Ferroelastic domain structure and phase transition in single-crystalline [PbZn1/3Nb2/3O3](1-x)[PbTiO3](x) observed via in situ x-ray microbeam

Abstract

(1-x)Pb(Zn1/3Nb2/3)O-3-xPbTiO(3) ((1-x)PZN-xPT in short) is one of the most important piezoelectric materials. In this work, we extensively investigated (1-x)PZN-xPT (x = 0.07-0.11) ferroelectric single crystals using in-situ synchrotron mu XRD, complemented by TEM and PFM, to correlate microstructures with phase transitions. The results reveal that (i) at 25 degrees C, the equilibrium state of (1-x)PZN-xPT is a metastable orthorhombic phase for x = 0.07 and 0.08, while it shows coexistence of orthorhombic and tetragonal phases for x = 0.09 and x = 0.11, with all ferroelectric phases accompanied by ferroelastic domains; (ii) upon heating, the phase transformation in x = 0.07 is Orthorhombic -> Monoclinic -> Tetragonal -> Cubic. The coexistence of ferroelectric tetragonal and paraelectric cubic phases was in-situ observed in x = 0.08 above Curie temperature (T-C), and (iii) phase transition can be explained by the evolution of the ferroelectric and ferroelastic domains. These results disclose that (1-x)PZN-xPT are in an unstable regime, which is possible factor for its anomalous dielectric response and high piezoelectric coefficient.