Correlation between superconductivity and ferromagnetism for nano-sized particle-dispersion-controlled thin films

纳米粒子色散控制薄膜的超导性与铁磁性之间的相关性

• 批准号: 10650646
• 负责人: OBI Yoshihisa
• 金额: $ 2.24万
• 依托单位: TOHOKU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10650646/
• 关键词: superconductivity; ferromagnetism; thin film; critical temperature; upper critical field; proximity effect; 多層膜; キュリー温度

The purpose of this study is to investigate the influence of magnetic particles dispersed in superconducting matrix with nano-scale or ferromagnetic thin films touched by superconducting thin films to the superconductivity, that is, to investigate the correlation between superconductivity and ferromagnetism. To do so, we have added the consideration for the three systems made by sputter deposition as (1) superconductor/ferromagnet multilayer, (2) superconducting thin film dispersed by ferromagnetic particles in it, and (3) superconductor/non-magnetic material (including another type superconductor) multilayers. The main results are as follows: (i) We have found the 2-step oscillation phenomenon for Nb/Co and V/Co multilayers. This phenomenon is interpreted by the so-called π-phase theory. (ii) The dispersion system (Nb-matrix with Fe particles dispersed in matrix) shows the Tc degradation accompanied by the increase of Fe particle as obeying the law of the Abrikosov-Gorkov theory. (iii) The behavior of upper critical field and transition temperature observed in the superconductor/superconductor multilayers obeys the proximity-effect-theory.

本研究的目的是研究纳米尺度的超导基体中分散的磁性粒子或与超导薄膜接触的铁磁薄膜对超导性的影响，即研究超导性与铁磁性之间的相关性。为此，我们增加了对溅射沉积制备的三种系统的考虑：（1）超导体/铁磁体多层膜，（2）其中分散有铁磁颗粒的超导薄膜，和（3）超导体/非磁性材料（包括另一种类型的超导体）多层膜。主要结果如下：（i）发现了Nb/Co和V/Co多层膜的两步振荡现象。这种现象可以用所谓的π相理论来解释。(ii)分散体系（Nb-基体，Fe颗粒分散在基体中）的Tc随Fe颗粒的增加而降低，符合Abrikosov-Gorkov理论。(iii)在超导体/超导体多层膜中观察到的上临界场和转变温度的行为服从邻近效应理论。

项目成果

Y. Obi, M. Ikebe, H. Fujishiro and H. Fujimori: "Flux Pinning Characteristics in NbTi/Nb Superconductor/Superconductor Multilayers"Physica B. in press. (2000)

Y. Obi、M. Ikebe、H. Fujishiro 和 H. Fujimori：“NbTi/Nb 超导体/超导体多层中的磁通钉扎特性”Physica B. 已出版。

Y. Obi, M. Ikebe, H. Wakou and H. Fujimori: "Superconducting Transition Temperature and Dimensional Crossover in Nb/Co and V/Co Multilayers"Journal of Physical Society Japan. Vol.68, No.8. 2750-2754 (1999)

Y. Obi、M. Ikebe、H. Wakou 和 H. Fujimori：“Nb/Co 和 V/Co 多层中的超导转变温度和维度交叉”日本物理学会杂志。

小尾俶久: "Oscillation phenomenon of transition temperatures in Nb/Co and V/Co superconductor/ferromagnet multiayers" Physica C. (1999)

Takehisa Obi：“Nb/Co 和 V/Co 超导体/铁磁体多层中转变温度的振荡现象”Physica C. (1999)

小尾叙久: "Oscillation phenomenon of transition temperatures in Nb/Co and V/Co superconductor / ferromagnet multilayers"Physica C. 317-318. 149-153 (1999)

Yukihisa Obi：“Nb/Co 和 V/Co 超导体/铁磁体多层中转变温度的振荡现象”Physica C. 317-318 (1999)。

小尾叙久: "Flux pinning characteristics in NbTi/Nb superconductor/superconductor multilayers"Physica B. (2000)

Yukihisa Obi：“NbTi/Nb 超导体/超导体多层中的磁通钉扎特性”Physica B. (2000)