Lattice Constants, Electrical Resistivity and Specific Heat of RNiC₂

Abstract

Anomalous temperature dependence of electrical resistivity was found to be ubiquitous among the compounds RNiC 2 with R = La, Ce, Nd, Sm, Gd, Tb and Er. Lattice parameters were also observed to exhibit anomalous temperature dependence for some of the compounds studied by X-ray diffraction. It is argued that the existence of charge modulated structures is the cause of the former anomalies. The latter anomalies, on the other hand, are likely to be related to the coupling between the lattice and the f-electrons. Results of heat capacity measurements are used to estimate crystal field levels in NdNiC 2 and SmNiC 2 .