Vibrational and luminescent properties of polycrystalline zircon: Effect of structural and impurity defects

Highlights: • Single-phase high-purity ZrSiO₄ was synthesized by sol-gel method. • Instability of structural defects during high-temperature annealing was observed. • Raman spectroscopy indicated a high degree of perfection of crystalline fraction. • Defects observed are typical of natural zircon with low self-radiation damage. Zircon was synthesized by the sol-gel route and subjected to sequential heat treatment. X-ray powder diffraction showed that single-phase zircon was obtained. The impurity content and microstructure of the obtained ceramic were studied by the mass spectrometry and scanning electron microscopy. The contents of Hf ~0.8wt% and Al ~0.2wt% are prevailing, while the presence of other impurity elements does not exceed 0.06wt%. The photo- and cathodoluminescence data indicate the presence of structural and impurity defects. The instability of structural defects during high-temperature annealing was observed. The average value FWHM of the Raman B_1g(4) band of asymmetric stretching vibrations of SiO₄ tetrahedra lies in the range 2.55–3.15cm^-1, which slightly exceeds the minimum value ~1.8–2.0 cm^-1 in the spectra of perfect single crystals. The zircon synthesized can be used as a reference sample for spectroscopic studies in mineralogy.