Spin fluctuations and Magnetic Field Enhanced Superconductivity in two-dimensional localized system

我们获得了关于自旋准磁性效应在超导电性和局部化在两个尺寸薄Au-Ge电影中的竞争性影响的结果。（1） Tc-enhancement under parallel magnetic fields is confirmed from the observations of the decrease in resistances in resistive transitions for thin films of AuイイD20. 5イエD2 GeイD20. 5イエD2 in thickness region of about 2 nm。For those of Au D20.3 y D2 Ge D20.7 y D2 and Au D20.7 y D20.3 y D2， no Tc-enhancement is observed。（2）在抵抗性过渡的现场扫描和调制实验中，LkG以下的低场行为被发现与那些预期的稳定状态实验不同（1）在staggered field中的漩涡动力学。（3）典型的温度依赖性和非线性行为没有被忽视，因为外部场没有被完全排除。在T/Tco=0.7的最低温度下，抵抗出现在明显的应用Perpendicular字段H中，其温度依赖性与涡流流抵抗力对热刺激具有一致性。这意味着，漩涡玻璃过渡在两个维度系统中是空白的。（4） Resistive Transitions are Investigated Under exactly parallel fields by using a Hermholtz magnet to compensate the residual Perpendicular fields。Positive magnetoresistances due to localization are quadratically proportional to H// and the superconducting resistive transitions are scaled by T/Tc（H//）。Tc--从那些稳定的场实验中获得的抵抗力的场依赖性评估（1）。

We obtained the following results for the competitive effect of spin paramagnetic effect on superconductivity and localization in two-dimensional thin Au-Ge films.(1) Tc-enhancement under parallel magnetic fields is confirmed from the observations of the decrease in resistances in resistive transitions for thin films of AuィイD20.5ィエD2GeィイD20.5ィエD2 in thickness region of about 2nm. For those of AuィイD20.3ィエD2GeィイD20.7ィエD2 and AuィイD20.7ィエD2GeィイD20.3ィエD2, no Tc-enhancement is observed.(2) In field-sweep and -modulation experiments on resistive transition, the low field behavior below lkG is found to be different from those expected from the steady state experiments in (1) due to the vortex dynamics in staggered fields.(3) Typical temperature dependence and the nonlinear behavior are not obsereved because the external fields are not completely excluded. At the lowest temperature of T/Tco=0.7, resistance appears linearly with increasing applied perpendicular field H and its temperature dependence is consistent with the vortex flow resistivity due to thermal excitation. This implies that the vortex-glass transition is absent in two dimensional system.(4) Resistive transitions are investigated under exactly parallel fields by using a Hermholtz magnet to compensate the residual perpendicular fields. Positive magnetoresistances due to localization are quadratically proportional to H// and the superconducting resistive transitions are scaled by T/Tc(H//). The Tc-enhancement evaluated from the field dependence of resistance agree with those obtained in steady field experiments in (1).