Equal-spin-pairing superfluid phase of 3He in an aerogel acting as an impurity

The superfluid phases of 3He in a 97.5% porosity aerogel have been studied using cw and pulsed NMR techniques at several pressures. The equilibrium equal-spin-paring superfluid phase, A-like phase region is observed very near Tcaero, and that region normalized with Tcaero is found to be independent of pressure in contrast with that of the bulk A phase. Tipping angle dependent frequencies in the free induction decay signal of the A-like phase are quite different from those of the bulk A phase. On these grounds, we propose that the A-like phase in aerogel is a different superfluid phase and can be described as a robust state introduced by Fomin [JETP Lett. 77, 240 (2003)]