NUCLEAR MAGNETIC-SUSCEPTIBILITY OF 2D SOLID HELIUM ISOTOPIC MIXTURES

The nuclear magnetic susceptibility of two dimensional solid helium is otopic mixtures, formed by a submonolayer film adsorbed on the surface of graphite, has been measured down to 2mK. He-3 concentrations in th e range 1% to 16%, at total surface densities above 0.082angstrom-2 we re explored. At the higher concentrations there is clear evidence of a phase transition, in agreement with previous measurements. The presen t results suggest that this corresponds to incomplete phase separation . At lower concentrations no signature of phase separation has yet bee n detected. The deviations from Curie law, attributable to quantum dif fusion of He-3, are greatest at 0.086angstrom-2.