title: Time-resolved spin-torque switching and enhanced damping in permalloy/Cu/permalloy spin-valve nanopillars.
abstract: 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.
authors.affiliation: Cornell University, Ithaca, New York 14853-2501, USA.
authors.forename: N C
authors.initials: NC
authors.lastname: Emley
authors.forename: I N
authors.initials: IN
authors.lastname: Krivorotov
authors.forename: O
authors.initials: O
authors.lastname: Ozatay
authors.forename: A G F
authors.initials: AG
authors.lastname: Garcia
authors.forename: J C
authors.initials: JC
authors.lastname: Sankey
authors.forename: D C
authors.initials: DC
authors.lastname: Ralph
authors.forename: R A
authors.initials: RA
authors.lastname: Buhrman