Preparation and characterization of LaNbO4 from amorphous precursors

Amorphous precursors of LaNbO4 have been prepared by coprecipitation and mechanical alloying. Powder characteristics before and after calcination were studied by thermogravimetric analysis, differential thermal analysis, Fourier transform-infrared spectroscopy and X-ray diffraction, and the crystallographic changes during thermal treatment were documented by high-temperature X-ray diffraction. The tetragonal structure was stabilized at room temperature for the mechanically alloyed product; cells dimensions were determined from the X-ray diffraction patterns and volume change between monoclinic and tetragonal phase was evaluated and is discussed.