An EXAFS study of the local structure of rare-earth luminescence centres in the 3CaO-Ga2O3-3GeO(2) glass

The extended X-ray absorption fine structure (EXAFS) at L-3 edges of rare-earth atoms in glass of 3CaO-Ga2O3-3GeO(2) (or Ca3Ga2-Ge3O12) composition doped with Eu, Ho (0.7 wt.%) and Er (1.46 wt.%) has been investigated. The obtained structural parameters of the Eu, Ho and Er first (oxygen) coordination shell have shown that the local neighbourhood is independent on the kind of rare-earth ions' impurity and, taking into account structural disorder, is similar to that present in pure oxide systems. Short-range structures around the considered luminescence centres are discussed and compared with relevant literature data. (c) 2007 Elsevier B.V. All rights reserved.