Abstract
Antiferroelectrics (AFE) can exhibit a “shape memory function controllable by electric field”, with huge isotropic volumetric expansion (0.26%) associated with the AFE to Ferroelectric (FE) phase transformation. Small inverse electric field application can realize the original AFE phase. The response speed is quick (2.5 ms). In the Pb0.99Nb0.02[(Zr0.6Sn0.4)1-yTiy]0.98O3 (PNZST) system, the shape memory function is observed in the intermediate range between high temperature AFE and low temperature FE, or low Ti-concentration AFE and high Ti-concentration FE in the composition. In the AFE multilayer actuators (MLAs), the crack is initiated in the center of a pair of internal electrodes under cyclic electric field, rather than the edge area of the internal electrodes in normal piezoelectric MLAs. The two-sublattice polarization coupling model is proposed to explain: (1) isotropic volume expansion during the AFE-FE transformation; and (2) piezoelectric anisotropy. We introduce latching relays and mechanical clampers as possible unique applications of shape memory ceramics.
Highlights
Antiferroelectrics (AFE) can exhibit a “shape memory function controllable by electric field”, with huge isotropic volumetric expansion (0.26%) associated with the AFE to Ferroelectric (FE) phase transformation
The shape memory ceramics were applied to devices such as latching relays and mechanical mechanical clampers, where the ceramic is capable of maintaining the excited ON state even when electricity is not applied continuously to it
Antiferroelectrics (AFE) can exhibit a shape memory function controllable by electric field, with huge isotropic volumetric expansion (0.26%) associated with the AFE to Ferroelectric (FE) phase transformation
Summary
Development of solid state actuators aimed at replacing conventional electromagnetic motors has been remarkable in the following three areas: precision positioning, vibration suppression and miniature motors. An AFE exhibits an electric field-induced phase transition to a FE state above a critical field Et, accompanied by a hysteresis above Et. Reducing the field down to zero, the remanent polarization is not observed, providing a so-called “double hysteresis” curve in total. Ceramics “shape memory” has been reported for certain ferroelectricity-related transitions, namely paraelectric–ferroelectric [11] and antiferroelectric (AFE)–ferroelectric (FE) transitions [12,13] The former thermally-induced transition revealed a shape-recovery phenomenon similar to zirconia ceramics. On the contrary, the latter is related to an electric field-induced transition, and exhibits large displacement (0.4%) with a “digital” characteristic or a shape memory function, which is in contrast to the essentially “analogue” nature of conventional piezoelectric and electrostrictive strains with 0.1% in magnitude (Figure 1b).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
