Nonstoichiometry in Acceptor-doped BaPbO_3

The defect chemistry of BaPbO_3 was studied by the measurement of the equilibrium elec- trical conductivity as a function of oxygen pressure (10~(-12)-10~5 Pa).The major defects and their charge-compensating defects in undoped and acceptor-doped BaPbO_3 were present.The influence of impurities concentrations on equilibrium electrical conductivity and both infiexions of the change of major defects in high and low oxygen-activity regions were discussed.At highly oxygen activity the major defects are lead vacancies and their compensating holes.With the decreasing in oxygen activity, the major defects will change from intrinsic disorder into extrinsic disorder and the acceptor impurities become the major source of defects.At lower oxygen activity the oxygen vacancies become compensat- ing defects instead of the holes,and the reducing reaction becomes the major source of compensating defects.Both inflexions in high and low oxygen-activity regions move to higher oxygen activity with the increasing of acceptor concentrations.