Anisotropy, exchange coupling and phase transition in bilayer systems

Abstract

Phase transitions in magnetic multilayer structures are studied with mean-field theory. Transitions between different magnetization configurations in bilayer systems with different anisotropies are discussed by means of variational method. The responsible mechanism is the competition between the anisotropy energy and the exchange coupling. The para-ferro magnetic phase transition in a ferromagnetic bilayer system is investigated with the Ginzburg-Landau theory. The effect of finiteness of the layer thickness has been revealed. Critical phenomena according to the variance of the layer thickness are clarified.