Dependence of Magnetization Reversal Behavior in Co/Ni Multilayers on Ni Top Layer Thickness

In this study, the magnetization reversal change according to the change in the thickness of the Ni upper layer was observed in the Co/Ni multilayer thin film, using a magneto-optic Kerr magnetometer capable of measuring the magnetic hysteresis curve and the magnetic viscosity curve while adjusting the direction of the magnetic field. First, as a result of measuring the hysteresis curve, the magnetization reversal of the sample showed a tendency to move the domain wall, and it was found that the magnitude of the coercive force increased as the thickness of the Ni upper layer changed from 7.5 & ANGS; to 12.5 & ANGS;. In addition, as a result of measuring the magnetic viscosity curve according to the size of the magnetic field, it was found that the magnetization reversal behaviors of all samples were well explained by the thermal activation model, and the thermal activation volume decreased as the thickness of the Ni upper layer increased from 7.5 & ANGS; to 12.5 & ANGS;.