Thermal and charge conductivities of superconducting skutterudite compounds, PrRu4Sb12 and PrOs4Sb12

Abstract

The measurement of thermal conductivity is a powerful probe that can be used for identifying the nature of heat and charge carriers and structure of the gap in the superconducting compounds. At low temperature when the effect of phonons in transporting heat becomes smaller, one can obtain information about the quasiparticle distribution and the superconducting gap structure.

In order to do a sensitive thermal conductivity measurement, we designed and built a thermal conductivity mount. The charge conductivity was measured through the same leads that we used for making the thermal conductivity measurements. To test the mount, we measured the heat and charge conductivity of a silver wire and determined the accuracy with which we could satisfy the Wiedemann--Franz law within 5 \%.

We will report the measurements of thermal and electrical conductivities of two filled skutterudite superconducting compounds, PrRu4Sb12 and PrOs4Sb12 at 1.1--35 K temperature range. The differences and similarities between the transport properties of these compounds in the superconducting and normal states along with the results of investigation of the Wiedemann--Franz law will be discussed in the following chapters.