Time Dependence Of Magnetization Reversal Influenced By Current In Perpendicularly Magnetized Co/Pt Thin Film

We have investigated thermally activated magnetization reversal influenced by the current in a Co/Pt thin film with perpendicular magnetic anisotropy at room temperature by measuring the extraordinary Hall effect. The magnetization could reverse in a fixed magnetic field lower than the coercive field as increasing the current, which depends on the current-sweep rate. The characteristic current for zero net magnetization is small for a low current-sweep rate and a high fixed field. Magnetization reversal becomes fast for a high current-sweep rate and a high fixed field. With the constant current, the magnetization reversal is fast for a large current and a high fixed field. The magnitude of the propagation field H-P* reduces more than 70 Oe when the current density J reaches 1.25 x 10(5) A/cm(2), which is mainly on account of the sample temperature rise due to current-induced Joule heating. Also, the effective field HI associated with spin transfer and momentum transfer perhaps has a contribution to magnetization reversal through thermal activation in a multidomain macroscopic thin film. The results show that the Joule heating and current associated effective field can reduce the activation energy barriers and speed up magnetization reversal besides the applied magnetic field. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3002419]