Anti-phase domains and magnetism in epitaxial magnetite layers

Abstract

Document VersionPublisher's PDF, also known as Version of Record (includes final page, issue and volume numbers)Please check the document version of this publication:• A submitted manuscript is the author's version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website.• The final author version and the galley proof are versions of the publication after peer review.• The final published version features the final layout of the paper including the volume, issue and page numbers. Link to publication General rightsCopyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal ? Take down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Recent studies show that the magnetic properties of epitaxial thin films of magnetite (Fe 3 O 4 ) deviate strongly from bulk behavior: it is difficult to saturate thin films, ultrathin films may become super paramagnetic, their saturation magnetization drops to zero, and the local magnetic moments are oriented out of plane in zero field. The possible relationship between this anomalous behavior and the occurrence of anti-phase boundaries ͑APBs͒ is discussed. Transmission electron microscopy images confirm that APBs are present in our Fe 3 O 4 films grown by molecular beam epitaxy on MgO͑100͒. Only APBs with out-of-plane shift vectors are visible. The much higher APB density found in sputtered films suggests that preparation conditions are important. To explain the deviating saturation and the superparamagnetic behavior of thin Fe 3 O 4 films at the same time, the magnetic coupling over the APB must be dramatically reduced due to spin disorder along the boundaries.

Diffusive motion of antiphase domain boundaries inFe3O4films

“…Anorthite also has an fcc oxygen sublattice which is continuous across the boundary. The difference in activation energy for domain coarsening between Fe 3 It is also interesting to compare our activation energy to bulk diffusion data. A comprehensive study of the bulk diffusion in Fe 3 O 4 has been performed by Dieckmann and Schmalzried.…”

“…For instance, the saturation magnetization of Fe 3 O 4 films grown by different techniques and temperatures ͓i.e., sputtering 1 and molecular-beam epitaxy 2,3 ͑MBE͔͒ is very different and could be related to a different APB structure. 9 In this paper we present a quantitative study of the changes in APB density as a function of annealing and growth parameters.…”

Magnetization of Fe3O4/MgO multilayers studied with Mössbauer spectroscopy

“…4 we present a 1200ϫ1200 Å 2 STM image of MgO (100) Fig. 4 has a width of 550 Å and a length of 1100 Å, which is comparable to the size of the domains observed by Margulies et al 2 From STM it is difficult to obtain an average grain size, but recent transmission electron microscope pictures 11 of a 2000 Å thick MBE-grown layer show that the average domain size is in the order of 3000 Å, which is an order of magnitude larger than the domains observed by Margulies et al We do not know, however, whether the average domain size in this 2000 Å thick film is the same as in our 300 and 400 Å thick films.…”

EpitaxialZnxFe3−xO4thin films: A spintronic material with tunable electrical and magnetic properties

“…Furthermore, our systematic study provides clear evidence that their electrical conductivity is closely related to the overall magnetization. We also carefully consider the presence of anti-phase boundaries (APBs) in the thin film samples which could affect both their electrical conductivity and their saturation magnetization 28,29 . However, we have clear evidence that APBs do not play a dominant role in this study.…”