Magnetoresistance of itinerant electrons interacting with local spins

TL;DR

This paper investigates how the resistivity of itinerant electrons interacting with local spins varies with bandwidth, exchange interaction, and band filling, using numerical and analytical methods within the dynamical mean-field approximation.

Contribution

It provides a detailed analysis of magnetoresistance behavior in different coupling and density regimes, extending understanding of transport in magnetic materials.

Findings

Resistivity change scales as n^{-4/3} in weak coupling, low-density limit.

Resistivity change approaches a constant in strong coupling, low-density limit.

Neglecting localization and critical fluctuations may limit the applicability of results.

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