Asymmetric stochasticity of magnetization reversal dynamics in exchange-biased IrMn/CoFe Film

Abstract

In this study, we investigated the stochastic nature of domain reversal dynamics in exchange-biased IrMn/CoFe film using a time-resolved Kerr microscope. Interestingly, the statistical distributions of the magnetization half-reversal times for both forward and backward applied fields show that the magnetization reversal dynamics is much more stochastic for the backward branch, where an applied field is parallel to the exchange-bias field direction. The enhanced stochasticity is ascribed to the large degree of magnetic disorder during backward reversal, which induces discrete and random Barkhausen jumps, whereas the forward branch reversal is dominated by a thermally activated depinning process caused by a single potential barrier. This result can be explained by the asymmetry of the magnetic disorder between both branches of a hysteresis loop. © 2012 American Institute of Physics.