This work is supported by the Natural Sciences and Engineering Research Council of Canada. J.W.S. is partially supported by the Swiss National Science Foundation. Research at the University of Pennsylvania is supported by the National Science Foundation Materials Research Laboratory Program, DMR91-20668, and by the Department of Energy, DE-FC02-86ER45254.
Physical Review Letters
Muon spin rotation, Organic superconductors, Fullerenes, Muonium, Molecular bonds -- Analysis
Muon spin relaxation resulting from spin exchange scattering of endohedral muonium (μ+e-) with thermal electronic excitations has been observed in the fullerene superconductor Rb3C60. The temperature dependence of T1-1 shows a coherence peak just below Tc and can be fit to the conventional Hebel-Slichter theory for spin relaxation in a superconductor with a broadened BCS density of states. The average energy gap for electronic excitations, Δ/kB=53(4) K or 2Δ/ kBTc=3.6(3), is consistent with the BCS weak coupling limit.
Kiefl, R. F. and MacFarlane, W. A. and Chow, K. H. and Dunsiger, S. and Duty, T. L. and Johnston, T. M. S. and Schneider, J. W. and Sonier, J. and Brard, L. and Strongin, R. M. and Fischer, J. E. and Smith, A. B. (1993). Coherence peak and superconducting energy gap in Rb3C60 observed by muon spin relaxation. 70(25): 3987-3990.