NMR-STUDIES OF ALKALI C-60 SUPERCONDUCTORS

The authors report C-13, Rb-87, K-39, and Cs-133 nuclear magnetic reso nance (NMR) measurements of lineshapes, Knight shifts, and spin-lattic e relaxation rates in the normal and superconducting states of M(3)C(6 0), where M(3) = Rb-3, K-3, Rb2K, RbK2, Rb2Cs, and RbCs2. Measurements are used as a guide to a new ammonia solvent synthesis technique. Tem perature dependence of the superconducting state electron spin suscept ibility is found to follow BCS weak coupling predictions. The issue of the Hebel-Slichter coherence peak is addressed.