NMR studies of highly polarized liquid 3He-4He mixtures

An efficient technique for maintaining large 3He nuclear spin polarizations in liquid 3He-4He mixtures has been developed and used to polarize samples contained in narrow tubes. Results obtained in a U-shaped cell and a coil-shaped cell are compared. A systematic study of the effects of dipolar fields within the sample on the characteristics of the observed long-lived magnetostatic modes is in progress. NMR signals obtained in the coil-shaped cell reveal phase separation and the existence of a highly polarized 3He-rich region in the sample