1. New Piezoelectric Oxide Materials P. Shiv Halasyamani (Univ
New Piezoelectric Oxide Materials P. Shiv Halasyamani (Univ. Houston), AC10
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New Piezoelectric oxides may be synthesized by utilizing cations susceptible to second-order Jahn-Teller (SOJT) distortions. These cations are d0 transition metals (Ti4+, Nb5+, W6+, etc.) and lone-pair cations (Se4+, Te4+, Sb3+, etc.).
Using this methodology, we have synthesized and characterized a variety of new piezoelectric oxides, including, Li2Ti(IO3)6, Na2Ti(IO3)6, and large single crystals of Na2TeW2O9.
The figure depicts the energy landscape with respect to inversion of the polarization in a IO3 polyhedron. The energy barrier to inversion is -8.5eV which is substantially larger than in ferroelectrics such as BaTiO3 (∼1.8 × 10-2 eV) and PbTiO3 (∼2.0 × 10-1 eV).
We have grown > cm size single crystals of Na2TeW2O9, a piezoelectric oxide material, through a top-seeded solution growth (TSSG) technique. A schematic of the furnace is shown to the right.