Abstract
The switching characteristics of ferroelectrics and multiferroics are influenced by the interaction of topological defects with domain walls.We report on the pinning of polarization due to antiphase boundaries in thin films of the multiferroic hexagonal YbFeO3.We have directly resolved the atomic structure of a sharp antiphase boundary(APB)in YbFeO3 thin films using a combination of aberration-corrected scanning transmission electron microscopy(STEM)and total energy calculations based on density-functional theory(DFT).We find the presence of a layer of FeO6 octahedra at the APB that bridges the adjacent domains.STEM imaging shows a reversal in the direction of polarization on moving across the APB,which DFT calculations confirm is structural in nature as the polarization reversal reduces the distortion of the FeO6 octahedral layer at the APB.Such APBs in hexagonal perovskites are expected to serve as domain-wall pinning sites and hinder ferroelectric switching of the domains.
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