Advancing piezoelectric properties of barium titanate ceramic through AC + DC field poling over Curie temperature

The significance of increased domain nucleation sites from smaller grain size (GS) of barium titanate (BT) ceramics on piezoelectric properties was analyzed for different types of poling, including conventional direct current (DC) poling, modified DC poling, and alternating current (AC) plus DC poling, conducted at different poling temperature. The AC plus DC poling conducted at 1.5 ℃ above the Curie temperature showed the highest piezoelectric constant (d 33) of 528 pC/N, with an average domain size of 100 nm observed after poling. The d 33 improvement was attributed to smaller domain size formation from field-induced phase transitions and homogenous distribution of point defects achieved by the AC field. Comparative analysis with larger grain BT ceramics under AC plus DC poling suggests that defects and volume fraction of grain boundaries in BT ceramics could have an effect on domain sizes.