Frequency dependence of coercive properties

Significant frequency dependence of domain wall coercive field, due to the widening of the hysteresis loops, was observed based on AC hysteresis curve measurements in epitaxial magnetic garnet films. Domain wall oscillation measurements did not reveal any frequency dependence. The different results of the two measurement methods were analyzed, and the observed frequency dependence was attributed to the inertia of the moving domain walls. It was shown that the real value of the domain wall pinning field cannot be determined by AC hysteresis measurements, even in non-conducting materials.