Thermal conductivity of RNi/sub 2/B/sub 2/C (R=Gd, Dy, Ho, Er, Tm and Lu) systems

We have systematically studied the thermal conductivity of the quaternary nickel borocarbide compounds RNi/sub 2/B/sub 2/C (R=Gd, Dy, Ho, Er, Tm and Lu). Thermal conductivity measurements have been conducted for RNi/sub 2/B/sub 2/C systems in the temperature range from 4.2 K to 25 K, under applied magnetic fields up to 30 kOe. The temperature dependence of thermal conductivity for the superconducting samples in zero magnetic field show a small and clear decrease at their superconducting transition temperatures. In zero or lower magnetic fields, the thermal conductivity for the samples with magnetic transition show a small peak at their magnetic transition temperatures (T/sub N/ or T/sub m/), which disappear under higher applied magnetic fields. The results suggest the existence of strong electron-phonon interplay in these compounds.