Cerium Concentration and Sintering Atmosphere Influence on Y2.98–xCexAl5.02O12 Ceramic Phase Composition and Luminescence.

The phase composition and spectral-luminescent properties of samples of a luminescent ceramic, based on oxide compositions with makeup described by the general formula Y2.98–xCexAl5.02O12, where x = 0.05, 0.10, 0.20, 0.30, 0.45, and 0.60 formula units (f.un), were investigated. It is demonstrated that the phase composition of ceramic powders depends substantially on the cerium concentration and the calcination atmosphere. It was ascertained that the maximum concentration of cerium cations in the garnet lattice on calcination in air is equal to about 0.1 f.un, and in an argon and hydrogen atmosphere approximately 0.16 f.un The photoluminescence of ceramic samples excited by a 445 nm laser was investigated. It is shown that ceramic samples obtained by sintering in argon and hydrogen have a higher luminescence intensity compared to samples synthesized in vacuum. The possibility of shifting the wavelength of the maximum luminescence intensity from 546 to 570 nm by changing the cation composition and the sintering conditions of the ceramics was demonstrated. It is shown that oxidative annealing of ceramic samples adversely affects the intensity and position of luminescence maxima in highly cerium-doped oxide compositions Y2.98–xCexAl5.02O12. [ABSTRACT FROM AUTHOR]