title: Nonlinear magnetic vortex dynamics in a circular nanodot excited by spin-polarized current.
abstract: We investigate analytically and numerically nonlinear vortex spin torque oscillator dynamics in a circular magnetic nanodot induced by a spin-polarized current perpendicular to the dot plane. We use a generalized nonlinear Thiele equation including spin-torque term by Slonczewski for describing the nanosize vortex core transient and steady orbit motions and analyze nonlinear contributions to all forces in this equation. Blue shift of the nano-oscillator frequency increasing the current is explained by a combination of the exchange, magnetostatic, and Zeeman energy contributions to the frequency nonlinear coefficient. Applicability and limitations of the standard nonlinear nano-oscillator model are discussed.
authors.affiliation: Depto. Física de Materiales, Facultad de Química, Universidad del País Vasco, UPV/EHU, San Sebastián 20018, Spain ; IKERBASQUE, Basque Foundation for Science, Bilbao 48011, Spain.
authors.forename: Konstantin Y
authors.initials: KY
authors.lastname: Guslienko
authors.affiliation: Depto. Física de Materiales, Facultad de Química, Universidad del País Vasco, UPV/EHU, San Sebastián 20018, Spain.
authors.forename: Oksana V
authors.initials: OV
authors.lastname: Sukhostavets
authors.affiliation: General Numerics Research Laboratory, Jena 07745, Germany.
authors.forename: Dmitry V
authors.initials: DV
authors.lastname: Berkov
keywords: Magnetic nanodot; Nano-oscillator; Spin torque transfer; Vortex