Low frequency acoustics in solid ${}^4$He at low temperature

Abstract

The elastic properties of hcp ${}^4$He samples have been investigated using low frequency (20 Hz to 20 kHz) high sensitivity sound transducers. In agreement with the findings of other workers, most samples studied grew very significantly stiffer at low temperature; Poisson's ratio $\nu$ was observed to increase from 0.28 below 20 mK to $\sim 0.35$ at 0.7 K. The span of the variation of $\nu$ varies from sample to sample according to their thermal and mechanical history. Crystals carefully grown at the melting curve show a different behavior, the change in $\nu$ taking place at lower $T$ and being more abrupt.

References in corpus (5)

• What makes a crystal supersolid ?
• Nonclassical Rotational Inertia in Single Crystal Helium
• Thermal History of Solid 4He Under Oscillation
• Solid 4He and the Supersolid Phase: from Theoretical Speculation to the Discovery of a New State of Matter? A Review of the Past and Present Status of Research
• Search for supersolidity in 4He in low-frequency sound experiments

Cited by in corpus (6)

• ${}^4$He Crystal Quality and Rotational Response in a Transparent Torsional Oscillator
• Interpreting Torsional Oscillator Measurements: Effect of Shear Modulus and Supersolidity
• A glass anomaly in the shear modulus of solid ${}^4$He
• The low temperature elastic anomalies in solid helium
• Plastic response by dislocation glide in solid helium under dc strain rate loading
• ${}^4$He in Nanoporous Media: 4D XY Quantum Criticality at Finite Temperatures