Europhys. Lett., 76 (6), pp. 1001-1007 (2006)
DOI: 10.1209/epl/i2006-10403-3

Mean first-passage times for an ac-driven magnetic moment of a nanoparticle

S. I. Denisov^{1, 2}, K. Sakmann¹, P. Talkner¹ and P. Hänggi<sup>1

1</sup>  Institut für Physik, Universität Augsburg - Universitätsstraße 1 D-86135 Augsburg, Germany
²  Sumy State University - 2 Rimsky-Korsakov Street, 40007 Sumy, Ukraine

received 21 August 2006; accepted in final form 30 October 2006
published online 29 November 2006

Abstract
The two-dimensional backward Fokker-Planck equation is used to calculate the mean first-passage times (MFPTs) of the magnetic moment of a nanoparticle driven by a rotating magnetic field. It is shown that a magnetic field that is rapidly rotating in the plane perpendicular to the easy axis of the nanoparticle governs the MFPTs just in the same way as a static magnetic field that is applied along the easy axis. Within this framework, the features of the magnetic relaxation and net magnetization of systems composed of ferromagnetic nanoparticles arising from the action of the rotating field are revealed.

PACS
05.10.Gg - Stochastic analysis methods (Fokker-Planck, Langevin, etc.).
75.60.Jk - Magnetization reversal mechanisms.
75.50.Tt - Fine-particle systems; nanocrystalline materials.

© EDP Sciences 2006