Electrical resistance anomaly in normal rare earth systems

Anomalous behavior of the magnetic part of rare-earth intermetallic resistivity in the paramagnetic phase is analyzed as an effect of free electron scattering on collective excitations in magnetic ion system. A simple model of Boltzmann equation formalism with the Born approximation for the resistivity and molecular field-random phase approximation (MFA-RPA) for the excitation spectra is used. We show that the negative temperature coefficient of the resistivity above certain temperature TmaxTmax, close to or considerably greater than the magnetic phase transition temperature TcTc, is a manifestation of the magnetic excitations critical behavior. The anomaly conditions are formulated and the crystal field splitting influence on TmaxTmax is estimated. The analysis is based on the resistivity calculations for REIn3REIn3 (RE=GdRE=Gd, Tb, Tm) and their comparison to experimental data.