Year: 2011
Type: article
Abstract: Using an apparatus that allows superfluid liquid ${}^{4}$He to be in contact with hcp solid ${}^{4}$He at pressures greater than the bulk melting pressure of the solid, we have performed experiments that show evidence for ${}^{4}$He mass flux through the solid and the likely presence of superfluid inside the solid. We present results that show that a thermomechanical equilibrium in quantitative agreement with the fountain effect exists between two liquid reservoirs connected to each other through two superfluid-filled Vycor rods in series with a chamber filled with solid ${}^{4}$He. We use the thermomechanical effect to induce flow through the solid and measure the flow rate. On cooling, mass flux appears near $T=600$ mK and rises smoothly as the temperature is lowered. Near $T=75$ mK a sharp drop in the flux is present. The flux increases as the temperature is reduced below 75 mK. We comment on possible causes of this flux minimum.
Source: Physical Review B
Authors: M. W. Ray, R. B. Hallock
Institution: University of Massachusetts Amherst
Language: Latvian
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: National Science Foundation
OpenAlex ID: W2083312968