The transport properties of RCo₂compounds

Abstract

The transport properties of intermetallic compounds RCo2 (R=Pr, Nd, Sm, Gd-Lu, Sc and Y) in the temperature range from 4.2 up to 1000 K were studied and different contributions were determined. In the non-magnetic compounds the spin fluctuation contribution to the electrical resistivity, rho sf varies as (T/Tsf)2, and thermal resistivity, Wsf varies as (T/Tsf), were found to follow the theoretical predictions. The spin disorder contribution arising from the scattering of conduction electrons on 4f moments was deduced and found to be proportional to the de Gennes factor. It is shown that the spin fluctuations are responsible for the low-temperature features of the temperature-dependent thermopower, whereas the high-temperature behaviour is mainly determined by the density of states function. In the paramagnetic region near the Curie temperature, the critical fluctuations cause a considerable enhancement of the electrical resistivity of the magnetic RCo2 compounds, which is manifested by pronounced upturns in rho versus T dependences.