title: Direct observation of spin-torque driven magnetization reversal through nonuniform modes.
abstract: We present time-resolved x-ray images with 30 nm spatial and 70 ps temporal resolution, which reveal details of the spatially resolved magnetization evolution in nanoscale samples of various dimensions during reversible spin-torque switching processes. Our data in conjunction with micromagnetic simulations suggest a simple unified picture of magnetic switching based on the motion of a magnetic vortex. With decreasing size of the magnetic element the path of the vortex core moves from inside to outside of the nanoelement, and the switching process evolves from a curled nonuniform to an increasingly uniform mode.
authors.affiliation: Department of Applied Physics, Stanford University, Stanford, California 94305, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Strachan
authors.forename: V
authors.initials: V
authors.lastname: Chembrolu
authors.forename: Y
authors.initials: Y
authors.lastname: Acremann
authors.forename: X W
authors.initials: XW
authors.lastname: Yu
authors.forename: A A
authors.initials: AA
authors.lastname: Tulapurkar
authors.forename: T
authors.initials: T
authors.lastname: Tyliszczak
authors.forename: J A
authors.initials: JA
authors.lastname: Katine
authors.forename: M J
authors.initials: MJ
authors.lastname: Carey
authors.forename: M R
authors.initials: MR
authors.lastname: Scheinfein
authors.forename: H C
authors.initials: HC
authors.lastname: Siegmann
authors.forename: J
authors.initials: J
authors.lastname: Stöhr