Anomalous magnetic field dependence of the nuclear spin-lattice relaxation in liquid lithium-silicium alloys

Accurate measurements of the nuclear spin-lattice relaxation rate (1/T1) of 8Li nuclei in liquid LixSi1-x have been performed as a function of temperature (T) and magnetic field (B) for various compositions using the β-NMR method. The results show clearly that the magnetic field dependence of T1 follows a √B law around the x=0.5 composition. We interpret this as an indication for anomalous diffusion of electrons due to strong disorder. From the coefficient of the √B contribution to 1/T1 we derive that the partial Li s density of states at the Fermi level is about 1/10 of the total density of states at the Fermi level. This is the first observation of such a magnetic field dependence of 1/T1. (authors)