Metastable states of the ring domain structure

Abstract

The structure of concentric ring domains in a cylindrical specimen and its change with magnetic field H are studied by computation, and the results are compared with those of analogous investigations of plane domain structures in rectangular and ellipsoidal specimens. Common to all three cases is the existence of metastable states caused by magnetostatic barriers between states with different numbers of domain walls N; the essential influence of these barriers on the character of the dependence of N or H; the possibility of asymmetry of the magnetization curve and of the existence of remanent magnetization in an equilibrium state. Common to the ring structure and the plane domain structure in a rectangular specimen is the existence of an intermediate phase transition corresponding to changing N in fields less than the saturation field. Common to the ring structure and the plane domain structure in an ellipsoidal specimen are jump-like phase transitions corresponding to the changing N in the magnetization process and the possibility of the existence of metastable states of a domain structure at H ≠ 0 for specimens where only a single-domain state is possible at H = 0.