Nuclear magnetic resonance study of normal and superfluid 3He

We report on nuclear magnetic resonance studies of normal and superfluid 3He. The normal fluid work extended previous measurements of the susceptibility from 30 mK to 3 mK, in order to more accurately determine the limiting value of the susceptibility. We took all the data in a single pressure sweep, from 26 to 0.5 bar. We use these values of the susceptibility along with previously published results for the specific heat to determine the Fermi-liquid parameter FoA. We find excellent agreement with the extrapolation of the previous work to lower temperatures. In superfluid 3He-B we made measurements of the g-shift as a function of susceptibility at a pressure of 1 bar and frequencies of 3.87 and 5.82 MHz. The data were fit to a theory which indicates that the Fermi-liquid parameter F2A has a value of 0.1 at low pressure. This is compared with various other estimates. We also calculate the Landau-Ginsburg parameter β345 and find poor agreement with other estimates. We also measured the open-quotes magic tipping angleclose quotes (the tipping angle in superfluid 3He -B where one expects to see a large change in the precession frequency). Contrary to expectations, we find that it does not change as the sample warms to Tc. While performing these experiments we observed two new and unexpected effects-the existence of a small negative frequency shift for tipping angles between 90 degrees and 104 degrees, and the existence of a new mode of ringing with a large (400 Hz) frequency shift, seen at large tipping angles