QUANTUM APPROACH FOR MAGNETIC MULTILAYERS AT FINITE TEMPERATURES

The Green's function technique has been employed to examine the finite -temperature properties of a magnetic multilayer both in aligned and i n canted spin configurations. A local coordinates system is introduced to describe complicated spin configurations which are determined by m inimizing the free energy of the magnetic multilayer. Thermal averages of S-m(Zm) in each layer are selected to be independent variables: an d the necessarily self-consistent equations are obtained successfully based on the random phase approximation. The temperature dependences o f the coercivity, the hysteresis, and the magnetic multivalued recordi ng have been discussed, and an application of the present approach to the canted spin state is given in a double-film system.