Effects of polymeric filler on polarization fatigue of 1-3 0.74Pb(Mg_1/3Nb_2/3)O₃-0.26PbTiO₃ single crystal/polymer composites

Polarization fatigue tests have been conducted on both bulk Pb(Mg_1/3Nb_2/3)O₃-xPbTiO₃ (PMN-xPT) single crystals and two 1-3 PMN-xPT/polymer composites with both "soft" and "hard" epoxy fillers, respectively. The variations of remnant polarization, coercive electric field, and micro-crack morphology under 10 Hz cyclic electric loading were studied. It was found that the magnitude of coercive field for both composites was higher compared to that of single crystals. However, as the number of cycles increases, the degradation ratio of remnant polarization and the increased portion of coercive field for both composites were lower than that of single crystals; the sequence is PMN-0.26PT bulk single crystal > 1-3 PMN-0.26PT/soft epoxy composites > 1-3 PMN-0.26PT/hard epoxy composites. In addition, the observed micro-crack propagation morphology shows that 1-3 PMN-0.26PT/hard epoxy composites can substantially improve fatigue-resistance owing to the lower stretching strain benefiting from the polymeric filler. Our results indicated that 1-3 PMN-0.26PT/polymer composites present much better electric polarization stability.