Measurements of the spin diffusion coefficient of normal3He in bulk liquid and a restricted geometry

In this paper we present reliable measurements of the pressure variation of the spin diffusion coefficient of normal liquid3He in the limiting low-temperature Fermi fluid regime. Deviations from the bulk liquid behavior are observed for a sample confined to a 5-µm glass capillary array in which the mean free path of the3He quasiparticles is of the order of the capillary diameter. These deviations are believed to indicate that the spin momentum specular reflection coefficient is less than unity but greater than zero in this system.