Role of geometrical symmetry in thermally activated processes in clusters of interacting dipolar moments
Role of geometrical symmetry in thermally activated processes in clusters of interacting dipolar moments
Thermally activated magnetization decay is studied in ensembles of clusters of interacting dipolar moments by applying the master-equation formalism, as a model of thermal relaxation in systems of interacting single-domain ferromagnetic particles. Solving the associated master equation reveals a breakdown of the energy barrier picture depending on the geometrical symmetry of structures. Deviations are most pronounced for reduced symmetry and result in a strong interaction dependence of relaxation rates on the memory of system initialization. A simple two-state system description of an ensemble of clusters is developed, which accounts for the observed anomalies. These results follow from a semianalytical treatment, and are fully supported by kinetic Monte Carlo simulations.
104410
Hovorka, O.
a12bd550-ad45-4963-aa26-dd81dd1609ee
Barker, J.
78f47f76-9d49-45b2-9788-6c667a435c26
Friedman, G.
db2affbf-29bf-4a43-8e55-01b388d54c23
Chantrell, R.W.
2df0bd37-172a-4d0b-892a-2c78b6dc3fc3
12 March 2014
Hovorka, O.
a12bd550-ad45-4963-aa26-dd81dd1609ee
Barker, J.
78f47f76-9d49-45b2-9788-6c667a435c26
Friedman, G.
db2affbf-29bf-4a43-8e55-01b388d54c23
Chantrell, R.W.
2df0bd37-172a-4d0b-892a-2c78b6dc3fc3
Hovorka, O., Barker, J., Friedman, G. and Chantrell, R.W.
(2014)
Role of geometrical symmetry in thermally activated processes in clusters of interacting dipolar moments.
Physical Review B, 89, .
(doi:10.1103/PhysRevB.89.104410).
Abstract
Thermally activated magnetization decay is studied in ensembles of clusters of interacting dipolar moments by applying the master-equation formalism, as a model of thermal relaxation in systems of interacting single-domain ferromagnetic particles. Solving the associated master equation reveals a breakdown of the energy barrier picture depending on the geometrical symmetry of structures. Deviations are most pronounced for reduced symmetry and result in a strong interaction dependence of relaxation rates on the memory of system initialization. A simple two-state system description of an ensemble of clusters is developed, which accounts for the observed anomalies. These results follow from a semianalytical treatment, and are fully supported by kinetic Monte Carlo simulations.
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e-pub ahead of print date: 1 March 2014
Published date: 12 March 2014
Organisations:
Faculty of Engineering and the Environment
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Local EPrints ID: 381832
URI: http://eprints.soton.ac.uk/id/eprint/381832
ISSN: 1550-235X
PURE UUID: 8f627fcc-f090-49dc-817a-c34f90582afa
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Date deposited: 30 Sep 2015 16:08
Last modified: 15 Mar 2024 03:48
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Author:
J. Barker
Author:
G. Friedman
Author:
R.W. Chantrell
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