TRANSIENT STATE AND STEADY-STATE MAGNETIZ ATION IN A ONE-DIMENSIONAL MAGNETIC UNDER APPLICATION OF MAGNETIC-FIELD

The authors consider the response of the uniaxial two-sublattice and t he biaxial one-sublattice X-Y models to steplike change of external ma gnetic field oriented along the z axis. It is shown that in certain si tuations (the biaxial one-sublattice X-Y model in the ground state, th e initial field intensity tending to infinity) the magnitude of the ma gnetization alteration does not depend on the final field value. Besid es, it is shown that the dynamic susceptibility of the biaxial one-sub lattice X-Y model, unlike the static susceptibility, has a jump at a c ertain value of the field at non-zero temperature.