Electromechanical Displacement Of Piezoelectric-electrostrictive Monolithic Bilayer Composites

摘要

We examine the electromechanical displacement of piezoelectric-electrostrictive monolithic bilayer composites with various piezoelectric volume percentage obtained by cosintering piezoelectric 0.65Pb(Mg_(1/3) Nb_(2/3))O_3-0.35PbTiO_3 and electrostrictive 0.9Pb(Mg_(1/3)Nb_(2/3))O_3-0.1PbTiO_3 under unipolar and bipolar electric field excitation up to 10 kV/cm experimentally. It is shown that the effective d_(33) of the composites is limited by the electrostrictive layer, which acts as a capacitor in series to the piezoelectric layer, causing incomplete poling. We show that by controlling the volume content of the piezoelectric layer and constraining it with an electrostrictor, substantial strain amplification (15 μm for bipolar excitation) can be achieved while inducing asymmetry to the displacement with respect to the polarity of the applied field, which we discuss in the context of symmetry superposition.