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

这个项目的主要目的是从本质上改进我们对自旋转移现象引起的铁磁性薄膜的电流和磁化之间的相互作用的理论理解。根据最近的理论预测，流过铁磁层的非极化电流(即没有净自旋极化的电流)已经可以引起其磁化构型的不稳定性，导致磁化激发和开关的出现。我们打算将伴随着自旋扩散的磁化相关的自旋积累(这被认为是导致这些不稳定性的机制)包括在自旋转移现象的全尺寸微磁模拟中。由于考虑了这一全新的效应，我们期待着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决定性的更好的理解，其中应该考虑复杂的介观磁区图案的形成。从潜在应用的角度来看，这个项目的结果应该是非常有意义的，有助于建立由自旋极化和非极化电流诱导的纳米元素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.