title: Formation of nanostructures in Eu3+ doped glass-ceramics: an XAS study.
abstract: We describe the results of x-ray absorption experiments carried out to deduce structural and chemical information in Eu(3+) doped, transparent, oxyfluoride glass and nanostructured glass-ceramic samples. The spectra were measured at the Pb and Eu-L(III) edges. The Eu environment in the glass samples is observed to be similar to that of EuF(3). Complementary x-ray diffraction experiments show that thermal annealing creates β-PbF(2) type nanocrystals. X-ray absorption indicates that Eu ions act as seeds in the nanocrystal formation. There is evidence of interstitial fluorine atoms around Eu ions as well as Eu dimers. X-ray absorption at the Pb-L(III) edge shows that after the thermal treatment most lead atoms form a PbO amorphous phase and that only 10% of the lead atoms remain available to form β-PbF(2) type nanocrystals. Both x-ray diffraction and absorption point to a high Eu content in the nanocrystals. Our study suggests new approaches to the oxyfluoride glass-ceramic synthesis in order to further improve their properties.
authors.affiliation: MALTA Consolider Team, ICMUV, Universidad de Valencia, Spain. Julio.Pellicer@uv.es
authors.forename: J
authors.initials: J
authors.lastname: Pellicer-Porres
authors.forename: A
authors.initials: A
authors.lastname: Segura
authors.forename: G
authors.initials: G
authors.lastname: Martínez-Criado
authors.forename: U R
authors.initials: UR
authors.lastname: Rodríguez-Mendoza
authors.forename: V
authors.initials: V
authors.lastname: Lavín
mesh_terms: D002516:Ceramics / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D005063:Europium / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D044367:Phase Transition; D056928:X-Ray Absorption Spectroscopy / Q000379:methods*
chemical_list: D005063:Europium