Ultrasound study of the solid-liquid transition and solid-liquid interface of ${}^4$He in aerogels

Koichi Matsumoto, Hiroyuki Tsuboya, Keiichi Yoshino +3

The freezing and melting of ${}^4$He in various aerogels with porosities ranging from 92 to 97% was studied using longitudinal ultrasound. The freezing pressure, detected by a chan…