Spectroscopic and dielectric investigations of tungsten ions doped zinc bismuth phosphate glass-ceramics

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• 作者：P. Srinivasa Rao ; S. Bala Murali Krishna ; S. Yusub ; P. Ramesh Babu ; Ch. Tirupataiah ; D. Krishna Rao ; ^{krdhanekula@yahoo.co.in}
• 关键词：Glass-ceramics ; XRD ; Raman spectra ; Optical absorption ; Dielectric properties
• 刊名：Journal of Molecular Structure
• 出版年：2013
• 出版时间：27 March, 2013
• 年：2013
• 卷：1036
• 期：Complete
• 页码：452-463
• 全文大小：2377 K

文摘

Pure and tungsten oxide doped ZnF₂Bi₂O₃P₂O₅ glass-ceramics are prepared by the melt quenching and heat treatment techniques. These samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS) and differential thermal analysis (DTA) techniques. The X-ray diffraction and the scanning electron microscopic studies have revealed the presence of BiPO₄, ¦Á-Zn₃(PO₄)₂, ¦Á-Zn(PO₃)₂, Zn₃(PO₄)₂, WOF₄, WOPO₄, ¦Ã-Bi₂WO₆, Bi₂W₂O₉, microcrystalline phases in these samples. FTIR and Raman studies exhibit bands due WO₄ and WO₆ units along with conventional phosphate groups. The optical absorption and electron spin resonance (ESR) spectra of present glass-ceramics indicate the co-existence of both W⁵⁺ and W⁶⁺ ions. The analysis of dielectric properties (dielectric constant, loss tan ¦Ä, a.c. conductivity) over a range of frequency and temperature suggests a gradual increase in semi conducting character with increase in the concentration of WO₃. The studies on dielectric breakdown strength indicated the lowest insulating strength for 5.0 mol % of WO₃ in the present samples.