Electronic conduction in : the dependence on the oxygen stoichiometry

Abstract

We report a systematic study of the electronic transport properties of the metallic perovskite oxide as a function of the oxygen stoichiometry . The electrical resistivity, magnetoresistance, susceptibility, Hall effect and thermopower have been studied. All of the transport coefficients are dependent on the value of . The resistivity increases almost exponentially as increases. We relate this increase in to the creation of with square-planar coordination. We find that there is a distinct -contribution to the resistivity over the whole temperature range. The thermopower is negative, as expected for systems with electrons as the carrier, but the Hall coefficient is positive. We have given a qualitative and quantitative explanation for the different quantities observed and their systematic variation with the stoichiometry .