A study of low-frequency creep in bloch-wall permalloy films

A very high resolution Bitter pattern technique is used to study low-frequency creep in Bloch-wall Permalloy films. The basic wall motion consists of a sudden displacement when the hard-axis exciting field passes through two critical transition values. A net displacement per half-cycle or slow pulse occurs in the presence of an easy-axis bias. The motion appears to be gyro-magnetically induced by the precession of the magnetization in the wall about a demagnetizing field perpendicular to the wall plane. The demagnetizing field may be produced by an instability in the relation between the hard-axis field and the magnetization in the domains on sides of the wall rather than in the wall.