STUDY OF DOMAIN STRUCTURE IN (211)-CUT (Pb(Mg_(1/3)Nb_(2/3)O_3)_(0.7)(PbTiO_3)_(0.3) SINGLE CRYSTAL BY TEMPERATURE-DEPENDENT PIEZORESPONSE FORCE MICROSCOPY

摘要

PMN-xPT is relaxor ferroelectrics with great potential in the application of novel devices. At the morphotropic phase boundary with x approx 28 percent-36 percent of PT, PMN-xPT exhibits complex crystal structure and phase transformation, which are not fully understood yet. The ferroelectric domain evolution study may reveal the mechanism of phase transformations induced by temperature or electrical field. In this work, we report the study of domain evolution of PMN-30 percent PT single crystal by means of temperature-dependent piezoresponse force microscopy (PFM) and electrical measurement. Observation of poled (211)-cut sample under reveal that lamellar domains are developed after poling. During temperature increase, the lamellar domains become smaller, and the phase transformation from rhombohedral-orthorhombic/monoclinic-tetragonal phase is progressing according to polarization rotation. When temperature is higher than T_m, the domain contrast becomes very weak and finally disappears. After heating and cooling cycle, the polar nonosized regions and speckle-shaped microdomains with random arrangement can be observed in the PFM image.