Samples were recovered in the form of sintered discs, which were later destructed into individual crystals. The morphology of doped crystals was studied by optical microscopy on an Eclipse 600pol (Nikon) and scanning electron microscopy (SEM) on a Supra 50 VP (LEO) equipped with INCA Energy 450 Xmax 80 (Oxford Instruments) microanalysis system. X-ray diffraction (XRD) patterns were collected using Rigaku D/MAX-2500V/PC X-ray diffractometer with rotation anode (CuKα1 radiation (λ = 0.15418 nm), scan step size of 0.02°).