巻号一覧
59 巻, 3 号
March
選択された号の論文の10件中1～10を表示しています
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研究
研究
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Mei Fusa, Natsuki Sumida, Kazuhiro Hasezaki原稿種別: Paper
2012 年 59 巻 3 号 p. 121-125
発行日: 2012/03/15
公開日: 2012/06/15
ジャーナル オープンアクセスBi2Te2.85Se0.15 was prepared, without doping materials, by two different processes: mechanical alloying-hot pressing (MA-HP) and melt quenching (MQ). Doped Bi2Te2.85Se0.15 is a well-known n-type Bi2Te3-based material. MA was carried out for 30 h. The MA-HP samples were obtained by hot pressing at 673 K under a mechanical pressure of 147 MPa in an argon atmosphere. The MQ samples were prepared by direct melting of the constituent elements at 973 K in an evacuated quartz ampoule followed by quenching into water.
These samples were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), optical microscopy (OM), and thermoelectric property measurements. The samples were identified as single-phase materials related to Bi2(Te, Se)3. The MA-HP sample showed n-type conduction, but the MQ sample showed p-type conduction. The carrier densities of the MA-HP and MQ samples at room temperature were, respectively, 1.80×1025 m-3 of n-type carriers and 2.90×1025 m-3 of p-type carriers. The maximum values of the figure of merit ZT for the MA-HP and the MQ samples were 0.853 at 313 K for n-type and 0.064 at 353 K for p-type, respectively.抄録全体を表示PDF形式でダウンロード (1470K) -
世利 修美, 蓑島 創2012 年 59 巻 3 号 p. 126-130
発行日: 2012/03/15
公開日: 2012/06/15
ジャーナル オープンアクセスAttempts have been made to obtain CaTiO3 powder by mixture of corrosion products of calcium in H2O2 solution at 373 K and titanium in H2O2+NH3 solution at room temperature for a few hours. The white calcium hydroxide and yellow peroxotitanium hydroxide aboves were mixtured and sintered at 673-1273 K for 7.2 ks. CaTiO3 particles in micron sizes have been identified by XRD analysis and SEM observations. As an example of the corrosion synthesis method, the synthesis of CaTiO3 was electrochemically considered as the mixture of corrosion products of calcium and titanium in corrosive environments.抄録全体を表示PDF形式でダウンロード (888K) -
佐々木 遼, 神島 謙二, 柿崎 浩一, 石丸 雄大, 酒井 政道, 平塚 信之2012 年 59 巻 3 号 p. 131-136
発行日: 2012/03/15
公開日: 2012/06/15
ジャーナル オープンアクセス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.抄録全体を表示PDF形式でダウンロード (656K)
特集：グリーン／ライフ・イノベーションに向けた磁性材料・デバイスの新展開
総報
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松下 伸広2012 年 59 巻 3 号 p. 138-
発行日: 2012/03/15
公開日: 2012/06/15
ジャーナル オープンアクセスPDF形式でダウンロード (138K)
研究
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田中 真, 緒方 祐史, 中川 茂樹2012 年 59 巻 3 号 p. 139-144
発行日: 2012/03/15
公開日: 2012/06/15
ジャーナル オープンアクセスMgO underlayer with (001) preferential orientation formed on a thin Fe seed layer is used to attain L10 ordered phase 2 nm-thick FePt films with (001) orientation. The Fe [1 nm]/Pt [1 nm] bilayer can be grown epitaxially on the MgO underlayer with (001) aligned texture and the bilayer transformed into (001)-textured L10-FePt films after annealing at 600°C. 2 nm-thick FePt films with (001) preferential orientations can be prepared on a thick MgO underlayer with (001) orientation. Since such a thin thickness of Fe and Pt layers enhances an inter-diffusion process between the layers, the crystallization and ordering temperature of FePt decreases from 550°C to 500°C. Furthermore, FePt was successfully attained at lower annealing temperature (450°C) by adding Au into FePt.抄録全体を表示PDF形式でダウンロード (1013K) -
間宮 啓介, 久保田 雄紀, 中川 茂樹2012 年 59 巻 3 号 p. 145-148
発行日: 2012/03/15
公開日: 2012/06/15
ジャーナル オープンアクセスCo ferrite films have been grown by a reactive ion beam sputtering under the Kr and O2 mixture atmosphere. Most of the film contains (100) texture of Co spinel ferrite when the partial pressure ratio of O2 is 8.6 %. Completely (100) orientated CoFe2O4 films can be grown on Fe (10 nm)/MgO (10 nm) underlayer with (100) orientation. 5 nm-thick (100) CoFe2O4 film is observed prepared at substrate temperature of 200°C. The (100) texture and the expansion of the lattice are the origin of the in-plane magnetic anisotropy. The internal stress expanding to perpendicular to plane is released at high substrate temperature. Thus, lattice expansion getting smaller at 200°C than 100°C. (100) well orientated CoFe2O4 films can be grown not only Fe/MgO dual underlayer, but on Fe (10 nm) single underlayer.抄録全体を表示PDF形式でダウンロード (454K) -
小原 学, 倉橋 峻, 清田 昌宏, 中村 龍哉, 山田 義博2012 年 59 巻 3 号 p. 149-155
発行日: 2012/03/15
公開日: 2012/06/15
ジャーナル オープンアクセスThe MnxFe3-xO4 powders were prepared by a coprecipitation method or a solid state reaction. The effect of specific surface area on electrochemical properties and the relationship between the electrochemical properties and manganese substitution values were examined by BET method and chrono-potentiometry. The results indicate that capacitance per unit weight of MnFe2O4 is proportional to specific surface area. Furthermore, capacitance per specific surface of MnxFe3-xO4 is constant to about 65 μF/cm2 despite the increase of the manganese substitution values (x≥1.0).抄録全体を表示PDF形式でダウンロード (565K) -
高田 幸生, 金子 裕治2012 年 59 巻 3 号 p. 156-160
発行日: 2012/03/15
公開日: 2012/06/15
ジャーナル オープンアクセスDy-diffusion process is one of effective methods to improve the coercivity of NdFeB sintered magnets with a small amount of Dy usage. In order to achieve further improvements of coercivity, we investigated microstructural factors such as grain size and impurity of NdFeB sintered magnets after Dy-diffusion treatment. One of our results indicates that oxygen, as existing impurity in NdFeB magnets, reacts with the diffused Dy to generate Nd-Dy oxide which mainly remains at triple junctions of NdFeB grains. As the oxidization of Dy could not work to improve coercivity, reducing the oxygen content is effective to enhance the Dy-diffusion effect. On the other hand, we tried another technique to protect from oxidization of Dy, in which rare-earth fluorides were doped into NdFeB sintered body. We found that the doped fluoride could trap oxygen such as the formation of NdOF. After that, Dy could smoothly come into grain boundaries because of non-reaction with oxygen. Then, coercivity of magnets showed to be remarkable improvement.抄録全体を表示PDF形式でダウンロード (1292K)
本会記事
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2012 年 59 巻 3 号 p. Pref3_1-
発行日: 2012/03/15
公開日: 2012/06/15
ジャーナル オープンアクセスPDF形式でダウンロード (98K) -
2012 年 59 巻 3 号 p. MtgPr3_2-MtgPr3_24
発行日: 2012/03/15
公開日: 2012/06/15
ジャーナル オープンアクセスPDF形式でダウンロード (751K)
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