Role of geometrical symmetry in thermally activated processes in clusters of interacting dipolar moments

O. Hovorka; J. Barker; G. Friedman; R.W. Chantrell

doi:10.1103/PhysRevB.89.104410

Role of geometrical symmetry in thermally activated processes in clusters of interacting dipolar moments

O. Hovorka, J. Barker, G. Friedman, R.W. Chantrell

Physics

Research output: Contribution to journal › Article › peer-review

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.

Original language	English
Article number	104410
Journal	Physical Review B: Condensed Matter and Materials Physics
Volume	89
Issue number	10
DOIs	https://doi.org/10.1103/PhysRevB.89.104410
Publication status	Published - 12 Mar 2014

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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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AU - Barker, J.

AU - Friedman, G.

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Role of geometrical symmetry in thermally activated processes in clusters of interacting dipolar moments

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