NMR Properties of Spin-Polarised HELIUM-3-HELIUM Solutions

Available from UMI in association with The British Library. Requires signed TDF. In this thesis the results of nuclear magnetic resonance experiments on 2.6%, 1.4%, 0.56% and 0.1% solutions of ^3He in ^4He are reported. Measurements were performed in high fields of 10 Tesla and in moderate fields of 2 Tesla over the temperature range 10-500 mK. Spin echoes were observed over the entire temperature range and multiple spin echoes (MSEs) were observed in each case at temperatures below 40 mK. Values for D, the Spin Diffusion Coefficient, and muM_{rm o}, the Spin Rotation Parameter, were measured self consistently in three ways; from echo heights and echo phases, by fitting to the Leggett-Rice equations; and from MSE heights using the theory of Bedford et al. From the ratio of μm _{rm o}/D against temperature it was possible to obtain a value of lambda /(1 + F_{rm o}^ {rm a}) for each concentration used, where muM_{rm o} = omegalambdatau . Here omega is the Larmor frequency, tau is the transverse relaxation time and lambda is a combination of Fermi liquid parameters. The values of lambda /(1 + F_{rm o}^ {rm a}) obtained in this way were plotted against concentration, together with the values of Candela et al, Ishimoto et al, and Owers-Bradley et al. From these data it was possible to obtain the ^3He-^3He scattering length, a, which was found to be -0.93 +/- 0.02 A. This result is discussed in relation to other values of a, determined both theoretically and from other experiments. A long timescale ringing, of tens of milliseconds in duration, was observed during the high field experiments which is similar to that observed by Nunes et al.