Ab initio description of magnetization dynamics in tunnel junctions: Influence of bias voltage and material parameters

这个提议的目标是研究磁性隧道结中的动态磁性过程，这对未来的自旋电子学应用（如磁性存储器）非常重要。对于成功的高密度存储器器件，期望一方面具有有效的自旋转移扭矩，另一方面具有低的磁阻尼。该项目的目的是了解阻尼和自旋转移扭矩的基本机制，特别是它们对偏置，材料和几何形状的依赖。电子-声子和电子-磁振子散射对偏置依赖性的影响是该建议的一个关键方面。另一个关键方面是对各种材料进行这些计算，包括今天使用的合金和非晶材料以及半金属系统，这些系统因其高磁阻潜力而受到关注。动力学对这些材料性能的影响不如单晶过渡金属铁磁体那么好理解。所有这些研究都将使用从头算方法进行。其中一些需要在方法上加以发展。

The goal of this proposal is to investigate the dynamic magnetic processes in magnetic tunnel junctions that are important for future spintronics applications like magnetic memories. For successful high density memory devices it is desirable to have an effective spin-transfer torque on one hand and a low magnetic damping on the other hand. The purpose of the project is to understand the fundamental mechanisms for damping and for spin-transfer torque, particularly their dependence on bias, materials, and geometry. The influence of electron-phonon and electron-magnon scattering on the bias dependence is a key aspect of the proposal. Another key aspect is performing these calculations for a variety of materials, including alloys and amorphous materials, which are used today and half-metallic systems, which are of interest for their potential for high magnetoresistance. The effect of the dynamics on the performance of these materials is less well understood than it is for single crystal transition metal ferromagnets. All of these investigations will be done using an ab initio approach. Some of them require methodological developments.