3He in Aerogel – an Inhomogeneously Disordered Unconventional Superfluid

We have examined the superfluidity of3He in 98.2% porous silica aerogel with up to 34% 4He at 21.6 bar. The mixture is phase-separated for4He fractions between ∼ 11% and 34%. The4He-rich, phase preferentially occupies the regions of highest silica density in the aerogel, thus modifying the distribution of the correlated disorder seen by superftuid3He. The3He Tcincreases slightly with4He content while the superfluid fraction decreases rapidly. This behavior is inconsistent with that of3He in a homogeneously scattering medium and is analogous to that of a granular superconductor.