Spin-polaron model: Transport properties of EuB6

Abstract

To understand anomalous transport properties of EuB6, we have studied the spin-polaron Hamiltonian incorporating the electron-magnon and electron-phonon interactions. Assuming a strong exchange interaction between carriers and the localized spins, the electrical conductivity is calculated. The temperature and magnetic-field dependences of the resistivity of EuB6 are well explained. At low temperature, magnons dominate the conduction process, whereas the lattice contribution becomes significant at very high temperature due to the scattering with the phonons. Large negative magnetoresistance near the ferromagnetic transition is also reproduced as observed in EuB6.