Magnetic properties of ferrimagnets

Magnetic properties of ferrimagnets with competing nearest- and next-nearest-neighbor interactions, J(1) and J(2) are studied. The ground-state spin configuration is determined by a variational method as a function of J(1) and J(2). Various canted spin states are found. Properties at finite temperatures in the case of collinear spin configuration for two general spin magnitudes are investigated by a Green's function method. Results of the sublattice magnetizations as well as the critical temperature are shown and compared with our Monte-Carlo simulations. Applications of our model is discussed.