Nonlinear motion of magnetization in superfluid3He-B. The Leggett-Takagi spin relaxation effect in the pulsed NMR configuration

The recovery motion of the magnetization and the associated motion of the order parameter for the pulsed NMR geometry in superfluid³He-B are investigated by solving the Brinkman equations including the Leggett-Takagi spin relaxation effect. It is found that the relaxation of longitudinal magnetization strongly depends upon the initial tip angles according to both the numerical and adiabatic perturbation methods. For large tip angles, these equations yield square-root and linear types of recovery. For small tip angles near the magic angle ₀=cos^–1 (–1/4), the longitudinal magnetization does not recover to the full equilibrium value, and the transverse magnetization shows time-dependent resonance shifts arising from the relaxation effect.