Electron Paramagnetic Resonance of Vanadium-Doped SbPO4 – GeO2 Glasses

Reference	Presenter	Authors (Institution)	Abstract
10-036	Claudio Jose Magon	Magon, C.J.(Universidade de São Paulo); Donoso, J.P.(Universidade de São Paulo); Silva, I.D.(Universidade de São Paulo); Chiesa, M.(University of Turin); Morra, E.(University of Turin); Montesso, M.(Universidade Estadual Paulista); Manzani, D.(Universidade Estadual de Londrina); Nalin, M.(UNESP Araraquara);	Antimony based glasses have been increasingly studied due to their optical properties while the germanate based glasses receive much attention due to their high RE solubility, chemical durability and mechanical resistance making them an attractive material for infrared optical fiber applications [1]. This work reports the study of the local environment of vanadium ions in SbPO4- GeO2 glasses doped with 0.1mol% of V2O5 using EPR techniques [2-4]. The X- and Q band EPR spectra shows well resolved structure similar to those reported for vanadium-doped glasses, typical of VO2+ ions in axially distorted sites. The hyperfine structure resulted from the dipole-dipole interaction between the magnetic moment of the 51V nuclei (nuclear spin I = 7/2) and the electronic moment of the paramagnetic V4+ ion (3d1 electronic configuration, spin S = ½). Numerical simulations were performed and reveal the presence of two magnetically distinct (VO)2+ sites in the samples treated at 470 oC and 500 oC. X- and Q-Band pulsed EPR HYSCORE experiments were performed in the sample treated at 500 oC and show a distribution in the magnitude of hyperfine interactions between (VO)2+ ions and 31P nuclei. The hyperfine parameters aiso and Tii were obtained from numerical simulations of the HYSCORE spectra. From these parameters, the spin population transferred to the P 3s orbital and the maximum distance between (VO)2+ ions and 31P nuclei were estimated. Financial support from CeRTEV, Center for Research, Technology, and Education on Vitrous Materials (FAPESP 2013/07793-6) and CAPES are acknowledged. I.D.A. Silva acknowledges the financial support from the USP-Santander program (Edital USP-PRPG 04/2016). 1 : M. Nalin, et al. J. of Non-Cryst. Solids. 284 (2001) 110-116. 2: C.J. Magon et.al., J. Magn. Reson. 222, p. 26-33, 2012 3: B.K. Harikamalasree et.al., J. Non-Cryst. Solids 477, p. 12-20, 2017 4: J.R. Pilbrow. Transition Ion Electron Paramagnetic Resonance. Claredon Press, Oxford, 1990
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