Temperature Dependence of Strain Induced by Electric Field in Piezoelectric Ceramics

Abstract

The temperature dependence of piezoelectric constant (d31) and the strain characteristics of the (Pb0.845Ba0.105Sr0.05) ((ZrxTi1-x)0.95Sn0.045Nb0.005)O3 series (x=0.49, 0.52, 0.55), in which the grain size was controlled by hot-pressing (HP), were investigated between -196 and 90°C. The piezoelectric constant (d31) was measured using an impedance analyzer (YHP4192A). The strain characteristics were measured by applying DC electric field (1.0kV/mm) and the durability under repetitious DC electric field (1.0kV/mm, 1Hz). The results showed that the piezoelectric constant (d31) and the actually found strain (δ) under DC electric field increase with increasing temperature. Between -196 and 90°C, the actually found strain (δ) was larger than calculated value (δcal), obtained by multiplying the d31 with DC electric field. This difference (δ-δcal) was caused by the strain (δp) of domainial reorientation alone the intensity of electric field. It is found that the δp was nearly zero at -196°C (liquid nitrogen temperature), and increases with increasing temperature. Furthermore, it was clarified that the temperature dependence of δp varied with the composition and grain size. It is shown that the temperature dependence of δp is related to that of the binding force of domain (σb). In the durability test between -196 to 90°C, the δ became small after the test. The change of δ increased with increasing temperature. It is found that the decrease of δp led to that of δ. We found that the change of δp is dependent on the composition and grain size.