Study of the Superconducting Proximity Effect of Cu-Nb systems with Magnetic Impurities and Application for the New Superconducting Wire.

1. 研究了含Fe、Co、Ni、Mn等磁性杂质的Cu包覆Nb丝试样的迈斯纳效应。通过交流方法在10mK-10K的温度范围内进行测量。在含这些磁性杂质的铜中观察到由于近藤效应而产生的巨大依赖性。在温度范围内，迈斯纳区P与T^<-1/2>成正比。结果表明，在温度范围内，s-d交换作用引起自旋翻转散射的概率几乎没有变化。最近，Narikiyo和Fukuyama计算了P的温度依赖性，他们发现P随着温度的降低而增加，低于近藤温度T_K。我们的结果与计算不一致。含磁性杂质铜包导线的应用前景有待进一步研究，以开发超导导线的新材料。对Cu和Nb薄层进行了核磁共振研究。通过对Cu核自旋晶格弛豫时间T_1的测量，发现超导能量气体是由邻近效应诱导产生的。超导电子和正常电子在铜中同时存在，这与我们的预期一致。

1. The Meissner effect of Cu clad Nb wire samples with magnetic impurities such as Fe, Co, Ni and Mn has been studied. The measurements was done over the temperature range of 10mK-10K by means of the a.c. method. The large depairing effect due to the Kondo's effect was observed in Cu with these magnetic impurities. The Meissner region, P, was found to be proportional to T^<-1/2> over the temperature range. The result implies that the probability of the spin-flip scattering by the s-d exchange interaction is almost unchanged over the temperature range. Recently, Narikiyo and Fukuyama have calculated the temperature dependence of P. They indicate that P increases below Kondo's temperature T_K as decreasing temperature. Our results are not consistent with the calculation.The Cu clad wire with magnetic impurities is under further investigation for application, in order to develop new materials for the superconducting wires.2. The NMR study was carried out of the Cu and Nb thin multi-layers. From the measurements of the nuclear spin lattice relaxation time, T_1, of Cu nuclei, the superconducting energy gas was found to be induced by the proximity effect. Both superconducting and normal electrons were found to coexist in Cu as our expectation.