Exchange-mediated, nonlinear, out-of-plane magnetic field dependence of the ferromagnetic vortex gyrotropic mode frequency driven by core deformation
Exchange-mediated, nonlinear, out-of-plane magnetic field dependence of the ferromagnetic vortex gyrotropic mode frequency driven by core deformation
We have performed micromagnetic simulations of low-amplitude gyrotropic dynamics of magnetic vortices in the presence of spatially uniform out-of-plane magnetic fields. For disks having small lateral dimensions, we observe a frequency drop-off when approaching the disk's out-of-plane saturation field. This nonlinear frequency response is shown to be associated with a vortex core deformation driven by nonuniform demagnetizing fields that act on the shifted core. The deformation results in an increase in the average out-of-plane magnetization of the displaced vortex state (contrasting the effect of gyrofield-driven deformation at low field), which causes the exchange contribution to the vortex stiffness to switch from positive to negative. This generates an enhanced reduction of the core stiffness at high field, leading to a nonlinear field dependence of the gyrotropic mode frequency.
1-10
Fried, Jasper P.
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Fangohr, Hans
9b7cfab9-d5dc-45dc-947c-2eba5c81a160
Kostylev, Mikhail
987113b2-474b-4b97-a51b-51e81ed79e83
Metaxas, Peter J.
422e8ca8-6e4a-48cb-b7eb-1e11a73361e3
Fried, Jasper P.
641d5106-8d01-48a9-bf90-c9fc448e803f
Fangohr, Hans
9b7cfab9-d5dc-45dc-947c-2eba5c81a160
Kostylev, Mikhail
987113b2-474b-4b97-a51b-51e81ed79e83
Metaxas, Peter J.
422e8ca8-6e4a-48cb-b7eb-1e11a73361e3
Fried, Jasper P., Fangohr, Hans, Kostylev, Mikhail and Metaxas, Peter J.
(2016)
Exchange-mediated, nonlinear, out-of-plane magnetic field dependence of the ferromagnetic vortex gyrotropic mode frequency driven by core deformation.
Physical Review B, 94 (22), , [224407].
(doi:10.1103/PhysRevB.94.224407).
Abstract
We have performed micromagnetic simulations of low-amplitude gyrotropic dynamics of magnetic vortices in the presence of spatially uniform out-of-plane magnetic fields. For disks having small lateral dimensions, we observe a frequency drop-off when approaching the disk's out-of-plane saturation field. This nonlinear frequency response is shown to be associated with a vortex core deformation driven by nonuniform demagnetizing fields that act on the shifted core. The deformation results in an increase in the average out-of-plane magnetization of the displaced vortex state (contrasting the effect of gyrofield-driven deformation at low field), which causes the exchange contribution to the vortex stiffness to switch from positive to negative. This generates an enhanced reduction of the core stiffness at high field, leading to a nonlinear field dependence of the gyrotropic mode frequency.
Text
1605.01830.pdf
- Accepted Manuscript
More information
Accepted/In Press date: 9 May 2016
e-pub ahead of print date: 7 December 2016
Organisations:
Computational Engineering & Design Group
Identifiers
Local EPrints ID: 405623
URI: http://eprints.soton.ac.uk/id/eprint/405623
ISSN: 1550-235X
PURE UUID: d42ab05f-35f0-4cc2-8be9-1b64e22d00ef
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Date deposited: 08 Feb 2017 16:17
Last modified: 16 Mar 2024 03:09
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Contributors
Author:
Jasper P. Fried
Author:
Mikhail Kostylev
Author:
Peter J. Metaxas
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