Effect of a hard-magnetic surface layer in domain structures in the region of spontaneous spin-reorientation phase transition in erbium orthoferrite plates

The rearrangement of domain structures in erbium orthoferrite plates with a hard-magnetic surface layer has been visually investigated and explained on the basis of proposed physical models. It is shown that, when the temperature of such plates approaches the temperature range of spin reorientation, the surface energy density of the domain walls separating the internal and surface domains decreases, resulting in a transition to domain structures that are close to equilibrium.