Defect structure of rare earth aluminium garnets obtained by the glycothermal method

Rare earth aluminium garnets (REAG), Gd3Al5O12, Y3Al5O12 and Yb3Al5O12, having the particle size of 50–120, 30–50 and 30–50 nm, respectively, were prepared by glycothermal reaction. The unit cell parameters of REAGs were larger than the values reported in JCPDS cards. Rietveld analysis indicated the presence of Al vacancies in the 24d sites and oxygen vacancies in the 96h sites, and partial substitution of Al ions in the 16a sites with RE ions was also suggested. The occupancy of RE ions in 16a sites increased with the decrease in ionic size of the RE element.