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Structural study of ionic: transition metal doped phosphate glasses for electrical and non-linear optical applications


Phosphate glasses can be easily prepared as binary metaphosphate glasses with a wide range of modifier oxides, which in turn create glass structural variations. Phosphate is also an excellent addition to ionic fluoride glasses, enhancing the glass formability by decreasing the tendency to crystallize. In fluoride phosphate glasses, fluoroaluminate octahedra are connected to phosphate tetrahedra through oxygen bonds and through the crosslinking capability of modifier cations (e.g. FPX system with [(100-X)[AlF3/MgF2/CaF2/SrF2]-XSr(PO3)2 with X=0 to 40]). Fluorophosphate glasses contain actually F-P linkages, as for example in the NAPFX series ((100-X)AlF3-XNaPO3 with X=100-40). While the FPX series has a higher F-content, the NAPFX glass series is a simpler system favored for structural analysis. Because of the phosphate content, both glasses can be doped with high levels of transition metal or rare earth metal ions. The fluoroaluminate to phosphate ratio determines the properties, including the optical positive partial dispersion of FP glasses, which is needed for many optical applications. In earlier experiments by D. Ehrt, phosphate ions in FPX glasses were replaced by sulphate ions or to study the glass forming region of sulphate-phosphate glasses. Stable sulphate containing glasses are not only interesting for their electrical and ion conducting properties but also sought after for the immobilization of radioactive nuclear waste containing sulphate compounds. Sulphate as complexing ligand for transition metal ions has also been studied by Ingram and Duffy et al. who found interesting transitional coordination environments of an eightfold coordination. The proposed research focuses on the characterization of ionic phosphate glasses containing transition metals. The impact of preparation conditions, through evaporation of F- and S- components is to be considered, as is the introduction of crucible material into the melt. Structural analysis by NMR, IR and Raman spectroscopy will be started during the project and, if necessary, later followed up at National Hellenic Research Foundation (NHRF Athens, Greece.) (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
MONCKE, DORIS; JIUSTI, JEANINI; SILVA, LAIS DANTAS; MARTINS RODRIGUES, ANA CANDIDA. Long-term stability of laser-induced defects in (fluoride-)phosphate glasses doped with W, Mo, Ta, Nb and Zr ions. Journal of Non-Crystalline Solids, v. 498, p. 401-414, . (13/07793-6, 17/02953-6)
TAGIARA, N. S.; CHATZIPANAGIS, I, K.; BRADTMUELLER, H.; RODRIGUES, A. C. M.; MONCKE, D.; KAMITSOS, I, E.. Network former mixing effects in alkali germanotellurite glasses: A vibrational spectroscopic study. Journal of Alloys and Compounds, v. 882, . (17/02953-6, 19/26399-3)
SANTOS, CAMILA PACHECO; MENDES SILVA, JULIA MELLER; DE OLIVEIRA, CAMILA MACHADO; JIUSTI, JEANINI; KLEGUES MONTEDO, OSCAR RUBEM; PETERSON, MICHAEL. Quartz quantification in porcelain stoneware tile formulations by differential scanning calorimetry. Thermochimica Acta, v. 705, . (13/07793-6, 17/02953-6)

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