Spin Disorder Resistivity and Electronic Specific Heat of Gd4(Co1-xCux)3 Compounds

In this work, we present a study of the spin disorder resistivity ( ρm∞) and the electronic specific heat coefficient ( γ) in Gd4(Co1-xCux)3 compounds, with x = 0, 0.05, 0.10, 0.20, 0.30. The experimental results show a strongly non-linear dependence of ρm∞ on the de Gennes factor which, in similar intermetallic compounds, is usually attributed to the existence of spin fluctuations on the Co 3d bands and its amplification by the thermal disorder of the Gd magnetic moments through the Gd-Co exchange coupling. Using a novel combined analysis of ρm∞ and γ, we show, however, that only electron band structure changes are involved in the anomalous behaviour of ρm∞ and that a linear dependence of ρm∞ on the de Gennes factor is obtained when the variation of the effective mass is properly taken into account.