Pulsed NMR studies of superfluid³He

We present a review of our pulsed NMR experiments in the A and B phases of superfluid³He, at pressures of 23 and 27 bar. We have measured the dipole frequency in³He-A, spin susceptibility in³He-B, and tip-angle-dependent frequency shifts in both phases. In general, we find excellent agreement with results by other workers. In³He-B, complex spin motions were observed involving long-lived free induction decays with a time-dependent precession frequency. Spin relaxation measurements for both³He-A and³He-B are discussed and compared with those of other workers. After driving the magnetization far from equilibrium, anomalous frequency shifts were found to persist in the A phase. We discuss a soliton-texture model by Bruinsma and Maki which accounts for these resonances.