Preparation and characterization of highly (222)-oriented bismuth magnesium niobate thin film by sol-gel method

• Highly (222)-oriented BMN thin film was prepared by sol-gel technique.
• A growth mechanism of self-assembly process of(222)-oriented BMN film was proposed.
• Process-orientation-property relationship in (222)-oriented BMN film was discussed.

Highly (222)-oriented Bi1.5MgNb1.5O7 thin films have successfully been prepared on SiO2/HR-Si substrates by sol-gel method with rapid thermal annealing (RTA). The films were characterized using X-ray diffraction, high-resolution transmission electron microscope and atomic force microscope. The results revealed that the thus-derived films possessed a cubic pyrochlore structure with regular and smooth surface, and exhibited superior dielectric constant of about 170. The growth of (222)-oriented BMN thin film can be explained as a self-assembly process, and the mechanism of self-assembly process was elaborated. The formation of the large dielectric constant of the film was mainly assigned to the highly (222) orientation and large in-plane tensile strain.