Disorder-Induced Resistive Anomaly Near Ferromagnetic Phase Transitions*

Felix von Oppen

Freie Universitat Berlin

We show that the resistivity ρ(T) of disordered ferromagnets near, and above, the Curie temperature Tc 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, dρ/dT exhibits a |T-Tc|-1/2 singularity near Tc. Our results, being solely due to impurities, are relevant to ferromagnets with low Tc, such as SrRuO3 or diluted magnetic semiconductors, whose mobility near Tc is limited by disorder.

*Carsten Timm, M. E. Raikh, Felix von Oppen, Phys. Rev. Lett. 94, 036602 (2005).