Structural and luminescence investigation on gadolinium gallium garnet nanocrystalline powders prepared by solution combustion synthesis

Abstract

Nanocrystalline powders of undoped and lanthanide (Pr 3+ , Tm 3+ )-doped gadolinium gallium garnet, Gd 3 Ga 5 O 12 (GGG), were prepared by propellant synthesis and studied by x-ray powder diffraction (XRD), electron diffraction (ED), high-resolution electron microscopy (HREM) and luminescence spectroscopy. The x-ray diffraction patterns of the GGG samples were analysed using the Rietveld method. The Rietveld refinement reveals the existence of two garnet-type phases: both are cubic (space group I a 3d) with a slightly different lattice parameter and probably a slightly different composition. Electron diffraction and electron microscopy measurements confirm the x-ray diffraction results. EDX measurements for lanthanide-doped samples show that stable solid solutions with composition Gd 3-x Ln x Ga 5 O 12 , x 0.3 (Ln = Pr; Tm) have been obtained. The luminescence properties of the Tm 3+ -doped nanocrystalline GGG samples were measured and analysed.