Simultaneous Measurements of the Torsional Oscillator Anomaly and Thermal Conductivity in Solid He-4

Zmeev, D. E. and Golov, A. I. (2011) Simultaneous Measurements of the Torsional Oscillator Anomaly and Thermal Conductivity in Solid He-4. Physical review letters, 107 (6): 065302. ISSN 0031-9007

Abstract

In these torsional oscillator experiments, the samples of solid He-4 were characterized by measuring their thermal conductivity. Polycrystalline samples of helium of either high isotopic purity or natural concentration of He-3 were grown in an annular container by the blocked-capillary method and investigated before and after annealing. No correlation has been found between the magnitude of the low-temperature shift of the torsional oscillator frequency and the amount of crystalline defects as measured by the thermal conductivity. In samples with the natural He-3 concentration, a substantial excess thermal conductivity over the usual T-3 dependence was observed below 120 mK.