Novel scalable synthesis of luminescent and magnetic single crystal garnets†

This letter reports a novel method for synthesizing RE₃Ga₅O₁₂, RE₃Al₅O₁₂, and RE₃Fe₅O₁₂ single-crystal garnets, where RE refers to rare earth elements, including Sc and Y. The garnets are crystallized upon cooling melts of heavy metal oxide glass-forming compositions containing the desired rare earth element. The novelty of this method lies in its ability to reproducibly obtain cubic single-crystal garnets doped with different rare earth elements using the same chemical route, with variations only in the melting temperature and cooling rate. A supersaturated composition in rare earth elements is melted at ∼1200 °C. During the cooling process, cubic crystals precipitate and grow from the supercooled liquid. A unique feature of this approach is that the resulting micrometric, almost monodispersed crystals are uniformly distributed within a residual glass matrix that can be easily etched away. A series of garnets were synthesized and characterized using several techniques. The main details for each family of garnets are presented herein.