Spin current effects in nanostructured films

该项目的重点将是图案化磁性结构中的自旋电流效应。我们建议研究磁激发的本征模式，这取决于结构的形状。在使用钛宝石激光脉冲作为频闪手电筒的全光泵浦和探测实验中，可以在多大程度上选择和操纵特殊模式？激励泵浦脉冲产生一种非平衡状态。弛豫过程中的散射过程导致了自旋系统与热化电子系统的耦合，并触发了相干和非相干磁化动力学。正如我们在微磁模拟中所看到的，相当小的退磁效应(~5-10%)激发了自旋系统的基模。这些模式强烈地受偶极场支配。这个项目的重点将是研究层状系统界面上这种非平衡情况下的自旋流。自旋流效应以两种方式进入自旋系综的复杂动力学：第一，自旋系统的相干进动在相邻的非磁性金属层中激发自旋流。这起到了依赖于自旋轨道散射的附加阻尼的作用。其次，注入到磁结构中的自旋电流通过守恒总角动量来启动自旋系统的进动。这两种影响都将在拟议的项目中进行研究。

Focus of the project will be spin current effects in patterned magnetic structures. We propose to investigate the eigen modes of magnetic excitations depending on the shape of the structures. In how far can special modes be selected and manipulated in an all optical pump and probe experiment using a Ti:sapphire laser pulse as a stroboscopic flashlight? The exciting pump pulse generates a nonequilibrium situation. Scattering processes during the relaxation process result in a coupling of the spin system with the thermalizing electron system as described in the three temperature model, and triggers coherent and non coherent magnetization dynamics. Rather small demagnetization effects of ~5-10% excite fundamental modes of the spin system as we have seen in micromagnetic simulations. The modes are strongly dominated by dipolar fields. Focus of this project will be the study of spin currents evolving from this nonequilibrium situation at the interfaces of layered systems. Spin current effects enter in the complex dynamics of the spin ensemble in two ways: Firstly, the coherent precession of a spin system excites a spin current in an adjacent nonmagnetic metallic layer. This acts as an additional damping dependent on the spin orbit scattering. Secondly, spin currents injected into a magnetic structure start a precession of the spin system by conserving the total angular momentum. Both effects will be studied within the proposed project.