NUCLEAR-MAGNETIC-RESONANCE AND ELECTRICAL-CONDUCTIVITY IN SINGLE-CRYSTALLINE PARATELLURITE

Te-125 nuclear spin relaxation (NSR) and electrical conducvitiy measur ements were performed on single-crystalline paratellurite (alpha-TeO2) between room temperature and the melting point (1007K) at various oxy gen partial pressures. A defect model is developed which fits the expe rimental data. The model involves ionic oxgyen interstitials (O ''(i)) , doubly charged oxygen vacancies (V ''(o)) and charge-compensating el ectron holes (h(.)). The pressure dependence suggests that the NSR rat e is induced by the motion of V ''(o) while the conductivity is due to diffusion of h(.). Further, the chemical diffusion coefficient is sho wn to be caused by ambipolar diffusion of O ''(i) and h(.).