Defects and Leakage Current in PbTiO3 Single Crystals

Single crystals of PbTiO3 (PT) were grown by a self flux method, and effects of lattice defects on the leakage current properties were investigated. While PT crystals annealed in air at 700 oC showed a leakage current density of the order of 10-5 A/cm2, annealing under a high oxygen partial pressure of 35 MPa increased leakage current density to 10-4 A/cm2. The increase in leakage current by the oxidation treatment provides direct evidence that electron hole is a detrimental carrier for the leakage current property of PT at room temperature. The vacancies of Pb are suggested to act as an electron acceptor for generating electron holes.