Magnetic memory of a single-molecule quantum magnet wired to a gold surface


In the field of molecular spintronics1, the use of magnetic molecules for information technology is a main target and the observation of magnetic hysteresis on individual molecules organized on surfaces is a necessary step to develop molecular memory arrays. Although simple paramagnetic molecules can show surface-induced magnetic ordering and hysteresis when deposited on ferromagnetic surfaces2, information storage at the molecular level requires molecules exhibiting an intrinsic remnant magnetization, like the so-called single-molecule magnets3 (SMMs). These have been intensively investigated for their rich quantum behaviour4 but no magnetic hysteresis has been so far reported for monolayers of SMMs on various non-magnetic substrates, most probably owing to the chemical instability of clusters on surfaces5. Using X-ray absorption spectroscopy and X-ray magnetic circular dichroism synchrotron-based techniques, pushed to the limits in sensitivity and operated at sub-kelvin temperatures, we have now found that robust, tailor-made Fe4 complexes retain magnetic hysteresis at gold surfaces. Our results demonstrate that isolated SMMs can be used for storing information. The road is now open to address individual molecules wired to a conducting surface6,7 in their blocked magnetization state, thereby enabling investigation of the elementary interactions between electron transport and magnetism degrees of freedom at the molecular scale8,9.

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Figure 1: Monolayer of Fe4 on gold.
Figure 2: XAS/XMCD of Fe4 monolayer.
Figure 3: Hysteresis and magnetization dynamics of Fe4 monolayer.


  1. 1

    Rocha, A. R. et al. Towards molecular spintronics. Nature Mater. 4, 335–339 (2005).

  2. 2

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

  3. 3

    Sessoli, R., Gatteschi, D., Caneschi, A. & Novak, M. A. Magnetic bistability in a metal-ion cluster. Nature 365, 141–143 (1993).

  4. 4

    Gatteschi, D., Sessoli, R. & Villain, J. Molecular Nanomagnets (Oxford Univ. Press, 2006).

  5. 5

    Mannini, M. et al. XAS and XMCD investigation of Mn12 monolayers on gold. Chem. Eur. J. 14, 7530–7535 (2008).

  6. 6

    Heersche, H. B. et al. Electron transport through single Mn12 molecular magnets. Phys. Rev. Lett. 96, 206801 (2006).

  7. 7

    Jo, M. H. et al. Signatures of molecular magnetism in single-molecule transport spectroscopy. Nano Lett. 6, 2014–2020 (2006).

  8. 8

    Kim, G. H. & Kim, T. S. Electronic transport in single-molecule magnets on metallic surfaces. Phys. Rev. Lett. 92, 137203 (2004).

  9. 9

    Bogani, L. & Wernsdorfer, W. Molecular spintronics using single-molecule magnets. Nature Mater. 7, 179–186 (2008).

  10. 10

    Ziemelis, K. Nature Milestones Spin, Milestone 22: (1996) Mesoscopic tunnelling of magnetization (10.1038/nphys877).

  11. 11

    Leuenberger, M. N. & Loss, D. Quantum computing in molecular magnets. Nature 410, 789–793 (2001).

  12. 12

    Wiesendanger, R. Scanning Probe Microscopy and Spectroscopy Methods and Applications (Cambridge Univ. Press, 1994).

  13. 13

    Cornia, A. et al. Preparation of novel materials using SMMs. Struct. Bond. 122, 133–161 (2006).

  14. 14

    Madhavan, V., Chen, W., Jamneala, T., Crommie, M. F. & Wingreen, N. S. Tunneling into a single magnetic atom: Spectroscopic evidence of the Kondo resonance. Science 280, 567–569 (1998).

  15. 15

    Heinze, S. et al. Real-space imaging of two-dimensional antiferromagnetism on the atomic scale. Science 288, 1805–1808 (2000).

  16. 16

    Hirjibehedin, C. F., Lutz, C. P. & Heinrich, A. J. Spin coupling in engineered atomic structures. Science 312, 1021–1024 (2006).

