NONLINEAR SPIN DYNAMICS AND MAGNETIC-FIELD DISTORTION OF THE SUPERFLUID HE-3-B ORDER-PARAMETER

We have measured magnetic field distortion of the order parameter and the longitudinal resonance frequency of superfluid He-3-B using pulsed nuclear magnetic resonance. The experiments were guided by numerical solutions of Leggett's equations which we have generalized to include gap distortion. We have found stable regions for the nonlinear spin dy namics and taken advantage of this to obtain the first measurements of the temperature dependence of the distortion of the energy gap in the B phase. At low temperatures and pressures the results agree with the oretical predictions of Fishman and Sauls.