Dynamics of interphase domain walls during a Morin-type phase transition

The dynamics of 90-degree interphase domain walls during a first-order Mori n-type spin-reorientation phase transition is studied theoretically. It is shown that an oscillatory motion of the walls with an amplitude that depend s linearly on the field amplitude, as well as a drift motion of the wall at a velocity proportional to the square of the field amplitude, are driven b y an external oscillating magnetic field. Drift of the entire domain struct ure as a whole is predicted to be possible. (C) 1999 American Institute of Physics. [S1063-7834(99)01702-5].