span style="font-size:15.0pt;mso-bidi-font-size: 14.0pt;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; mso-bidi-font-family:Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US; mso-bidi-language:HI;mso-bidi-font-weight:bold" lang="EN-GB"Spectroscopic studies of Cusup2+/sup spin probe in sodium niobium based tellurite glasses/span

摘要

span style="font-size:9.0pt;mso-bidi-font-size: 12.0pt;font-family:" times="" new="" roman";mso-fareast-font-family:"times="" roman";="" mso-bidi-font-family:mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:hi"="" lang="EN-GB"Differential scanning calorimetry (DSC), electron spin resonance (ESR), Raman, infrared (IR) and optical absorption studies onb /b10Nasub2/subO-xNbsub2/subOsub5/sub-(89-x)TeOsub2/sub-1CuO glasses (where x =0, 5, 10, 15 and 20 mol%) containing Cusup2+/sup spin probe have been carried out. Glass transition temperature (i style="mso-bidi-font-style: normal"Tsubg/sub/i) and thermal stability of glass samples have been estimated from the DSC measurements and it has been found that both increase with increasing the Nbsub2/subOsub5/subi style="mso-bidi-font-style: normal" /icontenti style="mso-bidi-font-style:normal". /iFrom Raman and IR spectra, it is clear that present glass system consists of structural units of TeOsub3/sub (tp) and TeOsub4 /sub(tbp) and NbOsub6 /suboctahedra. Also, TeOsub4/sub units convert into TeOsub3/sub units with change in Nbsub2/subOsub5/sub content. The hyperfine splittings in the parallel features of ESR spectra of Cusup2+/sup are recorded for all compositions. ESR results show that span style="mso-bidi-font-weight:bold"gsub|| /sub gSubimg src='http://www.niscair.res.in/jinfo/line.gif' border=0/sub indicating that the span style="font-size:9.0pt;mso-bidi-font-size:12.0pt;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";mso-bidi-font-family:mangal;="" mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB"Cusup2+/sup span style="mso-bidi-font-weight:bold"ion is in tetragonal distorted octahedral site and its ground state is dsubx2- y2./sub There is considerable variation in Hamiltonian parameters for the different compositions. The observed optical absorption peak of Cusup2+/sup is found to be maximum at 780 nm for 10 mol% of Nbsub2/subOsub5/sub content.span style="mso-bidi-font-weight:bold" Bonding parameters and % bonding symmetry are calculated from both optical and ESR data changing with increasing Nbsub2/subOsub5/sub content. /span/span/span/span/span/span