Journal of Statistical Physics

, Volume 60, Issue 3, pp 473–484

First-passage-time approach to overbarrier relaxation of magnetization

  • Ivo Klik
  • Leon Gunther

DOI: 10.1007/BF01314931

Cite this article as:
Klik, I. & Gunther, L. J Stat Phys (1990) 60: 473. doi:10.1007/BF01314931


We consider the irreversible dynamics of the magnetization vectorM in a single-domain particle. The dynamics is given by a stochastic phenomenological equation due to Gilbert. It contains a damping field proportional toM and a corresponding white noise field component. The probability distribution function satisfies a Fokker-Planck equation derived by Brown. We give the overbarrier decay rateκ out of a metastable minimum. First we rederive the well-known expression forκ for an axially symmetric model. We argue that this result is unphysical. For systems of general point symmetry of the magnetic anisotropy energy we giveκ in both the low-damping and intermediate- to high-damping limits.

Key words

First passage timesmagnetization relaxationsuperparamagnets

Copyright information

© Plenum Publishing Corporation 1990

Authors and Affiliations

  • Ivo Klik
    • 1
  • Leon Gunther
    • 1
  1. 1.Department of Physics and AstronomyTufts UniversityMedford