Synthesis and characterization of nanocrystalline microwave dielectric LaAlO3 powder via sucrose method

Nanocrystalline lanthanum aluminate, LaAlO3, powder was synthesized by calcination of a precursor prepared through the evaporation of an aqueous solution consists of sucrose, polyvinyl alcohol, and stoichiometric amount of the desired Al and La nitrates. The phase evaluation (XRD) in conjunction with thermal analyses (DTA/TG) showed that a phase pure nanocrystalline lanthanum aluminate powder was obtained at temperatures between 600 and 700 °C. The synthesized powder had an average crystallite size in the range of ∼30 nm, as obtained from Reitveld analysis and transmission electron microscopy. The average particle size as determined by field emission scanning electron microscopy was smaller than 100 nm. The powder had a considerably high specific average surface area of ∼43 m2/g. According to the electrokinetic behavior of synthesized LaAlO3 power, it had point of zero charge at around 9.9.