Time-resolved spin-torque switching and enhanced damping in permalloy/Cu/permalloy spin-valve nanopillars.
We report time-resolved measurements of current-induced reversal of a free magnetic layer in Permalloy/Cu/Permalloy 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 presence of an antiferromagnetic oxide layer around the perimeter of the Permalloy free layer. This adventitious antiferromagnetic oxide can have a major impact on spin-torque phenomena.
Emley
N C
NC
Cornell University, Ithaca, New York 14853-2501, USA.
Krivorotov
I N
IN
Ozatay
O
O
Garcia
A G F
AG
Sankey
J C
JC
Ralph
D C
DC
Buhrman
R A
RA