Europhys. Lett.
Volume 48, Number 5, December 1999
Page(s) 486 - 490
Section General
Published online 01 September 2002
DOI: 10.1209/epl/i1999-00509-0

Europhys. Lett, 48 (5), pp. 486-490 (1999)

New integral relaxation time for thermal activation of magnetic particles

D. A. Garanin

Max-Planck-Institut für Physik komplexer Systeme
Nöthnitzer Str. 38, D-01187 Dresden, Germany

(received 10 May 1999; accepted in final form 28 September 1999)

PACS. 05.40$\rm -a$ - Fluctuation phenomena, random processes, noise, and Brownian motion.
PACS. 75.50Tt - Fine-particle systems.


The integral relaxation time for the difference of numbers of particles in the two potential wells (IRT-N) for double-well classical spin systems is introduced. For the uniaxial symmetry, it is given by a quadrature. Unlike the previously introduced integral relaxation time for the magnetization, the IRT-N at low temperatures describes the rate of crossing the barrier under all conditions, including the strongly biased case. In the high-barrier case, the new integral relaxation time approaches the inverse of the lowest eigenvalue of the Fokker-Planck equation $\Lambda_1$. It can be more conveniently found by numerical methods than the latter.


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