Forced electrostriction by constraining polarization switching enhances the electromechanical strain properties of incipient piezoceramics

Abstract

Recently developed lead-free incipient piezoceramics are promising candidates for off-resonance actuator applications due to their exceptionally large electromechanical strains. Their commercialization currently faces three critical challenges: the high driving electric field required for delivering the potentially large strains; large strain hysteresis, which is inappropriate for precision devices; and relatively high temperature dependencies. We propose that instead of utilizing incipient piezoelectric strains, harnessing the maximum possible electrostriction would provide a highly effective way to resolve all these challenges. This concept was experimentally demonstrated using textured 0.97Bi(1/2)(Na0.78K0.22) 1/2TiO3-0.03BiAlO(3) as an exemplary incipient piezoceramic, whereby texturing was achieved using a reactive templated grain-growth technique. The manufactured textured ceramic is characterized by S-max/E-max of 995 pm V-1 and an electrostrictive coefficient, Q(33), of 0.049 m(4) C-2. Both these parameters are as large as those of single crystals. The current work presents a significant advancement in the field of lead-free ceramics and can guide future efforts in this direction. In addition, the concept presented here can be easily transferred to other disciplines involving the design of functional properties of various materia