${}^4$He Crystal Quality and Rotational Response in a Transparent Torsional Oscillator

A. D. Fefferman, X. Rojas, A. Haziot +3

We have studied natural purity ${}^4$He single crystals and polycrystals between 10 and 600 mK using a torsional oscillator with a 2 cm${}^3$ rigid cell made of sapphire with a smo…