Magnetoresistance of itinerant electrons interacting with local spins

Abstract

Transport properties of itinerant electrons interacting with local spins are analyzed as function of the bandwidth, $W$, the exchange interaction, $J$, and the band filling, $n$, near the band edge. Numerical results have been obtained within the dynamical mean-field approximation and interpreted with the help of analytical treatments. If spatial correlations of the magnetic fluctuations can be neglected, and defining $ρ(m)$ as the magnetization dependent resistivity, we find that $δρ/ ρ(0) \sim n^{-4/3}$ for $J / W, n \ll 1$ (weak coupling, low density limit), $δρ/ ρ(0) \sim constant$, for $J / W \gg 1, n \ll 1$ (double exchange, low density limit), where $δρ= \partial ρ/ \partial m^2 |_{m^2 \to 0}$. Possible limitations from ignoring both localization effects and critical fluctuations are also considered.