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Morphology, Structure, and Nucleation of Out-of-Phase Boundaries (OPBs) in Epitaxial Films of Layered Complex Oxides



M A. Zurbuchen, W Tian, X Q. Pan, D Fong, S K. Streiffer, M E. Hawley, J Lettieri, Y Jia, Shengqian Ma, S J. Fulk, D J. Comstock, S Knapp, A H. Carim, D G. Schlom


Out-of-phase boundaries (OPBs) are translation boundary defects characterized by a misregistry of a fraction of a unit cell dimension in neighboring regions of a crystal. Although rarely observed in the bulk, they are common in epitaxial films of layered oxides due to the physical constraint of the underlying substrate and low degree of structural rearrangement during growth. OPBs can strongly affect properties, but no extensive studies of them are available. The morphology, structure, and nucleation mechanisms of OPBs in epitaxial films of layered complex oxides are presented, including both a review of published studies and new work. Morphological trends in the Aurivillius and Ruddlesden-Popper series of layered oxide phases are described. The atomic structure at two types of these defects is presented. OPBs may be introduced into a film at various times during or after growth. Primary mechanisms occur at film nucleation, and include steric, nucleation layer, ab-misfit, and inclined-c misfit. Secondary nucleation occurs by crystallographic shear in an existing film in response to loss of a volatile component. Mechanism descriptions are accompanied by experimental examples. Alternative methods to the direct imaging of OPBs are also presented.
Journal of Materials Research


Aurivillius phase, complex oxide, ferroelectric, layered oxide, out-of-phase boundary, perovskite, Ruddlesden-Popper phases, superconductor, transmission electron microscopy


Zurbuchen, M. , Tian, W. , Pan, X. , Fong, D. , Streiffer, S. , Hawley, M. , Lettieri, J. , Jia, Y. , Ma, S. , Fulk, S. , Comstock, D. , Knapp, S. , Carim, A. and Schlom, D. (2017), Morphology, Structure, and Nucleation of Out-of-Phase Boundaries (OPBs) in Epitaxial Films of Layered Complex Oxides, Journal of Materials Research (Accessed July 24, 2024)


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Created February 19, 2017