Current-induced magnetization instabilities in thin magnetic films: self-consistent Langevin dynamics simulations

本项目的主要目标是定性地提高我们对电流和铁磁膜磁化之间的相互作用的理论认识，这是由于自旋转移现象。根据最近的理论预测，已经有一个非极化电流（即，一个没有净自旋极化的电流）流过铁磁层可以诱导其磁化结构的不稳定性，导致磁化激励和开关的出现。我们打算将伴随自旋扩散的磁化依赖自旋积累（这被认为是导致这些不稳定性的机制）纳入自旋转移现象的全尺寸微磁模拟中。由于考虑到这一定性新效应，我们期望对具有实验相关尺寸的结构中的自旋转移诱导磁化动力学有更好的理解，其中应考虑到复杂介观畴图案的形成。从潜在的应用角度来看，本项目的结果应该是非常有趣的，有助于建立自旋极化和非极化电流诱导纳米元件磁化的开关和稳态进动的最佳条件。

The main goal of this project a qualitative improvement of our theoretical understanding of the interaction between an electric current and a magnetization of a ferromagnetic film due to the spin-transfer phenomena. According to recent theoretical predictions, already a nonpolarized current (i.e., a current without a net spin polarization) flowing through a ferromagnetic layer can induce instabilities of its magnetization configuration, causing the appearance of magnetization excitations and switching. We intend to include the magnetization-dependent spin accumulation accompanied by a spin-diffusion (which is supposed to be the mechanism responsible for these instabilities) into the full-scale micromagnetic simulations of the spin-transfer phenomena. As a result of taking into account this qualitatively new effect we expect a decisively better understanding of the spin-transfer induced magnetization dynamics in structures with experimentally relevant sizes, where the formation of complicated mesoscopic domain patterns should be taken into account. From the point of view of potential applications results of this project should be of a great interest, helping to establish optimal conditions for switching and steady-state precession of a nanoelement magnetization induced by a spin-polarized and unpolarized currents.