Self-consistent simulation of quantum transport and magnetization dynamics in spin-torque based devices

Sayeef Salahuddin, Purdue University - Main Campus
Supriyo Datta, Network for Computational Nanotechnology, Birck Nanotechnology Center, and Purdue University

Abstract

This letter presents a self-consistent solution of quantum transport, using the nonequilibrium Green’s function method, and magnetization dynamics, using the Landau-Lifshitz-Gilbert formulation. This model is applied to study “spin-torque” induced magnetic switching in a device where the transport is ballistic and the free magnetic layer is sandwiched between two antiparallel AP ferromagnetic contacts. A hysteretic current-voltage characteristic is predicted at room temperature, with a sharp transition between the bistable states that can be used as a nonvolatile memory. It is further shown that this AP pentalayer device may allow significant reduction in the switching current, thus facilitating integration of nanomagnets with electronic devices.