$^4$He Crystal Quality and Rotational Response in a Transparent Torsional Oscillator
Other Condensed Matter
2015-06-03 v2
Abstract
We have studied natural purity He single crystals and polycrystals between 10 and 600 mK using a torsional oscillator with a 2 cm rigid cell made of sapphire with a smooth geometry. As the temperature was lowered, we observed sample dependent but reproducible resonant frequency shifts that could be attributed to a supersolid fraction of order 0.1%. However, these shifts were observed with single crystals, not with polycrystals. Our results indicate that, in our case, the rotational anomaly of solid helium is more likely due to a change in stiffness than to supersolidity. This interpretation would presumably require gliding of dislocations in more directions than previously thought.
Cite
@article{arxiv.1112.5998,
title = {$^4$He Crystal Quality and Rotational Response in a Transparent Torsional Oscillator},
author = {A. D. Fefferman and X. Rojas and A. Haziot and S. Balibar and J. T. West and M. H. W. Chan},
journal= {arXiv preprint arXiv:1112.5998},
year = {2015}
}