Simultaneous measurements of the torsional oscillator anomaly and thermal conductivity in solid 4He

In these torsional oscillator experiments, the samples of solid (4)He were characterized by measuring their thermal conductivity. Polycrystalline samples of helium of either high isotopic purity or natural concentration of (3)He 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 (3)He concentration, a substantial excess thermal conductivity over the usual T(3) dependence was observed below 120 mK.