The initial stage in the nonlinear motion of a domain wall in garnet films

A study of the domain-wall motion in single-crystal garnet films of the YBiFeGa system with a perpendicular magnetic anisotropy, activated by a constant in-plane bias field Hp parallel to the wall plane and a pulsed drive field Hg of an amplitude corresponding to the nonlinear region of the domain-wall velocity vs. the Hg relation is reported. The earlier data suggesting the existence of an initial phase of motion, where the wall is accelerated to a high instantaneous velocity, have been confirmed. The wall behavior in the initial phase has been shown to be affected by the field Hp and the drive-field pulse rise time. A possible mechanism of the wall structure transformation after the application of the Hg pulse is considered. It has been established that the dependence of the wall velocity on Hp in the saturation region disagrees with theory.