He-3 superfluidity in the presence of aerogel

Aerogels introduce disorder into the F-wave-paired superfluid He-3 and supp ress T-c, Quantifiable (by small angle N-ray scattering) differences in the long-range structure of two identical density aerogels are primarily respo nsible for their different transition temperatures. We also demonstrate tha t alteration of the short-range correlations by the addition of He-4 does n ot strongly affect T-c. Acoustic measurements of the fast and slow modes of He-3 in aerogel are described. These can be used to explore the superfluid component. We also outline future prospects. (C) 2000 Elsevier Science B.V . All rights reserved.