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.
@article{arxiv.cond-mat/0510798,
title = {Time-Resolved Spin Torque Switching and Enhanced Damping in Py/Cu/Py Spin-Valve Nanopillars},
author = {N. C. Emley and I. N. Krivorotov and A. G. F. Garcia and O. Ozatay and J. C. Sankey and D. C. Ralph and R. A. Buhrman},
journal= {arXiv preprint arXiv:cond-mat/0510798},
year = {2009}
}