Effect of oxygen vacancies on the dielectricity of Ga doped equimolar BiMnO3-BaTiO3 characterized by XPS analysis

Double oxide perovskites are fabricated by modifying the one by the other oxide through the ionic substitution process. However, the dielectric performance of typical such compounds is poor in general. It is because of oxygen vacancies concentration (V(sic)) increases due to the ionic substitution, which affects the conduction of charge carriers. In this work, Ga, which is known to be an element with high oxygen affinity, was chosen to dope the equimolar BiMnO3-BaTiO3 ceramic to decrease V(sic) during the mechanochemical synthesis. Consequently, the dielectric loss (at 200 degrees C with 1 kHz frequency) of BiMn(1-0.2)Ga0.2O3-BaTiO3 ceramic has been observed to decreased from 1.68 to 0.98 as compared to pristine specimen. Also, the resistivity was found to be increased from 1.0225 x 10(10) to 5.6452 x 10(12). The x-ray diffraction (XRD) scan showed the formation of single-phase perovskite with pseudo-cubic structure and a Ga doping associated lattice distortion. X-ray photoelectron spectroscopy (XPS) analysis explored the charge neutrality reaction of the doped ceramic and the interference effect of Ga in the Mn3+ to Mn2+ transition in this ceramic. The results are discussed in the context of the role of Ga to improve the dielectric behaviour and thus be suitable for storage device applications.

Automated summary

Doping with gallium, a high oxygen-affinity element, can reduce oxygen vacancies in double oxide perovskite ceramics, improving their dielectric performance and resistivity, potentially making them suitable for storage device applications.