Self diffusion anomaly in ferromagnetic metals: A density-functional-theory investigation of magnetically ordered and disordered Fe and Co

The temperature (T) dependent self-diffusion coefficients (D) in Fe and Co are calculated from first-principles, across the Curie temperature (Tc), employing a density functional theory approach based on a recently developed spin-wave method for modeling the paramagnetic state. Calculated results for D(T) are shown to accurately reproduce measured values for T/Tc ranging from 0.7 to 1.1, including the anomaly in the Arrhenius plot for Fe near Tc. An analysis of calculated results in Mn, Fe and Co suggests that the magnitude of the effect of magnetic disorder on D is correlated with d band filling and the transition from “weak” to “strong” ferromagnetism.