ON A CUSP IN THE MAGNETIC-FIELD VELOCITY DEPENDENCE FOR DOMAIN-WALL MOTION IN RARE-EARTH ORTHOFERRITES

Using the Landau-Lifshitz equations and the equation for acoustic waves, a formula describing the steps in the dependence of domain-wall velocity upsilon on external magnetic field H is obtained. The analysis leads to the conclusion that a 'break' can be observed in the maximum of the H(upsilon) dependence (i.e. a jump in the differential mobility of the domain wall) caused by a change in the contribution of long-wavelength acoustic waves to the dissipation function. An approximation for the H(upsilon) dependence describing such a jump is proposed. The possibility of the existence of a second maximum on the H(upsilon) curve at velocities less than the speed of sound is demonstrated.