Magnon modes for a magnetic disk in a cone vortex state
V.A. Uzunova1 and B.A. Ivanov2,3
1Institute of Physics of the National Academy of Sciences 46 Nauki Ave., Kiev 03028, Ukraine
2Institute of Magnetism, NASU, 36-B Vernadskii Ave., Kiev 03142, Ukraine
3National Taras Shevchenko University of Kiev, Kiev 03127, Ukraine
Received August 8, 2018, published online November 26, 2018
The easy-cone phase is realized as the ground state of uniaxial magnets with comparable second-order and fourth-order anisotropy constants. In such systems, specific vortex states, the cone-vortex state, can exist. The oscillations of the magnetization in small cylindrical particles in the cone vortex state are studied. The frequencies of magnon excitations on a background of a vortex in the cone phase of a ferromagnet are found. A significant splitting of the doublets of the modes with opposite values of the azimuthal number m, including modes with |m|> 1, is discovered.
Key words: magnetic vortex, easy-cone state, gyroscopic mode, magnetic anisotropy, spin waves.