Precipitous Onset for Superfluidity inHe3-He4Mixtures

Abstract

The precipitous onset step of Kosterlitz, Thouless, and Nelson has been investigated in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ mixture films over the temperature range 1.3 K to $T_{\lambda }$. The constant relating the minimum value of superfluid density to the absolute temperature is found experimentally to be universal up to 30% ${}_{}{}^3{}_{}{}^{}\mathrm{He}$. Comparison is made with recent mixture theories. Measurements were made at 24 MHz with a quartz microbalance adsorptometer.