D-f hybridization and quantum criticality in weakly-itinerant ferromagnets

Abstract

We investigate the unusual magnetic, thermodynamic and transport properties of nearly-critical, weakly-itinerant ferromagnets with the general formula UTX, where T=Rh, Co and X=Ge, Si. As a unique feature of these systems, we show how changes in the Vdf hybridization, which controls their proximity to a ferromagnetic instability, determine the evolution of the ground state magnetization, M0, the Curie temperature, TC, the density of states at the Fermi level, N(EF), the T2 resistivity coefficient, A, and the specific heat coefficient, γ. The universal aspect of our findings comes from the dependence on only two parameters: the transition metal Td bandwidth, Wd, and the distance between the Td and Uf band centers, CTd - CUf. We discuss our results in connection to data for URh1-xCoxGe. © 2013 IOP Publishing Ltd.