Spin-Polarized Tunneling Study of Spin Effects in the Superconducting State

9424467泰德罗自旋极化电子隧穿的发现使得在外加磁场存在的情况下对超导状态进行详细探测成为可能，这在以前是不可能的。特别是，作为自旋过滤器的隧道势垒的发展极大地增加了这项技术的多功能性。在这项工作中，自旋极化隧穿技术将被用来研究三种外加影响区中薄膜超导体的态密度。在第一种情况下，超导体将受到准粒子通过自旋过滤隧道势垒的注入，以便观察可能的自旋相关的非平衡效应。第二部分研究了稀土杂质引起的自旋-轨道散射和磁交换相互作用引起的自旋态混合。最后，交换邻近效应将与隧道光谱一起用于验证Fulde-Ferrell-Larkin-Ovchinnikov态的存在。提出了利用自旋极化电子隧穿实验技术研究薄膜超导材料中传导电子能量(所谓的“态密度”)分布的实验。在这种技术中，具有一个自旋(磁矩)取向的电子优先通过绝缘磁障进入超导体；产生的电流提供了超导体中电子能量的映射。在外加磁场的影响下和在超导薄膜中掺杂磁性杂质原子的情况下，研究这些效应将获得进一步的信息。***

9424467 Tedrow The discovery of spin-polarized electron tunneling has made possible detailed probing of the superconducting state in the presence of applied magnetic fields to an extent not previously possible. In particular, the development of tunnel barriers that act as spin filters has greatly increased the versatility of this technique. In this work, the spin-polarized tunneling technique will be applied to the investigation of the density of states of thin-film superconductors in three regimes of external influence. In the first regime, the superconductor will be subjected to injection of quasiparticles through a spin-filter tunnel barrier to allow observatio of possible spin-dependent nonequilibrium effects. In the second, spin state mixing caused by spin-orbit scattering and magnetic exchange interactions arising in rare-earth impurities will be studied. Finally, the exchange proximity effect will be used along with the tunneling spectroscopy to attempt to verify the existence of the Fulde-Ferrell-Larkin-Ovchinnikov state. %%% Experiments are proposed to study the distribution of conduction electron energies (the so-called "density of states") in thin-film superconducting materials by means of the experimental technique of spin-polarized electron tunneling. In this technique, electrons of one spin (magnetic moment) orientation "tunnel" preferentially through an insulating magnetic barrier into the superconductor; the resulting current provides a map of the electron energies in the superconductor. Further information will be gained by studying these effects under the influence of external magnetic fields and in the presence of magnetic impurity atoms doped into the superconducting films. ***