Spin Transport in Dilute, SpinPolarized Solutions of HeliumThree in HeliumFour
Abstract
We have investigated ^3He spin diffusion in two dilute solutions of ^3 He in ^4He, with atomic fraction x^3=1.82times 10^{3} and 6.26 times 10 ^{4}, spinpolarized by an 8 T field. We do not find evidence that the diffusion coefficient for spins transverse to the average magnetization (D _) declines or saturates at temperatures down to 0.20T_{rm F}, contrary to previous experiment (Gully and Mullin 1984) but in accord with current theory. We have compared our measurements with the latest theory of Jeon and Mullin (1991); our data is mostly in good agreement with their theory if a slightly modified version of a ^3 He^3He interaction due to Ebner (1967) is used. The congruence between data and theory supports the conclusion that the swave approximation to the interaction is not useful for transport calculations even for these rather dilute solutions. There may be an one unresolved discrepancy: our diffusion constant for the lowest concentration at the lowest temperatures is 25% higher than theory predicts. This could be due to a polarization dependance for D_ or to a modification of the boundary condition by a bound ^3He state, or possibly due to errors in the theoretical calculation.
 Publication:

Ph.D. Thesis
 Pub Date:
 January 1992
 Bibcode:
 1992PhDT.......138M
 Keywords:

 HELIUM;
 FERMI LIQUIDS;
 Physics: Fluid and Plasma; Physics: Atomic