beta-detected NMR of Li-8 in the normal state of 2H-NbSe2

beta-NMR of isolated Li-8 has been investigated in the normal state of 2H-NbSe2. In a high magnetic field of 3 T a single resonance is observed with a Gaussian line width of 3.5 kHz. The line shape varies weakly as function of magnetic field and temperature but has a strong orientation dependence. The nuclear electric quadrupole splitting is unresolved implying that the electric field gradients are 10-100 times smaller than in other non-cubic crystals. The nuclear spin relaxation rate is also anomalously small but varies linearly with temperature as expected for Korringa relaxation in a metal. These results suggest that Li adopts an interstitial position between the weakly coupled NbSe2 layers and away from the conduction band. (c) 2005 Elsevier B.V. All rights reserved