org/10.1016/S0304-8853(97)00471-XDOI ID：10.1016/S0304-8853(97)00471-X,
ISSN：0304-8853 Effect of pressure on Magnetic Properties of Lu(Co1-xGax)2 Itinerant-electron Ferromagnetic Compounds H. Saito; T. Yokoyama; K. Fukamichi; K. Kamishima; H. Mitamura; T. Goto
Rev. Hight Pressure Sci. Technol.,
巻：7,
開始ページ：556,
終了ページ：558, 1998年
DOI：https://doi.org/10.4131/jshpreview.7.556DOI ID：10.4131/jshpreview.7.556,
ISSN：0917-639X Effects of alloying and pressure on metamagnetism of UCoAl
AV Andreev; L Havela; Sechovsky, V; MI Bartashevich; T Goto; K Kamishima
PHYSICA B, 巻：239, 号：1-2, 開始ページ：88, 終了ページ：94, 1997年08月, ［査読有り］
Doping by other d-metals in the Co sublattice and/or application of external pressure influences strongly the magnetic properties of 5f-band metamagnet UCoAl. Already 1-2% of Ru or Fe stabilise ferromagnetism, while the doping by Ni as well as the external pressure suppress the metamagnetism. The main role of the observed alloying and pressure effects can be attributed to the involvement of the 5f-ligand hybridisation in both the U 5f-moment formation and the 5f-5f exchange interactions. In many aspects UCoAl shows strong similarities to the 3d band metamagnets CoS2, YCo2 and LuCo2, which suggests an essentially same origin of field-induced phenomena in the both classes of materials.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0921-4526, Web of Science ID：WOS:A1997XV60900023
Magnetic behavior of Mn3Ga1-xAlxC under high magnetic field and high pressure K Kamishima; T Goto; T Kanomata
PHYSICA B,
巻：237,
開始ページ：561,
終了ページ：562, 1997年07月
Mn3GaC is antiferromagnetic (AF) below T-t similar to 160 K and ferromagnetic (F) above T-t. The application of pressure enhances the Mn moment in the F state and produces an intermediate state between the AF and F states. Mn3GaC shows a metamagnetic transition to the F state below T-t. From the transition fields, the electronic specific heat coefficient in the F state is estimated to be gamma = 43 mJ/K-2 mol, which is extremely large. The substitution of Al for Ga in Mn3GaC produces the same effect as the application of high pressure.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/S0921-4526(97)00246-9DOI ID：10.1016/S0921-4526(97)00246-9,
ISSN：0921-4526,
CiNii Articles ID：30003586541,
Web of Science ID：WOS:A1997XM23300196 Crystal lattice changes induced by magnetic field and helifan structure in holmium metal
H Ohsumi; K Tajima; N Wakabayashi; Y Shinoda; K Kamishima; T Goto
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 巻：66, 号：7, 開始ページ：1896, 終了ページ：1899, 1997年07月, ［査読有り］
An X-ray diffraction study has been made on holmium metal in a magnetic field at several temperatures. In most cases, the c-lattice parameter has been observed to change discontinuously with increasing magnetic field, corresponding to the appearance of various magnetic structures. The result or numerical calculations hy a self-consistent mean field method suggests that the effect of the helifan structure on the crystal lattice has been observed in a narrow range of magnetic field.
PHYSICAL SOC JAPAN, 英語
ISSN：0031-9015, Web of Science ID：WOS:A1997XP09400012
High-field magnetization processes of double spin chain systems KCuCl3 and TlCuCl3
W Shiramura; K Takatsu; H Tanaka; K Kamishima; M Takahashi; H Mitamura; T Goto
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 巻：66, 号：7, 開始ページ：1900, 終了ページ：1903, 1997年07月, ［査読有り］
High-field magnetization processes of S=1/2 double spin chain systems KCuCl3 and TlCuCl3 have been measured up to 39 T at 4.2 and 1.7 K for both systems and at 1.0 and 0.5 K for TlCuCl3 using single crystals. A transition from a singlet ground state with an excitation gap to a gapless magnetic state with finite susceptibility occurs at H-c similar to 20 T and 6 T for KCuCl3 and TlCuCl3, respectively. The critical field H-c depends on the external field direction due to the anisotropy of the g-factor. The excitation gap Delta is evaluated as Delta/k(B) = 31.1 K for KCuCl3 and 7.5 K for TlCuCl3. Although the antiferromagnetic interactions in TlCuCl3 are stronger than those in KCuCl3, which can be seen from the slope of the magnetization curves above H-c; the excitation gap in TlCuCl3 is about a quarter of that of KCuCl3. It is observed that the transition field H-c increases with increasing temperature.
