Electronic band effects on the spin disorder resistivity of Gd(4)(Co(1-x)Cu(x))(3) compounds

We present a study of the spin disorder resistivity ([Formula: see text]) and the electronic specific heat coefficient (γ) in Gd(4)(Co(1-x)Cu(x))(3) compounds, with x = 0.00, 0.05, 0.10, 0.20 and 0.30. The experimental results show a strongly nonlinear dependence of [Formula: see text] on the average de Gennes factor (G(av)) which, in similar intermetallic compounds, is usually attributed to the existence of spin fluctuations on the Co 3d bands. Values of γ were found around 110 mJ mol(-1) K(-2) for the Gd(4)(Co(1-x)Cu(x))(3) compounds, much larger than 38.4 mJ mol(-1) K(-2) found for the isostructural nonmagnetic Y(4)Co(3) compound. Using a novel type of analysis we show that the ratio [Formula: see text] follows a well-defined linear dependence on G(av), which is expected when appropriate dependencies with the effective electron mass are taken into account. This indicates that band structure effects, rather than spin fluctuations, could be the main cause for the strong electron scattering and γ enhancement observed in the Gd(4)(Co(1-x)Cu(x))(3) compounds. A discussion on relevant features of magnetization and electrical resistivity data, for the same series of compounds, is also presented.