Influence of coercive force on low-frequency creep in bloch-wall permalloy films

A very high resolution Bitter pattern technique is used to observe the motion of Bloch walls in Permalloy films excited by slowly rising and slowly falling hard-axis fields. For low coercive force films, the basic motion consists of approximately equal and opposite jumps induced by simultaneous wall structure changes at two transition fields. Net motion begins with the application of small easy-axis bias fields. For high coercive force films, although the wall structure changes continue to occur, the wall jumps and a net displacement do net occur until the easy-axis bias field exceeds a certain critical value which is a function of the wall coercive force.