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Dynamic origin of azimuthal modes splitting in vortex-state magnetic dots.

Research paper by Konstantin Y KY Guslienko, Andrei N AN Slavin, Vasyl V Tiberkevich, Sang-Koog SK Kim

Indexed on: 31 Dec '08Published on: 31 Dec '08Published in: Physical review letters



Abstract

A spin-wave theory explaining experimentally observed frequency splitting of dynamical spin excitations with azimuthal symmetry of a magnetic dot in a vortex ground state is developed. It is shown that this splitting is a result of the dipolar hybridization of three spin-wave modes of a dot having azimuthal indices |m|=1: two high-frequency azimuthal dipolar modes of the in-plane part of the vortex with indices m = +/-1 and a low-frequency (Goldstone-like) gyrotropic mode, describing translational motion of the vortex core and having index m = +1. The analytically calculated magnitude of the frequency splitting is proportional to the ratio of the dot thickness to its radius and quantitatively agrees with the results of time-resolved Kerr experiments.