Polar Phase of $$^3$$He in Nematic Aerogel and Quartz Tuning Fork as Sensitive Detectors of Surface Boundary Conditions

Abstract

A new superfluid phase of $$^3$$ He, a polar phase, which is known to stabilize in nematic aerogel, has already led to the observation of many new phenomena. One important condition for the existence of the polar phase is a $$^4$$ He coverage, which removes solid paramagnetic $$^3$$ He from the surface of the aerogel strands. We report here the results of NMR experiments with superfluid $$^3$$ He in nematic aerogel demonstrating the influence of $$^4$$ He coverage. Simultaneous measurements of resonance properties of a quartz tuning fork immersed in liquid $$^3$$ He well correlate with the NMR data.