Disorder effects on the metastability of classical Heisenberg ferromagnets

Abstract

In the present work, we investigate the effects of disorder on the reversal time ($\tau$) of classical anisotropic Heisenberg ferromagnets in three dimensions by means of Monte Carlo simulations. Starting from the pure system, our analysis suggests that $\tau$ increases with increasing anisotropy strength. On the other hand, for the case of randomly distributed anisotropy, generated from various statistical distributions, a set of results is obtained: (i) For both bimodal and uniform distributions the variation of $\tau$ with the strength of anisotropy strongly depends on temperature. (ii) At lower temperatures, the decrement in $\tau$ with increasing width of the distribution is more prominent. (iii) For the case of normally distributed anisotropy, the variation of $\tau$ with the width of the distribution is non-monotonic, featuring a minimum value that decays exponentially with the temperature. Finally, we elaborate on the joint effect of longitudinal ($h_z$) and transverse ($h_x$) fields on $\tau$, which appear to obey a scaling behavior of the form $\tau h_z^n\sim f(h_x)$.

arXiv comment18 pages preprint style, 10 figures, including Appendix, version to be published in Phys Rev E

References in corpus (7)

• Magnetization switching in a Heisenberg model for small ferromagnetic particles
• Nucleation and hysteresis in Ising model: Classical theory versus computer simulation
• The anisotropic Heisenberg chain in coexisting transverse and longitudinal magnetic fields
• Effects of random fields on the reversal of magnetisation of Ising ferromagnet
• Metastable behavior of the spin-s Ising and Blume-Capel ferromagnets: A Monte Carlo study
• Metastability in graded and step like variation of field and anisotropy of the Blume-Capel ferromagnet
• Anisotropy driven reversal of magnetisation in Blume-Capel ferromagnet: A Monte Carlo study

Cited by in corpus (1)

• Equilibrium and Nonequilibrium phase transitions in continuous symmetric classical magnets