研究者詳細 - 生田　博志

論文 - 生田　博志

分割表示 274 件中 161 - 180 件目／全件表示 >>

Growth and properties of thermoelectric oxide whiskers

R. Funahashi, H. Ikuta, T. Takeuchi, U. Mizutani, I. Matsubara, M. Shikano

Oxide Thermoelectrics 頁： 83-99 2002年

Three-dimensional Fermi-liquid ground state in the quasi-one-dimensional cuprate PrBa_2_Cu_4_O_8_ 査読有り

N. E. Hussey, M. N. McBrien, L. Balicas, J. S. Brooks, S. Horii, H. Ikuta

Physical Review Letter 89 巻頁： 086601 2002年

Free flux flow resistivity in strongly overdoped high-T_c_ cuprate; purely viscous motion of the vortices in semiclassical d-wave superconductor 査読有り

Y. Matsuda, A. Shibata, K. Izawa, H. Ikuta, M. Hasegawa, Y. Kato

Physical Review B 66 巻頁： 014527 2002年

Zn-substitution effect on the optical properties of PrBa_2_Cu_4_O_8_ 査読有り

K. Takenaka, A. Osuka, S. Sugai, K. Nakada, S. Horii, H. Ikuta, U. Mizutani

Physica C 383 巻頁： 227-231 2002年

Transport Properties and Magnetoresistance of (RE,Sr)_2_NiO_4_ (RE=Pr, Nd, Sm and Eu) 査読有り

K. Sugiyama, H. Nozaki, T. Takeuchi, H. Ikuta

Journal of Physics and Chemistry of Solids 63 巻頁： 979-982 2002年

Oxygen diffusivity in melt-processed SmBCO and YBCO bulk-superconductors 査読有り

T. Yamada, H. Ikuta, M. Yoshikawa, Y. Yanagi, Y. Itoh, T. Oka, U. Mizutani

Physica C 378-381 巻頁： 713-717 2002年

Extracting the utmost from the high performance of Sm-Ba-Cu-O bulk superconductors by pulse field magnetization 査読有り

H. Ikuta, H. Ishihara, Y. Yanagi, Y. Itoh, U. Mizutani

Superconductor Science and Technology 15 巻頁： 606-612 2002年

Metallic c-axis transport across insulating planes in PrBa_2_Cu_4_O_8_ 査読有り

M. N. McBrien, N. E. Hussey, P. J. Meeson, S. Horii, H. Ikuta

Journal of Physical Society of Japan 71 巻頁： 701-704 2002年

Synthesis and magnetization of high-T_c_ bulk superconductors and their application as superconducting permanent magnets 査読有り

U. Mizutani, H. Ikuta, T. Oka, Y. Itoh, Y. Yanagi, M. Yoshikawa

International J. Appl. Electromagnetics and Mechanics 14 巻頁： 57-63 2002年

Co系長尺酸化物ウィスカーの成長と熱電特性

舟橋良次、生田博志、鹿野昌弘、松原一郎、水谷宇一郎

紛体および粉末冶金 49 巻頁： 393-399 2002年

超電導バルク磁石を使った3.15 T強磁場発生装置の開発査読有り

岡徹雄、横山和哉、伊藤佳孝、柳陽介、吉川雅章、生田博志、水谷宇一郎、岡田秀彦、能登宏七

低温工学 37 巻頁： 689-696 2002年

バルク超電導体のパルス着磁技術

岡徹雄、伊藤佳孝、柳陽介、吉川雅章、生田博志、水谷宇一郎

日本AEM学会誌 10 巻頁： 136-142 2002年

Topology of the Fermi surface and Band Structure near the Fermi level in the Pb-doped Bi_2_Sr_2_CuO_6+δ_ superconductor 査読有り

T. Takeuchi, T. Yokoya, S. Shin, K. Jinno, M. Matsuura, T. Kondo, H. Ikuta, and U. Mizutani

Journal of Electron Spectroscopy and Related Phenomena 114-116 巻頁： 629 2001年

First-order vortex phase transition in Bi_2_Sr_2_CaCu_2_O_y_ single crystals with different carrier concentrations studied by resistivity measurements 査読有り

S. Watauchi, H. Ikuta, H. Kobayashi, J. Shimoyama, and K. Kishio

Physical Review B 64 巻頁： 064520 2001年

記述言語：英語掲載種別：研究論文（学術雑誌）

The first-order vortex phase transition (FOT) in Bi_2_Sr_2_CaCu_2_O_y_ single crystals with different carrier concentrations was investigated by measuring the in-plane resistivity (r_ab_) under magnetic field applied parallel to the crystallographic c-axis direction. With decreasing the temperature, r_ab_ dropped sharply at the FOT temperature when the applied field was smaller than the second-peak-field (H_pk_) that was determined by measuring the magnetic hysteresis curves at 25-30 K, while no such an abrupt change was observed when the applied field was larger than H_pk_. The temperature range where the FOT was observed was approximately between 0.6 to 0.95 in the scale of the reduced temperature (t=T/T_c_) for all crystals. The first-order transition field (H_t_) as a function of t shifted to higher fields as the carrier concentration of the crystal increased, which can be well scaled by the electromagnetic anisotropy factor (g). Irrespective of the carrier doping level, the temperature dependence of H_t_ is experimentally expressed better by H_t_=a(t^-1^-t), rather than the functional form proposed by the conventional decoupling theory of vortex lattice (H_t_=a(t^-1^-1)). This experimental formula can be accounted for by the decoupling theory if the temperature dependence of the magnetic penetration depth is assumed to scale as l^-2^=a(1-t^2^).

