TRANSITION TEMPERATURE VARIATIONS IN SODIUM BARIUM NIOBATE AND RELATED COMPOSITIONS

Transition temperature, Tc, variations up to 33°C can be induced in the tungsten bronze ferroelectric NaBa2Nb5O15 by quenching single crystals from high temperatures. This probably accounts for the differences in the published values of Tc. Quenching is believed to cause disorder in the crystal lattice. To further test this hypothesis other ferroelectric tungsten bronze compositions as KxNa1-xBa2Nb5O15 and Na1.12Ba4.44Nb5O15(Tc = 535°C) with less ordering were studied. The results are consistent with this hypothesis. © 1969.