Electric field dependence of strain induced by electric field on piezoelectric ceramics

Electric field dependence of the strain characteristics on the (Pb, Ba, Sr)(Zr, Ti, Sn, Nb)O3 compositions were investigated. It was found that the measured strain (δ) increases with increasing applied DC electric field. The δ was larger than the strain of calculated value (δcal) from multiplying the piezoelectric constant (d31) by the applied DC electric field (E). The difference strain (δp) between δ and δcal increased with increasing applied DC field. On high DC electric field, the δp was saturated with compositions near the morphotropic phase boundary and the rhombohedral structure. We deduced that δ and δp were involved with the electric field dependence on rotation of domain which was measured by XRD analysis. These results indicated that the δp was caused by rotation of domain. The electric field dependence on the change of δ in the durability test, under repetitious DC electric field, was investigated. Higher applied DC electric field produced larger change of δcal and decreasing the δp. We found that the increase of δcal and the decrease of δp were caused by accelerating the polarization.