Sol-Gel Synthesis and Characterization of LaAlO₃ Nanoparticles Using Gelatin as Organic Precursor

Abstract

LaAlO3 has gained attention in the last few years because of its favorable microwave dielectric properties, excellent lattice matching and a good matching for thermal expansion. Nanoparticles of LaAlO3 were produced by using gelatin as an organic precursor. The optimum temperature for the phase formation of the precursor sample is found out by TG/DTA analysis. The specific surface area of the powder was measured by the BET technique with nitrogen. X-ray diffraction (XRD) was used to determine the phases present in the calcined powders and to estimate particle size. The morphology of LaAlO3 powder was studied by transmission electron microscopy (TEM). Microwave dielectric properties were measured using a HP8722ET network analyzer. The results demonstrate that pure perovskite LaAlO3 powder formed at 800 °C for 2 h. And the crystallite size was in the range of 17-48 nm. The specimen sintered at 1450 °C for 8 h shows 97.4% of the theoretical density and gave the excellent microwave dielectric properties: εr=23.3 and Qf=32300 GHz.