[101]‐Oriented Pb(Mg _1/3 Nb _2/3 )O ₃ –PbTiO ₃ Single Crystals Under Electric Loadings: Polarization Rotation Linking <i>M</i> _B , <i>O</i> , and <i>R</i> Phases

Abstract

We report on the existence of monoclinic ( M B ), orthohombic ( O ), and rhombohedral ( R ) phases in [101]‐oriented 74Pb(Mg 1/3 Nb 2/3 )O 3 –26PbTiO 3 (PMN–26PT) single crystals under electric loadings. Before electric loadings, the [101]‐oriented PMN–26PT single crystal is composed of R and monoclinic phases. Both M B and R phases are revealed after being poled in the [101] direction. When the single crystal is subjected to bipolar cyclic electric field, an M B phase bridges the reversal of domains of R phase. Reversal of the domains of M B phase is achieved by either 180° domain switching or non‐180° domain switchings. Under static electric field, polarization rotation from R to M B again occurs, and as the field increases, phase transition from M B to O phase occurs. The O phase is metastable because it tends to change back to M B phase after the removal of electric field. The findings are of importance for understanding the microstructure characteristics of [101]‐oriented PMN–PT single crystals that show the ultrahigh piezoelectric performances at the morphotropic phase boundary.