NMR-STUDIES OF HIGHLY POLARIZED LIQUID HE-3-HE-4 MIXTURES

An efficient technique for maintaining large He-3 nuclear spin polariz ations in liquid He-3-He-4 mixtures has been developed and used to pol arize samples contained in narrow tubes. Results obtained in a U-shape d 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 signal s obtained in the coil-shaped cell reveal phase separation and tile ex istence of a highly polarized He-3-rich region in the sample.