Accurate impedance measurements on differently sized samples of lead–zirconate–titanate (PbZr0.53Ti0.47O3, PZT) were analyzed using a CNLS procedure, resulting in the separation of the ionic and electronic conductivities at ~150 to 630C. At 603C, the electronic conductivity exhibited an approximately (PO2)1/4 dependence, while the ionic conductivity remained constant. Below the Curie transition temperature, the O non-stoichiometry became frozen-in and the conductivities were strongly dependent upon the sample history with respect to temperature sequence and ambient PO2. A tentative interpretation assumed defect association, i.e. the formation of neutral [VPb–VO··]x complexes, and electron-hole transfer between Pb sites and Pb vacancies to control the O ion conductivity in the tetragonal phase. Annealing PZT-based devices at about 600C under low O pressure (~1Pa oxygen) effectively decreased the low-temperature electronic conductivity by a factor of 100 and the ionic conductivity by a factor of 10 to 15 with respect to normal air processing.

Ionic and Electronic Conductivity in Lead Zirconate Titanate (PZT). B.A.Boukamp, M.T.N.Pham, D.H.A.Blank, H.J.M.Bouwmeester: Solid State Ionics, 2004, 170[3-4], 239-54