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 $\ddot{I}(m)$ as the magnetization dependent resistivity, we find that $\hat{I}´\ddot{I}/\ddot{I}(0)\sim n^{-4/3}$ for $J/W,n\ll 1$ (weak coupling, low density limit), $\hat{I}´\ddot{I}/\ddot{I}(0)\sim constant$, for $J/W\gg 1,n\ll 1$ (double exchange, low density limit), where $\hat{I}´\ddot{I}=\partial \ddot{I}/\partial m^2{|}_{m^2\to 0}$. Possible limitations from ignoring both localization effects and critical fluctuations are also considered.

7 pages