Mesoscopic polarization structures such as polar nanoregions and polarization domain walls are the key factors that connecting microscopic fundamental polarization structures with macroscopic practical dielectric properties. Snapshot observation of domain in the relaxor-ferroelectrics PMN-x%PT just vicinity of morphotropic phase boundary region was performed by use of 7 ps single shot soft X-ray laser pulse. A self-assembled evolution of oblique polarization domain was observed in PMN-27.8%PT under the sample temperature decreased with thermal equilibrium condition. Based on energetic discussion, anti-phase shift of domain wall pairs keeping with flat boundaries was proposed for the dielectric response. A sharp enhancement in dielectric response at the vicinity of morphotropic phase boundary region reported previously was recognized as an evidence for hierarchic nature of the present oblique polarization domain wall.
