Barium iron vanadate glass, e.g.,
(in mol %), and its analogs show high electrical conductivity amounting to the order of 10-1
[1-4]. This is brought about by the isothermal annealing for only several ten minutes at a given temperature higher than its glass transition temperature or crystallization temperature. The electrical conductivity are tunable from the order of 10-6
by changing the condition of isothermal annealing. The marked increase in the electrical conductivity was attributed to the structural relaxation of the “3D
-network” which was preferable for the small polaron hopping from VIV
. Substitution of CuI
) and CuII
) for FeIII
) caused a further increase in the electrical conductivity [2-4], e.g
glass annealed at 450 °C for 30 min showed an increase of the electrical conductivity
, which was one order of magnitude larger than that of non-substituted vanadate glass (3.4×10–2
In this study, we investigated the substitutional effect of SnIV (4d10) and SnII (5s2) on the structure and the electrical conductivity of barium iron vanadate glass annealed at 500℃ for 0 - 300 min. The electrical conductivity of the annealed vanadate glass containing SnO (20BaO‧5Fe2O3‧5SnO‧70V2O5) was three orders of magnitude smaller than that of the conventional conductive vanadate glass (20BaO‧ 10Fe2O3‧70V2O5). Figure shows RT-Mössbauer spectrum of conductive vanadate glasses annealed at 500℃ for 60 min. The quadrupole splitting (Δ) of FeIII increase from 0.57 to 0.66 mms−1 as the composition of SnO increase, which reflected a decreased symmetry or an increased distortion of FeO4 and VO4tetrahedra [2-4]. Such a local distortion of the network should decrease the carrier mobility, and be contributed to the lower conductivity.
1) Fukuda, A. Ikeda and T. Nishida, Solid State Phenom., 90/91, 215-220 (2003).
2) Nishida, S. Kubuki, K. Matsuda and Y. Otsuka, Croat. Chem. Acta 88(4) 427-435 (2015).
3) K. Matsuda, S. Kubuki and T. Nishida, AIP Conf. Proc. (msms2014), 1622, 3-7 (2014).
4) T. Nishida, Y. Izutsu, M. Fujimura, K. Osouda, Y. Otsuka, S. Kubuki and N. Oka, Pure and Appl. Chem. (2017). [DOI: https://doi.org/10.1515/pac-2016-0916]