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Tuning the magnetic coupling across ultrathin antiferromagnetic films by controlling atomic-scale roughness

Nature Materials volume 5, pages 128–133 (2006)Cite this article

An Erratum to this article was published on 01 March 2006

Abstract

Characterization and control of the interface structure and morphology at the atomic level is an important issue in understanding the magnetic interaction between an antiferromagnetic material and an adjacent ferromagnet in detail, because the atomic spins in an antiferromagnet change direction on the length scale of nearest atomic distances. Despite its technological importance for the development of advanced magnetic data-storage devices and extensive studies, the details of the magnetic interface coupling between antiferromagnets and ferromagnets have remained concealed. Here we present the results of magneto-optical Kerr-effect measurements and layer-resolved spectro-microscopic magnetic domain imaging of single-crystalline ferromagnet–antiferromagnet– ferromagnet trilayers. Atomic-level control of the interface morphology is achieved by systematically varying the thicknesses of the bottom ferromagnetic and the antiferromagnetic layer. We find that the magnetic coupling across the interface is mediated by step edges of single-atom height, whereas atomically flat areas do not contribute.

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Figure 1: Effect of the thickness of the antiferromagnetic FeMn layer tFeMn and the bottom ferromagnetic Co layer tCo on the magnetization loops of single-crystalline Co–FeMn–Co trilayers, deposited on Cu(001).
Figure 2: Influence of the atomic layer filling of the bottom Co layer on the position and the strength of the antiferromagnetic interlayer coupling maximum across a single-crystalline antiferromagnetic FeMn layer in Co–FeMn–Co trilayers on Cu(001).
Figure 3: Overview of the direction of the magnetic interlayer coupling in an FeNi–FeMn–Co single-crystalline trilayer on Cu(001).
Figure 4: Overview of the direction of the magnetic interlayer coupling in Co–Ni–FeMn–Co on Cu(001).
Figure 5: Schematic explanation of the model used to explain the observed sawtooth-like behaviour of the sign of the magnetic interlayer coupling across single-crystalline antiferromagnetic FeMn layers.

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Acknowledgements

This work was supported by the German Minister of Science and Education (BMBF) under grant no. 05 KS1EFA6. We thank B. Heinrich, J. T. Kohlhepp, and M. D. Stiles for fruitful discussions.

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Authors and Affiliations

  1. Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, Halle, D-06120, Germany

    W. Kuch, L. I. Chelaru, F. Offi, J. Wang, M. Kotsugi & J. Kirschner

  2. Freie Universität Berlin, Institut für Experimentalphysik, Arnimallee 14, Berlin, D-14195, Germany

    W. Kuch

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  1. W. Kuch
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Correspondence to W. Kuch.

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Kuch, W., Chelaru, L., Offi, F. et al. Tuning the magnetic coupling across ultrathin antiferromagnetic films by controlling atomic-scale roughness. Nature Mater 5, 128–133 (2006). https://doi.org/10.1038/nmat1548

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