HALL-MOBILITY OF UNDOPED N-TYPE CONDUCTING STRONTIUM-TITANATE SINGLE-CRYSTALS BETWEEN 19-K AND 1373-K

The Hall mobility of undoped n-type conducting SrTiO3 single crystals was investigated in a temperature range between 19 and 1373 K. Field calculations were used to estimate the influence of sample shape and electrode geometry on-the measured values. Between 19 and 353 K samples, which were quenched under reducing conditions, show an impurity scattering behavior at low temperature and high carrier concentrations and a phonon scattering mechanism at room temperature. In this temperature region, no carrier-density-dependent mobility was found. In conjunction with measurements of the mass difference before and after reoxidation, the oxygen deficiency and the oxygen vacancy concentration could be determined. The oxygen vacancies proved to be singly ionized. Above 873 K, Hall mobility and carrier concentration had been determined as a function of both oxygen partial pressure and temperature for the first time. In this temperature range the mobility does not depend on carrier concentration, but shows a T--1.5 dependence.