Preparation of La₂Zr₂O₇ by Sol—Gel Route

The La₂Zr₂O₇ phase was prepared from metal acetylacetonates by a sol—gel route without any intermediate phase formation. X‐ray peaks appeared at a temperature as low as 500°C at the positions expected for La₂Zr₂O₇, although they were broad. The crystal structure of La₂Zr₂O₇ was found to be of the fluorite type below 900°C and of thepyrochlore type above 1000°C. The substitution of a small amount of Eu for La was carried out to investigate the crystal structure from the viewpoint of fluorescence, and these results confirmed the formation of fluorite type La₂Zr₂O₇ below 900°C.