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

Abstract

In this study, the electrostrictive effect in Ba(Zr0.2Ti0.8)O3-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 Q33 of the BZT-xBCT ceramics was observed to be around 0.04 m4/C2, twice that reported for Pb(Zr,Ti)O3-based ceramics. The Q33 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 Q33, which remained 0.04 m4/C2. 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 Q33 coefficient and lower-than-room-temperature Curie temperature. The small-signal M33 coefficient of 2 at. % Fe-doped BZT-0.5BCT ceramics was found to be 1.5 × 10−16 m2/V2 (0.32 × 10−16 m2/V2 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)O3 ceramics in actuator applications, where reproducible and non-hysteretic deformation responses are required.

Recent Progress on BaTiO3-Based Piezoelectric Ceramics for Actuator Applications

“…The strain for a 0.5BZT-0.5BCT ceramic can reach 0.05% in an electric field of 500 kV/mm [14], which is even larger than PZT-5H at the same electric field condition. Moreover, Bowman's group and other groups even reported a larger strain level at a near-MPB composition [59][60][61], which makes BZT-BCT ceramic a promising material for actuator application [62][63][64][65]. Besides piezoelectric coefficients, other parameters, such as maximum polarization, remnant polarization, dielectric permittivity etc.…”

Strain Mechanisms in Lead-Free Ferroelectrics for Actuators

“…The values of 33 = 0.04 m 4 /C 2 for BZT-BCT were reported and are relatively insensitive to variations of composition and temperature. 350 This suggests that is not the parameter determining differences in electromechanical properties. Therefore, as a first approximation, variations in the values are neglected.…”

“…342 Moreover, the O to T PPB is more elastic than the R to T PPB ( Figure 3.3 (c)), and displays similar elasticity as the convergence region. 318,341,349 Li et al 350 reported that the electrostrictive coefficients of BZT-BCT are ~ 0.04 m 4 /C 2 and remain relatively constant with composition and temperature. It was demonstrated that switching determines to a great extent small 323 and large 329 signal properties.…”

Electrostriction coefficient of ferroelectric materials from ab initio computation

“…For instance, it was suggested that the large piezoelectric coefficient of the lead-free ceramic system BZT-BCT 6,7 is originated from its large electrostriction coefficients. It is obvious that accurately obtaining electrostriction coefficient is a key step in such research.…”