The charged defective structure in Bi1−xLaxFeO3 and La-10% and 2%Mg co-doped

BiFeO3 thin films as well as their relations to leakage and dielectric relaxation

behaviour were investigated. Through temperature-dependent conductivity and Xray

photo-electron spectroscopic analyses, it was demonstrated that La-doping

suppressed, but Mg-doping increased, the concentration of both oxygen vacancies

and Fe2+ ions. Correspondingly, the leakage mechanism evolves from grain

boundary and space charge limited conduction of Bi1−xLaxFeO3 (x = 0.2 and 0.1) to

Poole–Frenkel emission of %Mg co-doped BiFeO3 and BiFeO3. Although the

dielectric relaxation originates from the migration of oxygen vacancies, the

formation of defect complexes between the acceptors and oxygen vacancies was

responsible for the increased activation energy of the %Mg co-doped BiFeO3 film.

Modulated Charged Defects and Conduction Behaviour in Doped BiFeO3 Thin

Films. Y.Wang, J.Wang: Journal of Physics D, 2009, 42[16], 162001