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Study of spin-switching by meansot superconductor-ferromagnet junction

超导-铁磁体结自旋开关研究

基本信息

批准号：
13650710
负责人：
OBI Yoshihisa
金额：
$ 2.3万
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：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650710/
关键词：
superconductor ferromagnet thin film multilayer critical temperature proximty effect 超電導折接効果超伝道

项目摘要

Ferromagnet(F)/Superconductor(S)/Ferromagnet(F) junction is theoretically expected to have different superconducting critical temperature(Tc) between parallel(P) and antiparallel(AP) coupling of the magnetic spins of both the ferromagnetic layers, that is huge change in electrical resistivity will be possible under the change in small magnetic field. This new junction is prospected to the practical use for the novel switching sensor having high S/N ratio under low driving magnetic field. In order to investigate the possibility above mentioned Tc-difference, we have done the Tc measurement in addition to the basic superconducting properties, which is necessary for the exploitation of new material, for the several multilayer systems, such as (1) S/N(normal metal), (2) S/F and (3) AF(antiferromagnet)/F/S/F. The results of the measurement for the systems (1) and (2) make clear the basic superconducting properties such as Tc and Hc2. Especially we have found the different oscillation behavior between S/F tri- and penta-layers reflecting the ο- and π- phases of superconducting pair funcfion. The result of the measurement for system (3) shows that, by means of selecting available size of F-layer's thickness, the magnetization measurement reveals the parallel and antiparallel coupling of both F-layers depending on the applied magnetic field. The difference in Tc accompanied by the parallel and antiparallel magnetic coupling, however, is very small even selecting optimum size of Slayer thickness.

铁磁体（F）/超导体（S）/铁磁体（F）结理论上预期在两个铁磁层的磁自旋的平行（P）和反平行（AP）耦合之间具有不同的超导临界温度（Tc），即在小磁场变化下电阻率将可能发生巨大变化。该结有望在低驱动磁场下实现高信噪比的新型开关传感器。为了研究上述Tc差异的可能性，除了开发新材料所需的基本超导性质之外，我们还对几种多层体系进行了Tc测量，例如（1）S/N（正常金属），（2）S/F和（3）AF（反铁磁）/F/S/F。系统（1）和（2）的测量结果清楚地表明了基本的超导性质，如Tc和Hc 2。特别是发现了S/F三层和五层之间不同的振荡行为，反映了超导对函数的o相和π相。对系统（3）的测量结果表明，通过选择合适的F层厚度，磁化强度测量揭示了两个F层之间的平行和反平行耦合随外加磁场的变化。然而，即使选择最佳的Slayer厚度尺寸，平行和反平行磁耦合所伴随的Tc的差异也是非常小的。