NMR measurement of quantized vortex lines in rotating He-3-A

The dominant vortex line in He-3-A has singularity-free order parameter str ucture and low-critical velocity. It is formed in magnetic fields above 1 m T, where the orbital and spin parts of the order parameter are "unlocked", it carries two quanta of circulation (= 2 kappa(0)), and gives rise to a fr equency-shifted satellite peak in the NMR absorption spectrum. We have meas ured its NMR response with improved resolution and find that the satellite amplitude, in addition to being proportional to the number of vortex lines, also includes a small texture-dependent contribution. (C) 2000 Published b y Elsevier Science B.V. All rights reserved.