Temperature dependence of the resistivity in the double-exchange model

The resistivity around the ferromagnetic transition temperature in the doub le-exchange model is studied by the Schwinger-boson approach. The spatial s pin correlation responsible for scattering of conduction electrons are take n into account by adopting the memory function formalism. Although the corr elation shows a peak lower than the transition temperature, the resistivity in the ferromagnetic state monotonically increases with increasing tempera ture due to a variation of the electronic state of the conduction electron. In the paramagnetic state, the resistivity is dominated by the short-range correlation of scattering and is almost independent of the temperature. It is attributed to a cancellation between the nearest-neighbor spin correlat ion the fermion bandwidth, and the fermion kinetic energy. This result impl ies the importance of the temperature dependence of the electronic states o f the conduction electron as well as the localized spin states in both ferr omagnetic and paramagnetic phases. [S0163-1829(99)08313-7].