Theory of giant thermal magnetogalvanic effects in magnetic tunnel junctions

以氧化镁为势垒的磁隧道结是自旋热应用的有希望的候选者。当使用CoFe磁层时，MgO势垒作为对称滤光器导致高自旋极化电流。这样的结显示出两种自旋通道在输运性质上的巨大差异。因此，人们也可以期待巨大的自旋热效应，如磁热电效应。CoFe合金的缺点是自旋扩散长度短，这使得该体系不太适合自旋-塞贝克效应。这种不足可以通过使用半金属引线来克服。我们将特别关注Co2FeAl Heusler化合物。在这个项目中，我们进行了自旋-塞贝克（或自旋依赖的塞贝克）效应和磁热电功率的从头计算。此外，我们将开发一种方法来考虑电子-磁振子耦合，以计算输运性质和自旋传递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.