  Microwave synthesis was optimized for preparing novel monoclinic Tin-doped
Barium Niobate ceramics (Ba1-xSnxNb2O6; x= 0.0, 0.01, 0.05, 0.1, 0.2, 0.3) BSN.
The intensity of monoclinic phase formation was observed to decrease on
increasing tin as dopant indicating decreased crystallinity. Strained
crystalline phase was observed in undoped sample that became severe on doping
tin. Monoclinic metal alloy Sn2O3 formation was confirmed on increasing tin
doping beyond 5%. Electronic configuration of tin (II) oxide supports the local
site-wise monoclinic disorder in crystal structure due to sterically active
lone pair. Such a disorder arranges increased number of degenerate energy
states and reduce effective energy gap between conduction band minimum and
valence band maximum. All BSN compositions were investigated for monoclinic
phase stabilization, ultra-violet absorption, dielectric response, raman modes
and type of carrier concentration along with hall resistivity. All measurements
possessed inflexion corresponding to 5 atomic % tin doping indicating
successful site substitution and estimated Sn2O3 metal formation beyond this.
The values of reducing optical energy band gap, transparency to visible
spectrum and hall resistivity indicated utility of these materials as a
substitute transparent conducting oxide (TCO) for well-known indium tin oxide
(ITO).
