Reversal time of jump-noise magnetization dynamics in nanomagnets via Monte Carlo simulations

Arun Parthasarathy, Shaloo Rakheja

Research output: Contribution to journalArticle

Abstract

The jump-noise is a nonhomogeneous Poisson process which models thermal effects in magnetization dynamics, with special applications in low temperature escape rate phenomena. In this work, we develop improved numerical methods for Monte Carlo simulation of the jump-noise dynamics and validate the method by comparing the stationary distribution obtained empirically against the Boltzmann distribution. In accordance with the Néel-Brown theory, the jump-noise dynamics display an exponential relaxation toward equilibrium with a characteristic reversal time, which we extract for nanomagnets with uniaxial and cubic anisotropy. We relate the jump-noise dynamics to the equivalent Landau-Lifshitz dynamics up to second order correction for a general energy landscape and obtain the analogous Néel-Brown theory's solution of the reversal time. We find that the reversal time of jump-noise dynamics is characterized by Néel-Brown theory's solution at the energy saddle point for small noise. For large noise, the magnetization reversal due to jump-noise dynamics phenomenologically represents macroscopic tunneling of magnetization.

Original languageEnglish (US)
Article number223901
JournalJournal of Applied Physics
Volume123
Issue number22
DOIs
StatePublished - Jun 14 2018

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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