Order–disorder phase transition in Ba(Zn1/3Ta2/3)O3

The order–disorder transition temperature in Ba(Zn1/3Ta2/3)O3 ceramics has been investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Samples were quenched into water after annealing at different temperatures ranging from 1550 to 1625 °C/15 h. XRD showed maximum ordering for samples annealed and quenched from 1600 °C accompanied by an order of magnitude increase in the size of ordered domains from that observed in as-sintered samples (20 nm). Although XRD revealed complete disorder for samples quenched from 1625 °C, 〈110〉 zone axis electron diffraction patterns revealed the presence of short range 1:1 and 1:2 ordering. XRD indicated that samples furnace cooled from 1625 °C were also disordered but could be re-ordered by annealing at 1500 °C.