Local twin domains and tip-voltage-induced domain switching of monoclinic MC phase in Pb(M g1/3 N b2/3) O3-0.34PbTi O3 single crystal revealed by piezoresponse force microscopy

The monoclinic (M) phases in high-performance relaxor-based ferroelectric single crystals have been recognized to be a vital structural factor for the outstanding piezoelectric property. However, due to the complexity of the structure in M phases, the understanding about it is still limited. In this paper, the local twin domains and tip-voltage-induced domain switching of the MC phase in Pb(Mg1/3Nb2/3)O3-0.34PbTiO3 (PMN-0.34PT) single crystal have been intensively investigated by piezoresponse force microscopy (PFM). By theoretically analyzing the experimental patterns of domain walls on the (001)C face, the specific MC twin domains in the initial annealed state of a selected area have been clarified, and the polarization orientation of the MC phase in this sample is determined to be at an angle of 29 to the (001)C directions. In addition, based on the evolution of domains and the motion of domain walls under the step-increased PFM tip dc voltage (Vdc), the switching process and features of different types of MC domain variants are visually revealed.