Effect of noise on the high-speed reversal of single-domain uniaxial magnetic nanoparticles

Abstract

The effect of noise on the reversal of a single-domain uniaxial magnetic nanoparticle is studied on the basis of computer simulation of the Landau-Lifshits equation. The interplay between resonant activationlike and noise-delayed switching effects is investigated. Namely, it is demonstrated that for the dipole reversal by the pulse with smooth fronts, there exists the optimal pulse width, which minimizes the mean reversal time MRT and the standard deviation SD. Both the MRT and the SD significantly depend on the angle between the reversal magnetic field and the anisotropy axis. In comparison with the uniaxial symmetry case at the optimal angle =45°, the MRT can be decreased from a factor of seven up to two orders of magnitude, and the jitter can be decreased from one to three orders of magnitude for damping ranging from 1 to 0.01. It is demonstrated that for =5° the increase in temperature from 4 to 300 K leads to doubling the MRT due to the noise-delayed switching effect.