Superfluidity of 3He contained in aerogel

It is known that the critical temperature of superfluid He-3 confined within aerogel is suppressed, however, the exact nature of the superfluid phase is currently undetermined. We have designed an experiment in which the aerogel is surrounded by bulk superfluid of a known phase. Owing to the dipole-dipole interaction the bulk superfluid precesses at a frequency shifted from the Larmor frequency. The surface solid and the confined liquid components of the He-3 inside the aerogel are in fast exchange and precess near the Larmor frequency. We have observed an additional NMR signal near the frequency of the bulk He-3 from the aerogel. (C) 2000 Elsevier Science B.V. All rights reserved.