NUCLEAR-SPIN-LATTICE RELAXATION IN THALLIUM-CONTAINING CHALCOGENIDE GLASSES

NMR spin-lattice relaxation time (T1) measurements for the two naturally abundant isotopes of thallium have been performed in two thallium-containing chalcogenide glasses as a function of temperature and frequency. The results for T1 indicate that there are three regions of temperature dependence from 77 K to the glass-transition temperature. The relaxation in the high-temperature region is due to thallium-electron-thallium exchange. In the middle-temperature region, the relaxation is due to localized states, most likely the localized electronic states in the forbidden gap of amorphous semiconductors. The process responsible for the relaxation at low temperatures is probably the interaction of the thallium nuclei with disorder modes characteristic of amorphous materials. © 1979 The American Physical Society.