Non-cuprate thin films as candidates of seed layer for liquid phase epitaxy process 査読有り

T. Miura, Y. Yamada, T. Suga, D. Huang, S. B. Kim, T. Maeda, I. Hirabayashi, H. Ikuta, and U. Mizutani

Physica C 357-360 巻頁： 983 2001年

YBCO Thin Films on Multilayers Prepared by All-Chemical Solution Deposition Processing 査読有り

H. Hiei, K. Yamagiwa, Y. Takahashi, S. B. Kim, Y. Yamada, J. Shibata, T. Hirayama, H. Ikuta, I. Hirabayashi, and U. Mizutani

Physica C 357-360 巻頁： 942 2001年

記述言語：英語掲載種別：研究論文（学術雑誌）

The chemical solution deposition (CSD) technique has been applied to prepare both YBa_2_Cu_3_O_7-d_ (YBCO) and buffer layers on a YSZ substrate. Y_2_O_3_ and CeO_2_ were employed as the buffer layers, and it was confirmed that they grew epitaxially by the CSD method. Cross-sectional TEM observations revealed that Y_2_O_3_ grew up to the top of the film. Furthermore, the YBCO film on the Y_2_O_3_ or CeO_2_/Y_2_O_3_ layers were c-axis aligned and showed a good in-plane alignment. The transition temperature and the critical current density of the YBCO/Y_2_O_3_/YSZ multilayer were 89 K and 4.0x10^4^ A/cm^2^ at 77 K, 0T, respectively.

Melt-Processing and the Performance as a Superconducting Permanent Magnet of RE-Ba-Cu-O/Ag (RE=Sm, Nd) 査読有り

H. Ikuta, Y. Yanagi, M. Yoshikawa, Y. Itoh, T. Oka, and U. Mizutani

Physica C 357-360 巻頁： 837 2001年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

The amount of magnetic flux that a melt-processed bulk-superconductor can trap has drastically increased recently by the successful synthesis of single domain RE-Ba-Cu-O (RE=Sm, Nd) samples with the addition of Ag. As a result of this progress in processing, it became increasingly important to develop an efficient and practical magnetization technique to extract the potential of the material in applications that use melt-grown superconductors as quasi-permanent magnets. We review our recent works on the melt-growth technique as well as the pulse field magnetization studies. Using these techniques, we have constructed a magnetic field generator, the performance of which is evaluated in this study.

Improvement of the Microstructure of Melt-Processed Sm-Based Superconductors 査読有り

K. Tazoe, H. Ikuta, M. Yoshikawa, Y. Yanagi, Y. Itoh, T. Oka, and U. Mizutani

Physica C 357-360 巻頁： 807 2001年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

We report on the effect of the atmosphere during the decomposition of the precursors of Sm-Ba-Cu-O bulk superconductors. It was found that the formation of voids was greatly suppressed by two methods, melting in an oxygen gas atmosphere or in vacuum. For both meth-ods, the atmosphere during crystallization was switched to an Ar-gas flowing one. The samples prepared by these methods exhibited high superconducting transition temperatures with sharp transition widths. However, the zero-field critical current density was lower than that of the reference sample, which was prepared by decomposing the precursor in an Ar-gas flowing atmosphere.

Pulsed Field Magnetization of Melt-Processed Sm-Ba-Cu-O 査読有り

H. Ishihara, H. Ikuta, Y. Itoh, Y. Yanagi, M. Yoshikawa, T. Oka, and U. Mizutani

Physica C 357-360 巻頁： 763 2001年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

We studied the dynamical motion of flux lines in a melt-processed Sm-Ba-Cu-O bulk-superconductor driven by a magnetic pulse using seven small Hall sensors. The time dependence of the magnetic flux density was measured on a crystalline facet line and on an inter-facet region. It was observed that flux lines move faster along the inter-facet region, and a larger amount of magnetic flux is trapped in the facet regions after the application of a magnetic pulse. A comparatively larger pinning effect in the facet region is considered to be responsible for these observations.

Effect of Zn Substitution on the One-Dimensional Metallic Behavior of PrBa_2_Cu_4_O_8_ 査読有り

K. Nakada, H. Ikuta, S. Horii, H. Nozaki, I. Hirabayashi, and U. Mizutani

Physica C 357-360 巻頁： 186 2001年

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（学術雑誌）

We have grown PrBa_2_(Cu_1-x_Zn_x_)_4_O_8_ single crystals with nominal compositions of x=0, 0.05, 0.10, and 0.15, and measured the resistivity along a- and b-axis directions. For the Zn-free sample, the conduction along the b-axis direction was highly metallic, which persisted up to the x=0.15 sample although the doping of Zn increased the resistivity. On the other hand, the a-axis resistivity of the Zn-free crystal exhibited a peak around 130 K, which is attributable to a switching of the dominant conduction path from the Cu-O chain site at low temperature to the CuO_2_ plane at high temperature. With Zn doping, the peak moves to lower temperature and the resistivity extrapolated to T=0 increases, indicating that Zn doping suppresses the coherent conduction across Cu-O chains.

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