Electromechanical instabilities

Many fundamental studies have been carried out to fully understand the nature of the positive effect of prestraining on the actuation performance of dielectric elastomers. The observed improvements have been mainly attributed to the enhancement of the actuator s stability. The main electromechanical instability in the dielectric elastomers is called the pull-in... 

The perovskite structure is, of course, of special significance in the electroceramics context since the ferroelectric perovskites are dominant in the ceramic capacitor, PTC thermistor and electromechanical transducer industries. The structure favours the existence of soft modes (low frequency phonons) as evidenced by its tendency to instability, for example the ferroelectric-paraelectric transition. Instability is evident in the case of the T23 compound which exhibits a tetragonal-orthorhombic transition in the region of 700 °C (the exact temperature depends on the oxygen content). Extensive twinning, very reminiscent of ferroelectric domain structures, is observed. 

---