arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1206.4470cond-mat.mes-hall
收藏

自旋阀、畴壁和其它织构磁体中横向自旋流的统一漂移扩散理论

A unified drift-diffusion theory for transverse spin currents in spin valves, domain walls and other textured magnets

Cyril Petitjean, David Luc, Xavier Waintal

摘要:

横向于铁磁体磁化方向的自旋只在很短的距离内存在。我们开发了一个漂移扩散的方法,捕获系统中的横向自旋效应的主要特征与任意自旋纹理(涡,域壁)和推广的Valet-Fert理论。除了标准的特征长度(多数和多数电子的平均自由程,自旋扩散长度),该理论引入了两个长度尺度,横向自旋相干长度和(拉莫尔)自旋进动长度。我们展示了如何从从头计算中提取这些长度或用巨磁阻实验测量。在长(绝热)畴壁,我们提供了一个解析公式,表示所谓的“非绝热”(或类场)的扭矩在这些长度尺度。然而,这种“非绝热”扭矩不再是一个简单的材料参数,而是取决于实际的自旋织构:在薄(<10 nm)的畴壁中,我们观察到与绝热极限非常显著的偏差。

英文摘要:

Spins transverse to the magnetization of a ferromagnet only survives over a short distance. We develop a drift-diffusion approach that captures the main features of transverse spin effects in systems with arbitrary spin textures (vortices, domain walls) and generalizes the Valet-Fert theory. In addition to the standard characteristic lengths (mean free path for majority and manority electrons, spin diffusion length), the theory introduces two lengths scales, the transverse spin coherence length and the (Larmor) spin precession length. We show how those lengths can be extracted from ab-initio calculations or measured with giant magneto-resistance experiments. In long (adiabatic) domain walls, we provide an analytic formula that expresses the so called "non-adiabatic" (or field like) torque in term of those lengths scales. However, this "non adiabatic" torque is no longer a simple material parameter and depends on the actual spin texture: in thin (< 10nm) domain walls, we observe very significant deviations from the adiabatic limit.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