Hyphenated thermal analysis for in situ study of (Bi,Nd)(4)Ti3O12 formation from aqueous solution-gel synthesis

Abstract

High-temperature X-ray diffraction, absorption-reflection infrared spectrometry and thermal analysis coupled on-line to mass spectrometry, were applied to citratoperoxo precursor gels and films of (Bi,Nd)(4)Ti3O12 (BNdT). A slow heating rate resulted in secondary phases (Bi2Ti2O7 and Bi2O3) while a high rate yielded phase pure layered perovskite BNdT. Comparison of the evolved gas profiles from the bulk gel and thin film, showed complete decomposition of the film at lower temperature than expected from thermogravimetric and evolved gas analysis of the bulk gel. Thermal methods adapted to thin films, therefore are crucial for understanding and controlling the oxide formation in the film.