Observation of vortex-creep in superfluid 3He B-like phase in aerogel by the HPD

Superfluid 3He A-like and B-like phases in 98% aerogel have been studied under rotation up to 2π rad/s by using cw-NMR and Homogeneous Pressing Domain (HPD) NMR at 29 mT and 3.0 MPa. We studied the dissipation of the HPD in aerogel and found that the HPD-mode was destroyed by onset of the thermal runaway for sufficient large sample under a large field gradient. From the field dependence of the onset of thermal runaway, we estimated dissipation of the HPD in aerogel and compared with that of the bulk B-phase. When angular velocity of rotation goes beyond Ωc, vortices are introduced and pinned. We estimate roughly the excess dissipation due to vortices and compare it with that of vortices in bulk B-phase.