Self Consistent NEGF-LLG Model for Spin-Torque Based Devices

TL;DR

This paper introduces a self-consistent quantum transport and magnetization dynamics model to analyze spin-torque devices, demonstrating potential for low-power, non-volatile memory applications with hysteretic switching behavior.

Contribution

It develops a combined NEGF-LLG model for spin-torque devices, enabling detailed analysis of current-induced magnetic switching in ballistic transport regimes.

Findings

Device exhibits hysteretic I-V characteristics at room temperature

Switching current can be reduced by an order of magnitude

Device functions as a non-volatile memory

Abstract

We present here a self consistent solution of quantum transport, using the Non Equilibrium Green's Function (NEGF) method, and magnetization dynamics, using the Landau-Lifshitz-Gilbert (LLG) formulation. We have applied this model to study current induced magnetic switching due to `spin torque' in a device where the electronic transport is ballistic and the free magnetic layer is sandwiched between two anti-parallel ferromagnetic contacts. The device shows clear hysteretic current-voltage characteristics, at room temperature, with a sharp transition between the bistable states and hence can be used as a non-volatile memory. We show that the proposed design may allow reducing the switching current by an order of magnitude.