Note on the Ground States of Systems with the Strong Hund-Coupling

Abstract

The effect of the strong Hund coupling on the magnetic property of the ground stateis studied based on the double exchange model. For one dimensional chains the ground state is proved to have the maximum total spin. The effect of the Pauli principle is shown to destroy the ferromagnetic ground state by numerical studies of finite loops. The result is extended to a model with degenerate bands.