Effect of the Molecular Field on the Electrical Resistivity Near a Magnetic Transition: GdNi2

We have measured the temperature dependence of the electrical resistivity of the cubic, Laves-phase, ferromagnetic, intermetallic compounds Gd${\mathrm{Ni}}_2$, Gd${\mathrm{Pt}}_2$, and Gd${\mathrm{Rh}}_2$, and for Gd${\mathrm{Ni}}_2$, we have analyzed the temperature derivative of the electrical resistivity in the neighborhood of the magnetic transition. Above the Curie temperature our data are very well described by the molecular-field treatment of the long-range spin fluctuations of the short-range order, giving for the first time an experimental result in agreement with this treatment.