Synthesis and evolution of crystalline garnet phases in Y₃Sc_5–xGa_xO₁₂

Abstract

Mixed-metal oxides with the composition Y₃Sc _x Ga_{5− x} O₁₂ (x = 2.0, 2.1, 2.2, 2.25, 2.3, 2.4, 2.5, and 3.0) have been prepared by an aqueous sol–gel method. The effects of scandium substitution on the garnet phase formation were studied by IR spectroscopy and X-ray powder diffraction (XRD). The XRD data indicate that single-phase Y₃Sc _x Ga_{5− x} O₁₂ ceramic samples were obtained for x = 2.0, 2.1, 2.2, 2.25, 2.3, and 2.4. The results also show that the formation of Y₃Sc _x Ga_{5− x} O₁₂ garnets depends on the molar ratio of scandium and gallium in the investigated composition, and consequently on the mean cationic radius at the Al³⁺ sites. The variation of lattice parameters for the Y₃Sc _x Ga_{5− x} O₁₂ phases with different x is reported.

Acknowledgements

EG is thankful for a Lithuanian Science and Studies Foundation Scholarship administered through the Ministry of Education, Youth and Sport of the Czech Republic. The authors from Vilnius University gratefully acknowledge the financial support from the Lithuanian State Science and Studies Foundation under project MODELITA (No. C-03048). JP gratefully acknowledges the financial support by the GACR 203/04/0296. The authors thank Dr Hao Shen (Institute of New Materials, Saarbruecken, Germany) for experimental support.