Are superparamagnetic spins classical?
Statistical Mechanics
2009-11-13 v1 Materials Science
Abstract
Effective giant spins of magnetic nanoparticles are considered classically in the conventional theory of superparamagnetism based on the Landau-Lifshitz-Langevin equation. However, microscopic calculations for a large spin with uniaxial anisotropy, coupled to the lattice via the simplest generic mechanism, show that the results of the conventional theory are not reproduced in the limit S ->\infty. In particular, the prefactor Gamma_0 in the Arrhenius escape rate over the barrier Gamma =Gamma_0 exp[-Delta U/(k_B T)] has an anomalously large sensitivity to symmetry-breaking interactions such as transverse field
Keywords
Cite
@article{arxiv.0806.2892,
title = {Are superparamagnetic spins classical?},
author = {D. A. Garanin},
journal= {arXiv preprint arXiv:0806.2892},
year = {2009}
}
Comments
6 EPL pages, 3 figure captions