Relaxation of polarized nuclei in superconducting rhodium

Nuclear spin lattice relaxation rates were measured in normal and supercond ucting (sc) rhodium with nuclear polarizations up to p = 0.55. This was suf ficient to influence the sc state of Rh, whose T, and B-c, are exceptionall y low. Because B-c << B-loc and the short-range spin-spin interaction is un changed, the nuclear spin entropy was fully sustained across the sc transit ion. The relaxation in the sc state was slower at all temperatures without the coherence enhancement close to T-c. Nonzero nuclear polarization strong ly reduced the difference between the relaxation rates in the sc and normal states.