Enhanced bipolar fatigue resistance in PMN-PZT ceramics prepared by spark plasma sintering

The bipolar fatigue behaviors of lead magnesium niobate-lead zirconate titanate (PMN-PZT) ceramics sintered by conventional sintering (CS) and spark plasma sintering (SPS) were systematically investigated. Significantly enhanced bipolar fatigue resistance was observed for SPS samples by a comparative analysis of the evolution of both large signal (polarization, strain) and small signal (piezoelectric coefficient, permittivity) hysteresis curves. The enhanced fatigue resistance is not only attributed to the suppressed development of microcracks, which is due to the decrease in grain size and porosity, but is also related to the reduction of domain wall pinning effect induced by migratory point defects, especially oxygen vacancies. Besides, the different phase structure and its evolution upon poling and fatigue are also responsible for the enhanced fatigue resistance.