Preparation and characterisation of lanthanum doped BaTiO 3 nanosize polycrystals by sol–gel processing

Abstract

Sol–gel processing has been refined to prepare lanthanum doped barium titanate nanosize polycrystal powders, La_xBa_1-xTiO₃ (x=0.05, 0.15, 0.20, 0.25), in the presence of Ba(OAc)₂, La(OAc)₃, and Ti(OⁿBu)₄ as starting materials with 0.7 mol L^-1 total concentration of precursor. The sol was obtained by cosolubilised hydrolysis of starting materials using HOAc as medium and catalysis with pH∼3.8. The wet gel was acquired by concentrating and aging at room temperature. The wet gel to dry gel conversion was carried out at 50°C for ∼24 h. First the dry gel was characterised by differential thermal analysis–thermal gravimetry (DTA–TG) and then it was calcined at various temperatures (600, 700, 800, 900°C) to prepare the nanocrystals. The final synthesised polycrystals were characterised by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, and scanning electron microscopy.