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Strain relaxation in Fe{sub 3}O{sub 4}/MgAl{sub 2}O{sub 4} heterostructures: Mechanism for formation of antiphase boundaries in an epitaxial system with identical symmetries of film and substrate

Journal Article · · Physical Review. B, Condensed Matter and Materials Physics
 [1]; ; ;  [2]
  1. Institut fuer Festkoerperforschung und Ernst Ruska-Centrum, Forschungszentrum Juelich, D-52425 Juelich (Germany)
  2. Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), School of Physics, Trinity College Dublin, Dublin 2 (Ireland)
Strain relaxation studies in epitaxial magnetite, Fe{sub 3}O{sub 4}, thin films grown on MgAl{sub 2}O{sub 4}(100) substrates are reported. The study shows that the films were relaxed in line with the theoretical model prediction with a critical thickness, t{sub c}=5 nm. Antiphase boundaries (APBs) are not expected to form in Fe{sub 3}O{sub 4} films grown on MgAl{sub 2}O{sub 4} substrates because both film and substrate have the same crystal symmetry. In contrast, our study reveals the formation of APBs within the Fe{sub 3}O{sub 4} films. Our analysis shows that the APBs in a Fe{sub 3}O{sub 4}/MgAl{sub 2}O{sub 4} heteroepitaxial system are formed by partial dislocations, which accommodate the misfit. This formation mechanism of APBs is fundamentally different from the one found in the Fe{sub 3}O{sub 4}/MgO system, where APBs are formed as a consequence of equivalent nucleation sites on the MgO substrate separated by nontranslational vectors of the Fe{sub 3}O{sub 4} lattice. The mechanism for the formation of antiphase boundaries through partial dislocations should be applicable to a wide range of epitaxial systems having identical symmetries of the film and the substrate and significant lattice mismatch.
OSTI ID:
21287041
Journal Information:
Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 2 Vol. 80; ISSN 1098-0121
Country of Publication:
United States
Language:
English