Thermal spin-transfer in Fe-MgO-Fe tunnel junctions

TL;DR

This paper calculates thermal spin transfer torques in Fe-MgO-Fe tunnel junctions, revealing significant effects at room temperature that could enable thermally induced magnetization switching and high-frequency spintronic applications.

Contribution

It provides the first principles calculation of thermal spin transfer torques in Fe-MgO-Fe junctions, highlighting the impact of multiple scattering and interface states.

Findings

Thermal spin transfer torque can cause magnetization reversal with temperature differences over 10 K.

The torque magnitude at room temperature is approximately 10^-7 J/m^2/K.

Angular dependence of TST can be highly skewed, enabling high-frequency generation.

Abstract

We compute thermal spin transfer torques (TST) in Fe-MgO-Fe tunnel junctions using a first principles wave function-matching method. At room temperature, the TST in a junction with 3 MgO monolayers amounts to 10^-7J/m^2/K, which is estimated to cause magnetization reversal for temperature differences over the barrier of the order of 10 K. The large TST can be explained by multiple scattering between interface states through ultrathin barriers. The angular dependence of the TST can be very skewed, possibly leading to thermally induced high-frequency generation.