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Low Temperature Ionic Conductivity of an Acceptor‐Doped Perovskite: II. Impedance of Single‐Crystal BaTiO 3
Author(s) -
Maier Russell A.,
Randall Clive A.
Publication year - 2016
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14347
Subject(s) - acceptor , activation energy , materials science , conductivity , ionic conductivity , perovskite (structure) , doping , dopant , dielectric spectroscopy , vacancy defect , atmospheric temperature range , single crystal , dielectric , permittivity , ferroelectricity , analytical chemistry (journal) , chemistry , condensed matter physics , crystallography , electrolyte , thermodynamics , optoelectronics , electrode , physics , chromatography , electrochemistry
Low temperature conductivity mechanisms were identified in acceptor‐doped BaTiO 3 single crystals equilibrated and quenched from high temperature under different oxygen partial pressures. A range of acceptor ionization states were quenched into samples doped with manganese or iron. Using an appropriate equivalent circuit to interpret impedance spectroscopy data, room temperature conductivity mechanisms in the single crystal samples were identified, and the permittivity/temperature dependence was also shown to be self‐consistent with the nature of a first‐order ferroelectric phase transition. The primary, low temperature, conduction mechanism in acceptor‐doped BaTiO 3 was determined to be dominated by the migration of oxygen vacancies. The activation energy for oxygen vacancy migration was experimentally determined to have a value of nearly 0.7 eV. This activation energy represents an intrinsic value for vacancy hopping and confirms our previous work that revealed minimal interaction between acceptor dopants and oxygen vacancies in BaTiO 3 in contrast to the well‐documented evidence of defect association in SrTiO 3 .