Electronic structure and effective Hamiltonian in perovskite Mn oxides

In order to investigate electronic and magnetic structures in perovskite Mn oxides, we consider the effective Hamiltonian derived from the generalized ferromagnetic Kondo-Hubbard model. The mean-field approximation is adopted to analyze the ordered states of the spin and orbital degrees of freedom in the insulating state. As the excitations in the ordered states, we consider the spin and orbital waves and their dispersion relations are calculated.