Low temperature conductivity mechanisms are identified in acceptor doped BaTiO3 single crystals equilibrated and quenched from high temperature under different oxygen partial pressures. A range of acceptor ionization states are quenched into samples doped with manganese or iron dopants. Impedance spectroscopy measurements are used to identify room temperature conductivity mechanisms in the single crystal samples, and permittivity temperature dependence are also shown to be self-consistent with the nature of the first order ferroelectric phase transition using an appropriate equivalent circuit to interpret the impedance data. The primary conduction mechanism is determined to be dominated by the migration of oxygen vacancies. The activation energy for oxygen vacancy migration is determined to have a value of nearly 0.7eV agreeing well with values found in the similar perovskite structure of SrTiO3.
Citation: Journal of the American Ceramic Society
Pub Type: Journals
oxygen vacancy, ionic conductivity, perovskite, impedance spectroscopy