Disorder-Induced Resistive Anomaly Near Ferromagnetic Phase Transitions

TL;DR

This paper demonstrates that disorder causes a resistive anomaly near the ferromagnetic transition temperature, exceeding traditional predictions, with a specific singularity in resistivity derivative due to impurities.

Contribution

It reveals a disorder-induced resistive anomaly near T_c that surpasses Fisher-Langer predictions, using mean-field theory beyond Boltzmann transport.

Findings

Resistivity derivative dρ/dT shows a |T−T_c|^{-1/2} singularity near T_c.

Anomaly is solely due to impurities, relevant for low T_c ferromagnets.

Results apply to materials like SrRuO3 and diluted magnetic semiconductors.

Abstract

We show that the resistivity rho(T) of disordered ferromagnets near, and above, the Curie temperature T_c generically exhibits a stronger anomaly than the scaling-based Fisher-Langer prediction. Treating transport beyond the Boltzmann description, we find that within mean-field theory, d\rho/dT exhibits a |T-T_c|^{-1/2} singularity near T_c. Our results, being solely due to impurities, are relevant to ferromagnets with low T_c, such as SrRuO3 or diluted magnetic semiconductors, whose mobility near T_c is limited by disorder.