Numerical Study on Spin Torque Switching in Thermally Activated Region

TL;DR

This paper numerically investigates spin torque switching in thermally activated regimes, revealing a nonlinear temperature dependence of switching time and challenging the assumption that the current exponent is unity, aiding in thermal stability assessment.

Contribution

It demonstrates that the current exponent in the switching rate formula is not necessarily unity, providing a more accurate model for thermal stability in spintronics devices.

Findings

Switching time dependence on temperature is nonlinear.

The exponent b in the switching rate formula is not equal to 1.

Results improve understanding of thermal stability in spintronics.

Abstract

We studied the spin torque switching of the single free layer in the thermally activated region by numerically solving the Landau-Lifshitz-Gilbert equation. We found that the temperature dependence of the switching time of the in-plane magnetized system is nonlinear, which means $b \neq 1$. Here, $b$ is the exponent of the current term in the switching rate formula and has been widely assumed to be unity. This result enables us to evaluate the thermal stability of spintronics devices.