Spectroscopic and <i>dc</i> conductivity studies of Cu²⁺ spin probe in 10Li₂O- <i style="">x</i>Nb₂O₅-(89-<i style="">x</i>)TeO₂ glass system

Abstract

<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="PlaceName" downloadurl="http://www.5iantlavalamp.com/"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="PlaceType" downloadurl="http://www.5iantlavalamp.com/"><smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place" downloadurl="http://www.5iantlavalamp.com/"> DSC,<b> </b>ESR, IR, Raman, optical absorption and <i>dc</i> conductivity studies on<b> </b>10Li₂O- <i style="">x</i>Nb₂O₅-(89-<i style="">x</i>) TeO₂ glasses containing Cu²⁺ spin probe have been carried out. Glass transition temperature (<i style="">T_g</i>) and thermal stability of glass samples are estimated from the DSC measurements and it has been found that both increase with increasing the Nb₂O₅ content. From IR and Raman spectra, it is clear that, the glass system consists of structural units of TeO₃ (tp), TeO₄(tbp) and NbO₆octahedra. TeO₄ units are found to be converted into TeO₃ units with increase in Nb₂O₅ content. From ESR spectra, it is found that the Cu²⁺ ion is in tetragonal distorted octahedral site with d_x²-y² as ground state_. The observed optical absorption peak of Cu²⁺ is found to be maximum at 800 nm for 10 mol % of Nb₂O₅ content. Bonding parameters and per cent bonding symmetry are calculated from both optical and ESR data and are found to change with increase in Nb₂O₅ content. The observed <i>dc</i> conductivity is found to be increasing with temperature and decreasing with increase in Nb₂O₅ content. </smarttagtype></smarttagtype></smarttagtype>