Property enhancement in relaxor-PbTiO3 single crystals by alternating current poling: Evaluation of intrinsic and extrinsic contributions

Piezoelectric activity has always been the most concerned performance for PbTiO3-based relaxor ferroelectrics. Recently, the alternating current poling (ACP) method has been developed as a simple and economical technique to optimize piezoelectric performance. However, the mechanism of the ACP method is still debatable. In this work, we carried out the ACP on the 0.27Pb(In1/2Nb1/2)O-3-0.46Pb(Mg1/3Nb2/3)O-3-0.27PbTiO(3) single crystal, a noticeable piezoelectric improvement of 20% has been achieved in comparison with the direct current poled sample, meanwhile, the dielectric loss is reduced by 26%. We found that the ACP sample demonstrates a uniform domain pattern with a large domain size dominated by 109 degrees domain walls, in contrary to the complicated domain structures which contain both 109 degrees and 71 degrees domains in the DCP sample. With this uniform and simple domain structure, the crystal lattice is weakly constrained and very susceptive to external stimulation, resulting in enhanced piezoelectric response in ACP poled sample. Meanwhile, dielectric loss is reduced for the low domain wall density. The current work gives a comprehensive description of the ACP poled samples, including the microscopic domain structure, the quantitative estimation of contributions arise from lattice deformation and domain wall motions, and reveals the interactions between domain structure and the macro performance, which provide important guidelines for the design of high-performance ferroelectrics utilizing domain tailoring techniques.