Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Article number | 065302 |
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<mark>Journal publication date</mark> | 5/08/2011 |
<mark>Journal</mark> | Physical review letters |
Issue number | 6 |
Volume | 107 |
Number of pages | 5 |
Publication Status | Published |
Early online date | 2/08/11 |
<mark>Original language</mark> | English |
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.