Spin-lattice dynamics model with angular momentum transfer for canonical and microcanonical ensembles

Mara Strungaru*, Matthew O.A. Ellis, Sergiu Ruta, Oksana Chubykalo-Fesenko, Richard F.L. Evans, Roy W. Chantrell

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


A unified model of molecular and atomistic spin dynamics is presented enabling simulations both in microcanonical and canonical ensembles without the necessity of additional phenomenological spin damping. Transfer of energy and angular momentum between the lattice and the spin systems is achieved by a phenomenological coupling term representing the spin-orbit interaction. The characteristic spectra of the spin and phonon systems are analyzed for different coupling strength and temperatures. The spin spectral density shows magnon modes together with the uncorrelated noise induced by the coupling to the lattice. The effective damping parameter is investigated showing an increase with both coupling strength and temperature. The model paves the way to understanding magnetic relaxation processes beyond the phenomenological approach of the Gilbert damping and the dynamics of the energy transfer between lattice and spins.

Original languageEnglish
Article number024429
JournalPhysical Review B
Issue number2
Publication statusPublished - 19 Jan 2021

Bibliographical note

Funding Information:
We are grateful to Dr. P.-W. Ma and Professor M. Probert for helpful discussions. Financial support of the Advanced Storage Research Consortium is gratefully acknowledged. M.O.A.E. gratefully acknowledges support in part from EPSRC through Grant No. EP/S009647/1. The spin-lattice simulations were undertaken on the VIKING cluster, which is a high performance compute facility provided by the University of York. The authors acknowledge the networking opportunities provided by the European COST Action CA17123 "Magnetofon" and the short-time scientific mission awarded to M.S.

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