Spin-polarization dependent carrier diffusion—a study of the CMR effect in manganese perovskite
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文摘
A theory based on spin-polarization dependent carrier diffusion is developed to study the transport behaviors, including colossal magnetoresistance effect, in manganese perovskites R–A–Mn–O (R: rear earth; A: metals with a valence of two or one). Starting from Hubbard–Kondo Hamiltonian and using a mean-field method, we have derived the double exchange energy between neighboring Mn ions. Then using the notion of carrier diffusion, a relation of resistivity versus temperature, concentration and normalized magnetization has been obtained for the hole-doped manganese perovskite. By the simple relation, most of the transport behaviors reported, including the magnetoresistance, in the manganese perovskite have been successfully simulated.