Influence of poling condition on crystal-rod domain configuration in 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 single crystal/epoxy 1-3 composites

Using the translucent nature of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 single crystals, we have studied the changes of stress distributions and domain configuration inside the PMN-0.26PT and PMN-0.33PT single crystal rods embedded in 1-3 composites by polarizing light microscopy (PLM) and piezoresponse force microscopy (PFM). When the poling temperature is above the glass transition temperature of polymeric filler, the Young's modulus of the epoxy decreases significantly, leading to the interface stress on the rods decreased by up to 3 orders of magnitude, which was verified by finite element simulation using Comsol. In addition, high temperature (70 °C or 110 °C) poling causes reduced effect on the rod edges and improves the electromechanical coefficient by about 6% for the 1-3 composites. According to observed domain configurations, the extra boundary stress was insufficient to prevent polarization switching or to induce new phase, but crystal structural deformation was observed near the rod edges.