PHYSICAL SOC JAPAN, 英語
ISSN：0031-9015, Web of Science ID：WOS:A1997XP09400013
Anomalous magnetic properties due to Co metamagnetism in Ce(Co1-xNix)5
MI Bartashevich; T Goto; K Koui; K Kamishima; AV Korolyov; AS Ermolenko
PHYSICA B, 巻：237, 開始ページ：487, 終了ページ：488, 1997年07月, ［査読有り］
The magnetization up to 120 T and 10 kbar and magnetostriction up to 40 T have been measured for single-crystalline Ce(Co1-xNix)(5) with x less than or equal to 0.3. The Co moment is in high moment state for CeCo5 and in low moment state for x greater than or equal to 0.1. A metamagnetic transition from the low to the high moment state can be induced by applying held up to 120 T for x = 0.1 and 0.2. The relations between the Co moment state and the magnetic characteristics are discussed.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0921-4526, Web of Science ID：WOS:A1997XM23300169
Magnetic phase transition of MnAs1-xSbx
O Nashima; T Suzuki; K Kamishima; T Goto; H Ido
PHYSICA B, 巻：237, 開始ページ：159, 終了ページ：161, 1997年07月, ［査読有り］
Magnetic properties and magnetovolume effects are investigated for MnAs1-xSbx, and all of the experimental data are found to be explained semi-quantitatively on the basis of the Bean-Rodbell model.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0921-4526, Web of Science ID：WOS:A1997XM23300057
Singlet ground state and energy gap in double spin chain system KCuCl3 family
H Tanaka; K Takatsu; W Shiramura; T Ono; T Kambe; K Kamishima; H Mitamura; T Goto
PHYSICA B, 巻：237, 開始ページ：120, 終了ページ：122, 1997年07月, ［査読有り］
Magnetic properties of S = 1/2 double spin chain systems KCuCl3 and TlCuCl3 have been investigated by susceptibility, high-field magnetization process and ESR measurements using single crystals. The present systems can be described as a Heisenberg spin ladder with an additional interaction. It is found that the susceptibilities of both the compounds exhibit broad maxima and decrease exponentially to zero with decreasing temperature. This result indicates that the ground slate of the present system is a spin singlet and there is a finite gap in the excitation spectrum. The transition to the magnetic state is clearly observed by the high-field magnetization process. ESR absorption due to the excitation from the singlet ground state to the excited state is observed for TlCuCl3.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0921-4526, Web of Science ID：WOS:A1997XM23300045
5f band metamagnetism in UCoAl: Effects of alloying and pressure
AV Andreev; L Havela; Sechovsky, V; MI Bartashevich; T Goto; K Kamishima
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 巻：169, 号：3, 開始ページ：229, 終了ページ：239, 1997年05月, ［査読有り］
We report on the results of magnetisation and susceptibility studies of the effects induced in the 5f band metamagnet UCoAl by doping with other elements and/or by application of external pressure. In majority of aspects UCoAl shows strong similarities to the 3d band metamagnets CoS2, YCo2 and LuCo2, which suggests an essentially same origin of field-induced phenomena in both the classes of materials. The main role of the observed alloying and pressure effects can be attributed to the involvement of the 5f-ligand hybridisation in both the U Sf-moment formation and the 5f-5f exchange interactions.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0304-8853, Web of Science ID：WOS:A1997XE34300001
Field-induced magnetic transition of Mn3GaC T Kanomata; M Kikuchi; T Kaneko; K Kamishima; MI Bartashevich; HA Katori; T Goto
SOLID STATE COMMUNICATIONS,
巻：101,
号：11,
開始ページ：811,
終了ページ：814, 1997年03月,
［査読有り］Field-induced transitions were studied in Mn3GaC in magnetic fields up to 370 kOe. The antiferromagnetic (AFM)-ferromagnetic (FM) field-induced transition is of the first order. The saturation magnetization sigma(s) at 4.2 K in the FM state is 75.0 emu g(-1) equivalent to 1.1 mu(B) per Mn atom. The decreasing rate of sigma(s) is rather smaller than that of the S = 1/2 Brillouin function. In the magnetostriction measurement of Mn3GaC, an abrupt volume contraction of -0.50% was found at the AFM-FM transition temperature. The result of the forced volume magnetostriction measurement shows that sigma(s) at 4.2 K increases with pressure. (C) 1997 Elsevier Science Ltd.
PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
DOI：https://doi.org/10.1016/S0038-1098(96)00737-5Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=0031096470&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=0031096470&origin=inwardDOI ID：10.1016/S0038-1098(96)00737-5,
ISSN：0038-1098,
SCOPUS ID：0031096470,
Web of Science ID：WOS:A1997WL29900006 Effects of external pressure on the 5f-band metamagnetism in UCoAl
AV Andreev; MI Bartashevich; T Goto; K Kamishima; L Havela; Sechovsky, V
PHYSICAL REVIEW B, 巻：55, 号：9, 開始ページ：5847, 終了ページ：5850, 1997年03月, ［査読有り］
UCoAl exhibits below 16 K anisotropic 5f-band metamagnetism induced by magnetic fields as low as similar to 1 T applied along the c axis of the hexagonal structure. No metamagnetic transition is observed in fields up to 40 T applied within the basal plane. The critical field of the metamagnetic transition B-c is composition dependent within the homogeneity range. The metamagnetic transition is found to be very sensitive to external pressure. The value of B-c increases with the rate dB(c)/dp=0.27 T/kbar, whereas the magnetization gained through the transition becomes reduced. The critical pressure of 24 kbar (corresponding to similar to 2% volume contraction) for disappearance of metamagnetism in UCoAl has been estimated. Relations of UCoAl to 3d-band metamagnets are discussed.
AMERICAN PHYSICAL SOC, 英語, 研究論文（学術雑誌）
ISSN：0163-1829, Web of Science ID：WOS:A1997WN21800063
The Haldane state in CsNiCl3 detected by magnetization measurements - Observation of quantum-classical crossover and the Valence Bond Solid state
T Asano; Y Ajiro; M Mekata; K Kamishima; K Koui; T Goto; M Furusawa; H Hori
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN, 巻：66, 号：2, 開始ページ：460, 終了ページ：465, 1997年02月, ［査読有り］
We have confirmed from susceptibility and magnetization measurements that the Haldane state really exists in 1D phase of CsNiCl3 which undergoes 3D ordering at T-N = 4.8 K. The observed susceptibility at low fields follows the predicted curve for the S = 1 quantum chain with energy gap (Delta/k(B) similar to 10 K) down to near T-N. A more definite evidence for the Haldane state is given by studying the effect of the nonmagnetic impurities, We haw revealed a real existence of S = 1/2 edge states characteristic of the Haldane state and further revealed a crossover from the quantum to classical regimes as a function of both temperature and field, The result is consistent with the model that at low temperatures (T < T-G Delta/k(B)) and low fields (H < H-G Delta/g mu(B)) the Haldane state is well defined to form the Valence-Bond-Solid while at high temperatures (T > \J\/k(B)) and high fields (H > H-G) the system is not in the Haldane state any more.
