S25 The Reverse of Triaxial Strain Fields in a Multiferroic BiFeO3 Thin Film As Studied Using Scanning X-ray Microdiffraction

Abstract

The dramatically enhanced polarizations and saturation magnetizations observed in the epitaxially constrained BiFeO3 (BFO) thin films with their pronounced grain-orientation dependence have attracted much attention and are attributed largely to the constrained in-plane strain. Thus, it is highly desirable to directly obtain information on the two-dimensional (2D) distribution of the in-plane strain and its correlation with the grain orientation of each corresponding micro-region. Here we report a 2D quantitative mapping of the grain orientation and the local triaxial strain-field in a 250nm-thick multiferroic BFO film using a synchrotron x-ray microdiffraction technique. This direct scanning measurement demonstrates that the deviatoric component of the in-plane strain tensor is between 5x10 and 6x10 and that the local triaxial strain is fairly well correlated with the grain orientation in that particular region at room temperature. We have performed a 2D quantitative mapping of the grain orientation and the local triaxial strain-field in a BiFeO3 thin film at room temperature, 373K, 673K by using a synchrotron X-ray microdiffraction technique. This direct scanning measurement demonstrates that the deviatoric component of the in-plane strain tensor is reversed with temperature raising, and that the local triaxial strain is fairly well correlated with the grain orientation in that particular region.