Lattice Thermal Conductivity of Deformed Copper-Aluminum Alloy Crystals at Low Temperatures

Abstract

Phonon scattering by dislocations at liquid helium temperature has been studied by measuring the thermal conductivity of Cu-15 at % Al alloy crystals deformed by various amounts. Curves of lattice thermal conductivity vs. temperature plotted in log-log scale are concave upwards in the temperature range between 1.6∼4.2°K. These experimental data cannot be described by the scattering of phonons by the static strain field around dislocations through anharmonicity. The result is interpreted by assuming resonance scattering due to vibrating edge dislocations in their Cottrell atmospheres in addition to the scattering due to electron-phonon interaction.