Study of electron paramagnetic resonance in vanadyl doped tungsten lithium borate glasses

Anshu, S Rani, A Agarwal, S Sanghi, N Kishore, V Seth
2008 Indian Journal of Pure & Applied Physics   unpublished
Glasses with composition xWO 3 .(30-x)Li 2 O.70B 2 O 3 containing 2 mol % V 2 O 5 have been prepared over the range 0≤ x≤ 15 (x is in mol % and in steps of 2.5). The electron paramagnetic resonance (EPR) spectra of VO 2+ in these glasses have been recorded on X-band (v ≈ 9.14 GHz) at room temperature (RT). The spin Hamiltonian parameters, dipolar hyperfine coupling parameter, P and Fermi contact interaction parameter, K, have been calculated. It has been found that V 4+ ions in these glasses
more » ... in these glasses exist as VO 2+ in octahedral coordination with a tetragonal distortion. Results suggest that the tetragonality of the V 4+ O 6 complex changes with change in WO 3 :Li 2 O ratio. Values of theoretical optical basicity have also been calculated. 1 Introduction Electron paramagnetic resonance (EPR) spectroscopy is a sensitive technique for the study of transition metal (TM) ions in solids. It provides information concerning the valence state of TM ions, local environment and the nature of interactions between them. The transition metal ions can be used to probe the glass structure because their outer d electron orbital functions have rather broad radial distributions and their responses to surrounding cations are very sensitive 1. Vanadyl ion (VO 2+) has been used as a spectroscopic probe for characterization of glasses because their EPR spectra are rich in hyperfine structure due to 51 V nucleus and is easily observable at room temperature 2,3 .