Tunability and ferroelectric relaxor properties of bismuth strontium titanate ceramics

A systemic study was performed on bismuth strontium titanate (Sr1-1.5xBixTiO3, 0.04 <= x <= 0.25) ceramics. Dielectric properties were measured from 83 to 373 K at different frequencies. A transformation from relaxor ferroelectrics to relaxor behavior was observed when x>0.10. Both diffuseness and relaxation degree increase as x rises. Tunability was found to increase with increasing x value until 0.07, and then decrease when Bi3+ content increases. Meanwhile, their figures of merit (defined as tunability/loss) shows a maximum at x=0.12. The change from relaxor ferroelectrics into relaxor behavior has a positive impact on the tunability of bismuth strontium titanate system. (C) 2007 American Institute of Physics.