Abstract

Molecular semiconductors may exhibit antiferromagnetic correlations well below room temperature1,2,3. Although inorganic antiferromagnetic layers may exchange bias4 single-molecule magnets5, the reciprocal effect of an antiferromagnetic molecular layer magnetically pinning an inorganic ferromagnetic layer through exchange bias has so far not been observed. We report on the magnetic interplay, extending beyond the interface, between a cobalt ferromagnetic layer and a paramagnetic organic manganese phthalocyanine (MnPc) layer. These ferromagnetic/organic interfaces are called spinterfaces because spin polarization arises on them6,7,8. The robust magnetism of the Co/MnPc spinterface6,9 stabilizes antiferromagnetic ordering at room temperature within subsequent MnPc monolayers away from the interface. The inferred magnetic coupling strength is much larger than that found in similar bulk10,11, thin1 or ultrathin2 systems. In addition, at lower temperature, the antiferromagnetic MnPc layer induces an exchange bias on the Co film, which is magnetically pinned. These findings create new routes towards designing organic spintronic devices.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    et al. High-temperature antiferromagnetism in molecular semiconductor thin films and nanostructures. Nature Commun. 5, 3079 (2014).

  2. 2.

    et al. Probing superexchange interaction in molecular magnets by spin-flip spectroscopy and microscopy. Phys. Rev. Lett. 101, 197208 (2008).

  3. 3.

    et al. Molecular thin films: A new type of magnetic switch. Adv. Mater. 19, 3618–3622 (2007).

  4. 4.

    Mechanisms for exchange bias. J. Phys. D 33, R247–R268 (2000).

  5. 5.

    et al. Exchange biasing single molecule magnets: Coupling of TbPc2 to antiferromagnetic layers. Nano Lett. 12, 5703–5707 (2012).

  6. 6.

    et al. Direct observation of a highly spin-polarized organic spinterface at room temperature. Sci. Rep. 3, 1272 (2013).

  7. 7.

    et al. Interface-engineered templates for molecular spin memory devices. Nature 493, 509–513 (2013).

  8. 8.

    et al. Unravelling the role of the interface for spin injection into organic semiconductors. Nature Phys. 6, 615–620 (2010).

  9. 9.

    et al. Impact on interface spin polarization of molecular bonding to metallic surfaces. Phys. Rev. Lett. 105, 077201 (2010).

  10. 10.

    , , & Paramagnetic anisotropy, electronic structure, and ferromagnetism in spin S = 3/2 manganese(II) phthalocyanine. J. Chem. Phys. 53, 1638–1642 (2003).

  11. 11.

    , & Preparation and magnetic properties of manganese(II) phthalocyanine thin films. J. Chem. Phys. 108, 10256–10261 (1998).

  12. 12.

    Functional Phtalocyanine Molecular Materials (Springer, 2010).

  13. 13.

    , & Electronic structure and exchange interactions in cobalt-phthalocyanine chains. Phys. Rev. B 88, 024426 (2013).

  14. 14.

    et al. Induced magnetic ordering in a molecular monolayer. Chem. Phys. Lett. 411, 214–220 (2005).

  15. 15.

    et al. Substrate-induced magnetic ordering and switching of iron porphyrin molecules. Nature Mater. 6, 516–520 (2007).

  16. 16.

    et al. Chemisorption of manganese phthalocyanine on Cu(001) surface promoted by van der Waals interactions. Phys. Rev. B 87, 155418 (2013).

  17. 17.

    , , & Interface magnetic coupling of Fe-phthalocyanine layers on a ferromagnetic surface. Phys. Rev. B 87, 054420 (2013).

  18. 18.

    , , , & Control of the magnetism of cobalt phthalocyanine by a ferromagnetic substrate. Phys. Rev. B 84, 174443 (2011).

  19. 19.

    Molecular spintronics. Chem. Soc. Rev. 40, 3336–3355 (2011).

  20. 20.

    & Magnetism From Fundamentals to Nanoscale Dynamics (Springer, 2006).

  21. 21.

    et al. Electronic configuration of Mn ions in the π-d molecular ferromagnet β-Mn phthalocyanine studied by soft X-ray magnetic circular dichroism. Solid State Commun. 152, 806–809 (2012).

  22. 22.

    , & Effect of Coulomb interaction on the X-Ray magnetic circular dichroism spin sum rule in 3d transition elements. J. Phys. Soc. Jpn 65, 1053–1055 (1996).

  23. 23.

    et al. Asymmetric magnetization reversal in exchange-biased hysteresis loops. Phys. Rev. Lett. 84, 3986–3989 (2000).

