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 c alculations were used to estimate the influence of sample shape and el ectrode geometry on-the measured values. Between 19 and 353 K samples, which were quenched under reducing conditions, show an impurity scatt ering 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 conjuncti on with measurements of the mass difference before and after reoxidati on, the oxygen deficiency and the oxygen vacancy concentration could b e 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 fir st time. In this temperature range the mobility does not depend on car rier concentration, but shows a T--1.5 dependence.