Temperature increase in STT-MRAM at writing: A fully three-dimensional finite element approach

Abstract

The writing process in spin transfer torque magnetoresistive random access memories is facilitated by elevated temperatures. In this work we investigate the temperature in the free layer (FL) during switching. With our fully three-dimensional (3D) finite element method simulation approach, we numerically solve the heat transport equation coupled to the electron, spin, and magnetization dynamics and demonstrate that the FL temperature is highly inhomogeneous due to non-uniform magnetization of the FL during switching. While the average temperature in the FL can be obtained based on an average current density and an averaged potential drop across the tunnel barrier in a one-dimensional model, a fully 3D model is required to evaluate the large local temperature variations.