High electrostrictive coefficient Q33 in lead-free Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 piezoelectric ceramics

In this study, the electrostrictive effect in Ba(Zr0.2Ti0.8)O-3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT, x = 0.4, 0.5, and 0.6) ceramics was investigated to gain understanding of their high piezoelectric activity. The electrostrictive coefficient Q(33) of the BZT-xBCT ceramics was observed to be around 0.04 m(4)/C-2, twice that reported for Pb(Zr,Ti)O-3-based ceramics. The Q(33) was found to be quite stable with respect to temperature and composition for the BZT-xBCT ceramics. The addition of Fe3+ dopant to the ceramics greatly decreased their Curie temperature without affecting their Q(33), which remained 0.04 m(4)/C-2. Moreover, a high and hysteresis-free electric-field-induced strain was obtained for 2 at. % Fe-doped BZT-0.5BCT ceramics at room temperature, caused by their high Q(33) coefficient and lower-than-room-temperature Curie temperature. The small-signal M-33 coefficient of 2 at. % Fe-doped BZT-0.5BCT ceramics was found to be 1.5 x 10(-16) m(2)/V-2 (0.32 x 10(-16) m(2)/V-2 for undoped counterpart). These results indicate that 2 at. % Fe-doped BZT-0.5BCT ceramics have great potential as alternatives for hard Pb(Zr,Ti)O-3 ceramics in actuator applications, where reproducible and non-hysteretic deformation responses are required. (C) 2014 AIP Publishing LLC.