Preparation of nanocrystalline lithium niobate powders at low temperature

Abstract A facile route to prepare lithium niobate (LiNbO 3 ) powders was proposed by an alternative solid‐state method. Stoichiometric Li 2 C 2 O 4 and ammonium niobium oxalate were mixed with small amounts of water and then dried at room temperature. It was demonstrated that Li[NbO(C 2 O 4 ) 2 ]· n H 2 O intermediate was produced by an ion‐exchange reaction. Pure LiNbO 3 powders were successfully synthesized by heating the intermediate at 500, 600 and 700 °C for 3 h. X‐ray diffraction (XRD), scanning electron microscopy (SEM), Fourier‐transform infrared (FTIR) spectroscopy, UV‐Vis diffuse reflectance (UV‐Vis) spectroscopy and thermogravimetric (TG) analysis were used to characterize the precursor compound and as‐prepared samples. XRD results reveal that all the products are identified as hexagonal structure with high relative crystallinity (>87%). The particle size is found to be about 40 nm for the mixture calcined at 500 °C according to XRD data, which is in good agreement with SEM data. The as‐prepared LiNbO 3 powders by this method are high quality according to FTIR spectra. (Li 0.996 Nb 0.005 )Nb 0.999 O 3 phase was formed when the calcination temperature was raised to 800 °C. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)