Nonstationary forced motion of domain walls in ferrimagnets near the spin compensation point

Abstract

The motion of domain walls in ferrimagnets near the sublattice spin compensation point is studied theoretically, when there is an exchange enhancement in the limiting velocity of the wall. Nonlinear regimes of high-velocity nonstationary wall motion are found. A magnet parameter region in which the collective variable approach is invalid, is detected. In this region, the wall motion is accompanied by the periodic appearance of instability with respect to the increase in spin oscillations inside the domain wall.