Zr4+ and Ti4+ substitution in gallium garnets
Abstract
A study was undertaken of the formation of solid solutions with the garnet structure in the systems M3Ga5O12–M′O2–CaO (where M = Y3+, Nd3+ and M′= Zr4+, Ti4+). Synthesis of these compounds was performed by the traditional ceramic route as well as through hydroxide coprecipitation. Characterization was mainly carried out by X-ray diffraction, applying automatic structure-refining techniques. The Zr4+ and Ti4+ cations were shown to substitute for Ga3+ in octahedral sites, although there might be a degree of tetrahedral site distribution in the case of Ti4+, and the formation limits of the solid solutions for the systems were established. The application of concepts such as ionic size and charge was seen to be fundamental for understanding the behaviour of these garnets.