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Atom-by-atom engineering and magnetometry of tailored nanomagnets

Nature Physics volume 8, pages 497–503 (2012)Cite this article

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Abstract

Nanomagnets, namely arrays of a few exchange-coupled atomic magnetic moments, possess a rich variety of magnetic properties and are explored as constituents of nanospintronics technologies. They have been realized as magnetic clusters or molecular nanomagnets. Individual nanomagnets, built from magnetic atoms adsorbed onto a nonmagnetic surface (adatoms) coupled by Ruderman–Kittel–Kasuya–Yosida exchange, exhibit a high level of versatility resulting from distance-dependent interactions. Here, we combine spin-resolved scanning tunnelling microscopy, atom manipulation and simulations to tailor nanomagnets ranging from linear chains to complex two-dimensional arrays and perform magnetometry in an atom-by-atom fashion. Distinct ground states of each chain, depending on even or odd numbers of constituent atoms, and magnetic frustration within the arrays have been observed directly. Our work demonstrates real-space access to the magnetic states of tailored nanostructures providing an approach to tackling open fundamental questions in magnetism.

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Figure 1: Distance dependency of pairwise RKKY interaction energy.
Figure 2: Antiferromagnetic chains of even and odd numbers of Fe atoms.
Figure 3: Equilateral antiferromagnetic triplets.
Figure 4: Antiferromagnetic ‘flower’.
Figure 5: Antiferromagnetic ‘kagome’.

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Acknowledgements

Financial support from the European Research Council (ERC) Advanced Grant ‘FURORE’, by the Deutsche Forschungsgemeinschaft via the SFB668, as well as by the city of Hamburg via the cluster of excellence ‘Nanospintronics’ is gratefully acknowledged. S.L. acknowledges the support of the HGF-YIG Programme Funsilab—Functional Nanoscale Structure Probe and Simulation Laboratory (VH-NG-717). S. B. acknowledges support by the Helmholtz Association via grant POF-HGF-FIT. We would like to thank D. L. Mills, E. Y. Vedmedenko, R. Wieser, K. Them, P. H. Dederichs and N. P. Konstantinidis for fruitful discussions.

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Authors and Affiliations

  1. Institute of Applied Physics, Hamburg University, Jungiusstrasse 11, D-20355 Hamburg, Germany

    Alexander Ako Khajetoorians, Jens Wiebe, Bruno Chilian & Roland Wiesendanger

  2. Peter Grünberg Institut and Institute for Advanced Simulation, Forschungszentrum Jülich & JARA, D-52425 Jülich, Germany

    Samir Lounis & Stefan Blügel

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  1. Alexander Ako Khajetoorians
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Contributions

A.A.K. and B.C. performed the experiments. A.A.K., B.C. and J.W. carried out the data analysis. S.L. carried out and analysed the ab initio calculations. J.W. and A.A.K wrote the paper. All authors discussed the results and commented on the manuscript.

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Correspondence to Jens Wiebe.

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Khajetoorians, A., Wiebe, J., Chilian, B. et al. Atom-by-atom engineering and magnetometry of tailored nanomagnets. Nature Phys 8, 497–503 (2012). https://doi.org/10.1038/nphys2299

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