Relaxor-normal ferroelectric transition in (1−x)Sr0.75Ba0.25Nb2O6–xNaNbO3 ceramics

Abstract

(1− x)Sr0.75Ba0.25Nb2O6– xNaNbO3 ( x = 0–0.8) ceramics were prepared by the traditional solid-state reaction method. The x = 0–0.4 ceramics preserve the tungsten bronze phase with a gradually unfilled–filled structure evolution accompanying a relaxor-normal ferroelectric transition. This transition process is accompanied by an increase in the maximum dielectric constant temperature or Curie temperature ( Tc), enhancement of room temperature ferroelectric and piezoelectric properties, and appearance of the stripe domain. On the other hand, ceramics with x > 0.4 consist of coexisting tungsten bronze and perovskite phases, for which Tc slightly fluctuates, and the ferroelectric and piezoelectric properties decrease with increasing x. This work provides a feasible way to manipulate the relaxor-normal ferroelectric transition and the electrical properties of the tungsten bronze family.