Effects of Li/M (M = Al, Ga, In, and Er) co-doping on the electrical properties of BiFeO3–BaTiO3 ceramics

The defect structures and electrical properties of 0.75BiFeO3–0.25BaTiO3 ceramics have been modified using Li/M dopants (M = Al, Ga, In, and Er). The effects of Li/M dopants with various ionic radii and electronegativities on the crystal structure, dielectric properties, ferroelectricity, leakage, and insulation behaviors of the ceramics have been investigated. The doped ceramics displayed a typical perovskite structure with a dominant rhombohedral phase, but the impurities BaFe0.24Fe0.76O2.88 emerged and increased in concentration as doping content x increased. As x increased, the dielectric loss reduced and the ferroelectricity improved noticeably. At x = 6 mol%, leakage current and resistivity studies indicated that the ceramics showed enhanced insulating qualities, particularly high resistivity of ~ 1011 Ω cm was recorded in Li/Er-doped samples. The reduced oxygen vacancies are responsible for these results, which were evaluated by defect chemistry and validated by XPS analysis.