Low-temperature thermoelectric transport properties of selected metals and dielectrics

Abstract

Reliable and accurate estimate of experimentally measured thermal conductivity values are presented in this work for specific materials, which carries significant importance from low temeprature application perspecive. In this regard, the thermal conductivities for copper RRR≈14 and 2014 aluminum alloy are reported within the temperature ranges of 10 K to 390 K, whereas alumina and hexagonal boron nitride materials are tested within the 10 K to 300 K. Besides this, the electrical resistivity, the Seebeck coefficient, as well as the thermoelectric figure of merit of copper and 2014 aluminum are also presented over the entire temperature range of 10–390 K. All of these properties are measured simultaneously by using Quantum Design (QD) Dynacool thermal transport option, that posseses accurate temperature control with greater degree of flexibilty in handling various material specimens. The thermal conductivity of copper has shown a diverse maximum with its purity level. The electronic conductivity calculated using Wiedemann- Franz is analyzed to highlight the electronic and lattice wave contributions to the thermal conductivity. The temperature-dependent Lorenz ratios are presented for the direct estimation of thermal conductivity using available electrical resistivity values. Finally, the material-specific, temperature-dependent correlations are proposed to estimate these properties, which can be readily used to estimate temperature-dependent transport properties.