Random barrier height model for phase shifted conductivity in perovskites


A large dielectric permittivity peak which occurs at low frequency and high temperature in many perovskite crystals and ceramics, and an associated difference in dc and ac conductivity, is attributed to phase shifted conductivity resulting from mobility barriers of different heights. A model is developed which has intrinsic barriers, and higher and more widely spaced extrinsic barriers, and special cases are examined. Model predictions show good agreement with experimental results of Stumpe, Wagner, and Bäuerle for an SrTiO3 single crystal 1.02 mm thick. The additional peaks seen by them at higher temperature for a crystal 0.24 mm thick are qualitatively accounted for by adding a third set of still higher barriers with spacing equal to the crystal thickness.




V.H. Schmidt, G.F. Tuthill, C.-S. Tu, T.V. Schogoleva, and S.C. Meschia, “Random barrier height model for phase shifted conductivity in perovskites,” Ferroelectrics 199, 51-67 (1997).
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