Thermally activated magnetization reversal behavior of uniaxial ferromagnetic thin films in the microsecond to second time regime

Abstract

We investigate the thermally activated magnetization reversal of Co/Pd multilayers with uniaxial perpendicular anisotropy using a magneto-optical Kerr effect microscope capable of direct domain observation in a wide time range of microsecond to second. It is found that the energy barrier in the thermally activated process is nonlinearly dependent on the applied field, irrespective of the difference in the domain evolution processes of wall motion, dendrite growth, and nucleation. These results are well explained by a theoretical model considering a ferromagnetic thin film with uniaxial perpendicular anisotropy.