PHYSICAL SOC JAPAN, 英語, 研究論文（学術雑誌）
ISSN：0031-9015, Web of Science ID：WOS:A1997WR43200038
5f-band metamagnetism in UCoAl
L Havela; AV Andreev; Sechovsky, V; IK Kozlovskaya; K Prokes; P Javorsky; MI Bartashevich; T Goto; K Kamishima
PHYSICA B, 巻：230, 開始ページ：98, 終了ページ：101, 1997年02月, ［査読有り］
UCoAl is a 5f-band metamagnet characterized by a very low critical held B-c approximate to 0.8 T, which induces magnetization of 0.3 mu(B)/f.u. by a distinct transition. B-c increases with increasing temperature with the rate consistent with the reduced gamma-coefficient in the high-held state. B-c-values are also sensitive to stoichiometry and external pressure.
ELSEVIER SCIENCE BV, 英語, 研究論文（学術雑誌）
ISSN：0921-4526, Web of Science ID：WOS:A1997WW40300028
Single-Site and Inter-Site Effects in Heavy Fermion Compound CeRu2Si2 Studied by Constant Volume Dilution
K. Matsuhira; T. Sakakibara; H. Amitsuka; K. Tenya; K. Kamishima; T. Goto; G. Kido
J. Phys. Soc. Jpn., 巻：66, 開始ページ：2851, 1997年, ［査読有り］
Magnetovolume Effect of Co2B
T. Kanomata; Y. Ise; N. Kumagai; A. Haga; K. Kamishima; T. Goto; H. M. Kimura; H. Yoshida; T. Kaneko; A. Inoue
Journal of Alloys and Compounds, 巻：259, 開始ページ：L1-L4, 1997年, ［査読有り］
Magnetovolume effects of MnAs1-xSbx O. Nashima; T. Suzuki; H. Ido; K. Kamishima; T. Goto
Journal of Applied Physics,
巻：79,
号：8 PART 2A,
開始ページ：4647,
終了ページ：4649, 1996年04月
Thermal expansion, high-field magnetization, and susceptibility measurements have been made for MnAs0.7Sb0.3. The thermal expansion measurements show that the spontaneous magnetostriction is large and anisotropic below Tc. The spontaneous magnetostriction at 0 K is estimated to be 1.2×10-2 for a axis, -0.8×10-2 for c axis, and 1.6×10-2 for the volume. The spontaneous magnetization decreases sharply in the narrow temperature region below Tc=230 K. All the spontaneous magnetostrictions are found to be proportional to the square of spontaneous magnetization. The magnetization curves measured in a high field up to 40 T show the metamagnetic-like transitions at temperatures above Tc, and they are almost perfectly reproduced by an equation H=A1σ+A2σ3+A 3σ5, where H is the applied field and σ is the relative magnetization. © 1996 American Institute of Physics.
研究論文（学術雑誌）
DOI：https://doi.org/10.1063/1.361692Scopus：https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=0000042470&origin=inwardScopus Citedby：https://www.scopus.com/inward/citedby.uri?partnerID=HzOxMe3b&scp=0000042470&origin=inwardDOI ID：10.1063/1.361692,
ISSN：0021-8979,
SCOPUS ID：0000042470 Onset of ferromagnetism between the paramagnets UCoAl and URuAl
AV Andreev; Sechovsky, V; L Havela; J Sebek; MI Bartashevich; T Goto; K Kamishima; DA Andreev; VS Gaviko; RV Dremov; IK Kozlovskaya
CZECHOSLOVAK JOURNAL OF PHYSICS, 巻：46, 開始ページ：3385, 終了ページ：3386, 1996年, ［査読有り］
Effect of pressure and substitution of Co by Ru on magnetic properties of 5f-band metamagnet UCoAl has been studied. The onset of ferromagnetism between paramagnetic UCoAl and URuAl and strong pressure dependence of parameters of metamagnetic transition in UCoAl have been found.
CZECHOSLOVAK JNL OF PHYSICS, 英語, 研究論文（学術雑誌）
ISSN：0011-4626, Web of Science ID：WOS:A1996WH15200078
