Resistive Anomaly near a Ferromagnetic Phase Transition: A Classical Memory Effect

Abstract

We investigate resistive anomalies in metals near ferromagnetic phase transitions, focusing on the role of long-range critical fluctuations. Our analysis reveals that diffusive motion of electrons near the critical temperature ($T_c$) enhances a singular behavior of the resistivity near $T_c$ through a classical memory effect, surpassing the prediction by Fisher and Langer \cite{Fisher:1968}. We show that, close enough to $T_c$, the resistivity exhibits a cusp or anticusp, whose profile is controlled by the critical exponent of the order parameter. We also parameterize the non-Drude behavior of the optical conductivity due to a classical memory effect in terms of critical exponents. These findings offer a deeper understanding of resistive anomalies and their connection to critical exponents in metallic systems.