Asymmetric magnetic disorder observed in thermally activated magnetization reversal of exchange-biased IrMn/CoFe films

作者：Lee Hun Sung; Ryu Kwang Su; You Chun Yeol; Jeon Kun Rok; Yang See Hun; Parkin Stuart S P; Shin Sung Chul^*

来源：Journal of Magnetism and Magnetic Materials, 2013, 325: 13-16.

DOI：10.1016/j.jmmm.2012.07.038

• Exchange-bias
• Magnetic disorder
• Asymmetry
• Thermally activated reversal behavior
• Domain wall motion

We report an asymmetry of magnetic disorder in exchange-biased IrMn(t(IrMn) = 5-20 nm)/CoFe(50 nm) films observed by means of a Kerr microscope, capable of direct domain observation. From the correlation between the magnetization half-reversal time and applied magnetic field, we find that the magnetization switching in all the films occurs via a thermally activated reversal mechanism for both branches of hysteresis loops. Surprisingly, in the forward branch reversal where the applied magnetic field is antiparallel to the direction of exchange-bias field, degree of magnetic disorder decreases as exchange-bias field increases, which is definitely contrasted with the case of backward branch reversal. This result is likely ascribed to the fact that the local values of exchange-bias field and coercive field are oppositely fluctuating with each other in the film.

• 出版日期2013-1
• 单位IBM