Investigation of lanthanum substitution effects in yttrium aluminium garnet: importance of solid state NMR and EPR methods

In this study, yttrium aluminium garnet (YAG) specimens in which yttrium was partially substituted by lanthanum Y3-xLaxAl5O12 (YLaAG) were prepared by an aqueous sol-gel method. YLaAG samples were analyzed by X-ray diffraction (XRD), solid state nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) methods. The presence of Ce3+ ions as an impurity originating from starting material was determined, therefore, luminescence measurements of YLaAG samples were also recorded. It was demonstrated that luminescent properties are strongly dependent on the phase composition of synthesized species. The XRD analysis results showed that only low substitution of yttrium by lanthanum is possible in Y3-xLaxAl5O12 without destroying garnet crystal structure. It was also demonstrated, that solid state NMR and EPR methods are indispensable tools for the explanation of processes and properties observed in the newly synthesized Y3-xLaxAl5O12 compounds.

Automated summary

Yttrium aluminium garnet (YAG) specimens with partial substitution of yttrium by lanthanum Y3-xLaxAl5O12 (YLaAG) were prepared using an aqueous sol-gel method, and analyzed by various techniques. Luminescent properties were found to be closely related to the phase composition, and solid state NMR and EPR methods were essential for explaining the processes and properties observed in the newly synthesized Y3-xLaxAl5O12 compounds.