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

We investigate resistive anomalies in metals near a ferromagnetic phase transition, emphasizing the role of long-range critical fluctuations. Our analysis shows that electron diffusion near the critical temperature T_{c} enhances the singular behavior of resistivity via a classical memory effect, exceeding the prediction of Fisher and Langer [Phys. Rev. Lett. 20, 665 (1968)PRLTAO0031-900710.1103/PhysRevLett.20.665]. Close to T_{c}, the resistivity develops a cusp or anticusp controlled by the critical exponent of the order parameter. We also express a concomitant non-Drude behavior of the optical conductivity in terms of critical exponents. These results provide deeper insight into the origin of resistive anomalies and their connection to criticality in metallic systems.