Synchrotron X-Ray Diffraction Study of the Surface Layer in Poled Ceramic BaTiO3#

Abstract

AbstractBoth unpoled and poled BaTiO3 were studied by laboratory and synchrotron x-ray sources. The shorter-wavelength synchrotron radiation was used to probe deeper below the specimen surface. Diffraction patterns revealed a distinctive surface layer of the same tetragonal structure as the main BaTiO3 fraction. A sin2 Ψ analysis of peak shift confirmed that no measurable change of elastic strain occurs upon poling. This indicates that poling may induce excessive strain that was relieved by microcracking or that a majority of domains reverse orientation. However, domain switching and possible microcracking may induce inhomogeneous strain (microstrain) and alter domain-size distribution. Line-broadening analysis showed large anisotropy of both coherently diffracting domain size and microstrain. The poled specimen shows a larger microstrain and smaller average domain size, which indicates possible effects of microcracking and additional defects created during poling.