  24. 24.

    , & A new paradigm for exchange bias in polycrystalline thin films. J. Magn. Magn. Mater. 322, 883–899 (2010).

  25. 25.

    et al. The 2014 Magnetism Roadmap. J. Phys. D 47, 333001 (2014).

  26. 26.

    et al. DEIMOS: A beamline dedicated to dichroism measurements in the 350–2500 eV energy range. Rev. Sci. Instrum. 85, 013106 (2014).

  27. 27.

    et al. Fast continuous energy scan with dynamic coupling of the monochromator and undulator at the DEIMOS beamline. J. Synchrotron Radiat. 21, 502–506 (2014).

Download references

Acknowledgements

We thank B. Muller, A. Boulard, B. Leconte and C. Kieber for technical assistance. We thank D. Lacour and Y. Henry for scientific insight. We thank P. Rengasamy, G. Schmerber and C. Ulhaq for auxiliary measurements. We acknowledge funding from the Franco-German University and the Baden-Württemberg Stiftung in the framework of the Kompetenznetz für Funktionale Nanostrukturen (KFN), from the Alexander von Humboldt foundation, from the Institut Carnot MICA’s ‘Spinterface’ grant, from the Agence Nationale de la Recherche ANR-09-JCJC-0137 and ANR-11-LABX-0058 NIE and from the International Center for Frontier Research in Chemistry. The MBE chamber used during our beamtime on DEIMOS was funded by the Agence National de la Recherche; grant ANR-05-NANO-073. This work was performed using HPC resources from the Strasbourg Mesocenter and from GENCI-CINES Grant 2014-gem1100.

Author information

Affiliations

  1. Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, 23 rue du Loess, BP 43 F-67034 Strasbourg Cedex 2, France

    • Manuel Gruber
    • , Fatima Ibrahim
    • , Samy Boukari
    • , Loïc Joly
    • , Michał Studniarek
    • , Victor Da Costa
    • , Hashim Jabbar
    • , Vincent Davesne
    • , Ufuk Halisdemir
    • , Jacek Arabski
    • , Fabrice Scheurer
    • , Wolfgang Weber
    • , Mebarek Alouani
    • , Eric Beaurepaire
    •  & Martin Bowen
  2. Physikalisches Institut, Karlsruhe Institute of Technology, Wolfgang-Gaede-Strasse 1 76131 Karlsruhe, Germany

    • Manuel Gruber
    • , Hironari Isshiki
    • , Moritz Peter
    • , Vincent Davesne
    • , Jinjie Chen
    •  & Wulf Wulfhekel
  3. Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France

    • Michał Studniarek
    • , Edwige Otero
    • , Fadi Choueikani
    • , Kai Chen
    •  & Philippe Ohresser
  4. Institute of Nanotechnology, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany

    • Wulf Wulfhekel

Authors

  1. Search for Manuel Gruber in:

  2. Search for Fatima Ibrahim in:

  3. Search for Samy Boukari in:

  4. Search for Hironari Isshiki in:

  5. Search for Loïc Joly in:

  6. Search for Moritz Peter in:

  7. Search for Michał Studniarek in:

  8. Search for Victor Da Costa in:

  9. Search for Hashim Jabbar in:

  10. Search for Vincent Davesne in:

  11. Search for Ufuk Halisdemir in:

  12. Search for Jinjie Chen in:

  13. Search for Jacek Arabski in:

  14. Search for Edwige Otero in:

  15. Search for Fadi Choueikani in:

  16. Search for Kai Chen in:

  17. Search for Philippe Ohresser in:

  18. Search for Wulf Wulfhekel in:

  19. Search for Fabrice Scheurer in:

  20. Search for Wolfgang Weber in:

  21. Search for Mebarek Alouani in:

  22. Search for Eric Beaurepaire in:

  23. Search for Martin Bowen in:

Contributions

M.G., S.B., E.B. and M.B. conceived and designed the experiments. J.A. purified the molecules. M.G., L.J., V.D.C., S.B., M.S., H.I., M.P., H.J., V.D.C., F.S., W.Weber, E.B. and M.B. carried out XAS measurements. M.G., S.B., M.B., V.D.C., U.H., W.Weber and E.B. carried out MOKE experiments. H.I., J.C. and W.Wulfhekel performed STM experiments. M.G. analysed the data. F.I. and M.A. performed the ab initio study. F.C., E.O., K.C. and P.O. performed control experiments. M.G., M.B. and E.B. co-wrote the paper. All the authors discussed the results and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Manuel Gruber or Eric Beaurepaire or Martin Bowen.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    Supplementary Information

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nmat4361