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Microscopic theory for the Markovian decay of magnetization fluctuations in nanomagnets

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journal contribution
posted on 09.08.2018, 10:04 by Ioannis RousochatzakisIoannis Rousochatzakis
We present a microscopic theory for the phonon-driven decay of the magnetization fluctuations in a wide class of nanomagnets where the dominant energy is set by isotropic exchange and/or uniaxial anisotropy. Based on the Zwanzig-Mori projection formalism, the theory reveals that the magnetization fluctuations are governed by a single decay rate ωc, which we further identify with the zero-frequency portion of the associated self-energy. This dynamical decoupling from the remaining slow degrees of freedom is attributed to a conservation law and the discreteness of the energy spectrum and explains the omnipresent monoexponential decay of the magnetization over several decades in time, as observed experimentally. A physically transparent analytical expression for ωc is derived which highlights the three specific mechanisms of the slowing-down effect which are known so far in nanomagnets. © 2007 The American Physical Society.

History

School

  • Science

Department

  • Physics

Published in

Physical Review B - Condensed Matter and Materials Physics

Volume

76

Issue

21

Citation

ROUSOCHATZAKIS, I., ... et al., 2007. Microscopic theory for the Markovian decay of magnetization fluctuations in nanomagnets. Physical Review B - Condensed Matter and Materials Physics, 76: 214431.

Publisher

© American Physical Society (APS)

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2007

Notes

This paper was accepted for publication in the journal Physical Review B - Condensed Matter and Materials Physics and the definitive published version is available at https://doi.org/10.1103/PhysRevB.76.214431

ISSN

1098-0121

eISSN

1550-235X

Language

en

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