Shaped crystal growth and scintillating properties of Yb : (Gd, Lu)(3)Ga5O12 solid solutions

摘要

Shaped single crystals of (LuxGd1-x)(3)Ga5O12 (0.0 less than or equal to x less than or equal to 1.0) and (Yb0.05LuxGd0.95-x)(3)Ga5O12 (0.0 less than or equal to x less than or equal to 0.9) were grown by the modified micro-pulling-down method. Continuous solid solutions with garnet structure and a linear compositional dependency of crystal lattice parameter in the system Yb:(Gd, Lu)(3)Ga5O12 are formed. Measured optical absorption spectra of the samples show 4f-4f transitions related to Gd3+ ion at 275 and 310 nm, and also an onset of charge transfer transitions from oxygen ligands to Gd3+ or Yb3+ cations below 240 nm. A complete absence of Yb3+ charge transfer luminescence under X-ray excitation in any of the investigated samples was explained by the overlapping of charge transfer absorption of Yb3+ by that of Gd3+ ions. For specific composition of Lu1.5Gd1.5Ga5O12 an intense defect-host lattice-related emission, which achieve of about 40% integrated intensity compared with Bi4Ge3O12, was found. (C) 2004 Elsevier Ltd. All rights reserved.