Mn1-xFexCoGe: A strongly correlated metal in the proximity of a noncollinear ferromagnetic state

Abstract

An unusually large Kadowaki–Woods ratio of A/γ2 ∼ 43 μΩ·cm·mol2·K2·J−2 has been observed for intermetallic Mn1-xFexCoGe compounds in the proximity of x = 0.2 where the magnetic state of itinerant electrons system changes. The ratio is approximately four times larger than observed for heavy fermion systems. The manifestation of the strong electron correlations can be realized from the anisotropic origin of the effect through the substantial reduction of interlayer transport of heavy quasiparticles with comparable mean-free path and interlayer spacing in the proximity of a noncollinear ferromagnetic state associated with a large density of states at the Fermi level.