Theory of giant thermal magnetogalvanic effects in magnetic tunnel junctions

以氧化镁为势垒的磁性隧道结在自旋-热效应应用中具有广阔的应用前景。当使用CoFe磁性层时，MgO势垒起到对称滤光器的作用，导致高自旋极化电流。这样的连接显示了两个自旋通道的输运性质的巨大差异。因此，人们还可以期待巨大的自旋-热量效应，如磁热电势。CoFe合金的一个缺点是自旋扩散长度较短，这使得该系统不太适合自旋-塞贝克效应。这种不足可以通过使用半金属导线来克服。特别是，我们将重点介绍Co2FeAl Heusler化合物。在这个项目中，我们对自旋-塞贝克(或自旋相关的塞贝克)效应和磁热电势进行了从头计算。此外，我们将开发一种方法来解释电子-磁振子耦合，以计算输运性质和自旋转移扭矩作为温度的函数。

Magnetic tunnel junctions with MgO as a barrier are promising candidates for spin-caloric applications. The MgO barrier acts as a symmetry filter which leads to a high spin polarized current when CoFe magnetic layers are used. Such junctions show a huge difference in the transport properties of both spin channels. Consequently, one can expect also huge spin-caloric effects like magnetothermoelectric power. A drawback of CoFe alloys is the short spin diffusion length which makes this system less suitable for the spin-Seebeck effect. This insufficiency can be overcome by using halfmetallic leads. In particular, we will focus on the Co2FeAl Heusler compound. In this project we perform ab intio calculations of the spin-Seebeck (or spin-dependent Seebeck) effect and the magento-thermoelectric power. Further we will develop a method to account for electron-magnon coupling to calculate transport properties and the spin-transfer torque as a function of temperature.