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Correlation between size and phase structure of crystalline BaTiO3 particles synthesized by sol-gel method

In this work, we studied the correlation between size and phase structure of BaTiO3 (BTO) particles synthesized using a sol-gel method. The calcination temperature was varied from 600 to 1100 °C with an increment of 100 °C. On the basis of scanning electron microscopy (SEM) and X-ray diffraction (XRD) results, it was found that the crystallite and particle sizes of BTO increased as the calcination temperature increased. The average particle size of BTO was close to its crystallite size at low calcination temperatures. However, a large difference between crystallite and particles sizes was evident at high calcination temperatures, indicating the formation of several crystallites in an individual particle. According to the XRD and Raman spectroscopy analyses, the BTO particles evolved from a cubic to a tetragonal structure at a calcination temperature of 800 °C. The cubic-to-tetragonal phase transformation of sol-gel derived BTO particles occurred at a critical crystallite size of about 30 nm and a particle size of about 100 nm. We anticipate that the obtained results here can be a useful guideline and reference for the preparation of nanocrystalline BTO particles with a desirable size and phase structure.