Time-Resolved Spin Torque Switching and Enhanced Damping in Py/Cu/Py Spin-Valve Nanopillars

TL;DR

This study investigates the temperature-dependent spin torque switching and damping in Py/Cu/Py nanopillars, revealing the influence of an antiferromagnetic oxide layer on magnetic dynamics.

Contribution

It provides the first time-resolved measurements of spin torque switching in Py/Cu/Py nanopillars and links damping behavior to an antiferromagnetic pinning layer.

Findings

Damping increases significantly with decreasing temperature.

Antiferromagnetic pinning layer affects spin torque phenomena.

Simulation results match experimental data for damping and torque.

Abstract

We report time-resolved measurements of current-induced reversal of a free magnetic layer in Py/Cu/Py elliptical nanopillars at temperatures T = 4.2 K to 160 K. Comparison of the data to Landau-Lifshitz-Gilbert macrospin simulations of the free layer switching yields numerical values for the spin torque and the Gilbert damping parameters as functions of T. The damping is strongly T-dependent, which we attribute to the antiferromagnetic pinning behavior of a thin permalloy oxide layer around the perimeter of the free layer. This adventitious antiferromagnetic pinning layer can have a major impact on spin torque phenomena.