Magnetic dissipation in superfluid He-3-B in the transition regime to nonhydrodynamic conditions

We have applied the so-called HPD spectroscopy, i.e. the NMR of the homogeneously precessing domain (HPD) in superfluid He-3-B, to study the magnetic relaxation processes down to 0.3T(c). The power absorbed by HPD from cw NMR rf-field was divided into several contributions corresponding to different relaxation processes. From these contributions nonhydrodynamic corrections to spin diffusion and Leggett-Takagi (L-T) relaxation were extracted for a pressure of 6 bar. Below 0.45T(c) a large absorption term linear with the HPD length and increasing with the falling temperature was observed. This term could be associated with an instability of coherent precession in the nonhydrodynamic regime. The process of the HPD formation in the nonwetting regime, for T < 0.37T(c), was observed and described leading to a new possibility to determine the d-constant of the surface energy.