Rotating Superfluid 3He in Aerogel

Rotational effects on textures of superfluid 3He in aerogel with 98% porosity at a pressure 3.0 MPa were investigated by cw-NMR measurement at 700 kHz (H0=22 mT) under rotation up to 2π rad/s. At rest, the superfluidtransition to the A phase occurred at Taerogelc=2.07 mK and the A phase was supercooled down to TaerogelA→B==1.73∼1.80 mK and became the B phase in the cooling process. In the warming process, the B phase was superheated up to Taerogelc. In the B phase, a new peak appeared in the NMR spectrum by rotating the sample. The intensity of this peak increased as the rotation speed increased almost linealy to Ω and started to be saturated for Ω≥Ωc. We attributed the new peak to the textural change caused by the counter flow and the onset of the saturation at Ωc to the onset of vortex nucleation in aerogel. On deceleration, the peak intensity decreased and disappeared at Ω=Ωv. Further decreasing Ω, the peak intensity increased even at Ω=0. The counterflow peak observed at Ω=0 indicates the existence of persistent current induced by pinned vortices in aerogel. In the A phase, we did not find any noticeable change in the NMR spectrum under the rotation speed up to 2π rad/s, or by cooling through Tc with or without rotation. We concluded that the \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $${\hat \ell }$$ \end{document} texture in the A phase was strongly pinned to aerogel. No spin wave satellite signal localized at a soft, core vortex was observed in contrast to the bulk A phase.