Correlation Between the Field-Driven Microscopic Magnetization Reversal and the Disorders in Ferromagnetic Systems

Understanding the field-driven microscopic magnetization reversal in a disordered ferromagnetic (FM) film is a fundamentally intriguing issue for the application of a disorder-induced magnetic memory. We present the field dependence of the correlation between local coercivity and switching time in the FM films showing two typical reversal processes: wall-motion and nucleation dominant ones. As the applied field strength increases, the correlation coefficient in the wall-motion sample decreases, whereas the one in the nucleation sample holds nearly zero value. The change in the wall-motion sample is well explained by the transition of the magnetization reversal mechanism from a thermal activation reversal to a viscous motion. This paper shows that the magnetization reversal mechanism depending on the time scale as well as the materials has a strong influence on the correlation.