ANISOTROPIC SPIN-DIFFUSION IN A SATURATED HE-3-HE-4 SOLUTION

We have measured both the longitudinal and transverse spin diffusion c oefficients, D-parallel to and D-perpendicular to , in a saturated mix ture of He-3 in He-4 (He-3 concentration x(3) = 6.4%) in a magnetic fi eld of 8.8 T in the temperature range 11 less than or equal to T less than or equal to 500 mK. Consequently we are able to provide direct ev idence for the anisotropy in spin diffusion predicted by Meyerovich. B elow similar to 30 mK, D-parallel to varies as T-2 in accordance with the predictions of Landau Fermi-liquid theory; but D-perpendicular to becomes smaller than D-parallel to at the lowest temperatures resultin g in an anisotropy factor D-parallel to/D-perpendicular to of 4 at T = 11 mK. We believe that this large anisotropy is due to a breakdown of the standard Landau Fermi-liquid theory in concentrated mixtures of H e-3 in He-4. Finally we use our measurements of the spin rotation para meter, mu M(0), along with results from previous experiments at variou s He-3 concentrations to deduce a value for the quasiparticle scatteri ng length a= -0.88+/-0.05 Angstrom.