Trapping of oxygen vacancies at crystallographic shear planes in acceptor-doped Pb-based ferroelectrics
Faculty of Sciences. Physics
Angewandte Chemie: international edition in English. - Weinheim
, p. 14787-14790
University of Antwerp
The defect chemistry of the ferroelectric material PbTiO3 after doping with Fe-III acceptor ions is reported. Using advanced transmission electron microscopy and powder X-ray and neutron diffraction, we demonstrate that even at concentrations as low as circa 1.7% (material composition approximately ABO(2.95)), the oxygen vacancies are trapped into extended planar defects, specifically crystallographic shear planes. We investigate the evolution of these defects upon doping and unravel their detailed atomic structure using the formalism of superspace crystallography, thus unveiling their role in nonstoichiometry in the Pb-based perovskites.