Peculiar spin echo in thick He-3 films on boron nitride

Results are reported for pulsed NMR studies of thick films (25 layers) of H e-3 physisorbed on carefully prepared hexagonal boron nitride substrates. P eculiar doublet structures in the NMR spin-echo shapes have been observed f or temperatures 0.9 less than or equal to T less than or equal to 1.2 K. Th ese echo shapes are interpreted in terms of a two-component system: (a) a s olid phase (up to 4.6 layers) near the substrate, and (b) a liquid phase ne ar the free surface of the film.