  17. 17

    Zhao, A. et al. Controlling the Kondo effect of an adsorbed magnetic ion through its chemical bonding. Science 309, 1542–1544 (2005).

  18. 18

    Durkan, C. & Welland, M. E. Electronic spin detection in molecules using scanning-tunneling-microscopy-assisted electron-spin resonance. Appl. Phys. Lett. 80, 458–460 (2002).

  19. 19

    Iacovita, C. et al. Visualizing the spin of individual cobalt-phthalocyanine molecules. Phys. Rev. Lett. 101, 116602 (2008).

  20. 20

    Mannini, M. et al. X-ray magnetic circular dichroism picks out single-molecule magnets suitable for nanodevices. Adv. Mater. 21, 167–171 (2009).

  21. 21

    Stöhr, J. Exploring the microscopic origin of magnetic anisotropies with x-ray magnetic circular dichroism (XMCD) spectroscopy. J. Magn. Magn. Mater. 200, 470–497 (1999).

  22. 22

    Gambardella, P. et al. Ferromagnetism in one-dimensional monoatomic metal chains. Nature 416, 301–304 (2002).

  23. 23

    Cornia, A. et al. Energy-barrier enhancement by ligand substitution in tetrairon(III) single-molecule magnets. Angew. Chem. Int. Ed. 43, 1136–1139 (2004).

  24. 24

    Accorsi, S. et al. Tuning anisotropy barriers in a family of tetrairon(III) single-molecule magnets with an S=5 ground state. J. Am. Chem. Soc. 128, 4742–4755 (2006).

  25. 25

    Barra, A. L. et al. New single-molecule magnets by site-specific substitution: Incorporation of ‘alligator clips’ into Fe4 complexes. Eur. J. Inorg. Chem. 4145–4152 (2007).

  26. 26

    Ulman, A. Formation and structure of self-assembled monolayers. Chem. Rev. 96, 1533–1554 (1996).

  27. 27

    Sainctavit, Ph. & Kappler, J.-P. in X-ray Magnetic Circular Dichroism at Low Temperature in Magnetism and Synchrotron Radiation (eds Beaurepaire, E., Scheurer, F., Krill, G. & Kappler, J.-P.) 135–153 (Springer, 2001).

  28. 28

    Letard, I. et al. Remnant magnetization of Fe8 high-spin molecules: X-ray magnetic circular dichroism at 300 mK. J. Appl. Phys. 101, 113920 (2007).

  29. 29

    Nakajima, R., Stohr, J. & Idzerda, Y. U. Electron-yield saturation effects in L-edge x-ray magnetic circular dichroism spectra of Fe, Co, and Ni. Phys. Rev. B 59, 6421–6429 (1999).

  30. 30

    Parkin, S. S. P., Hayashi, M. & Thomas, L. Magnetic domain-wall racetrack memory. Science 320, 190–194 (2008).

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We acknowledge F. Scheurer, J. P. Kappler and B. Muller for their help in the installation of the endstation, and the staff of the X11MA-SIM (Swiss Light Source, Paul Scherrer Institut, Villigen, Switzerland) and UE46-PGM (BESSY synchrotron, Berlin, Germany) beamlines for their support. In particular, we thank A. Fraile-Rodriguez, L. Joly and F. Nolting for their excellent technical support at the X11MA-SIM beamline. We thank L. Gorini for his contribution to the development of the ligand synthesis and M. Etienne for his help in artwork preparation. This research project has been supported by the EU, within the EU FP6, through the Key Action: Strengthening the European Research Area, Research Infrastructures, through NoE MAGMANet, through the Integrated Infrastructure Initiative ‘Integrating Activity on Synchrotron and Free Electron Laser Science’ and through the ERANET project ‘NanoSci-ERA: NanoScience in the European Research Area’. It has been partially financially supported by the Italian CNR and MIUR and by the German DFG.

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Correspondence to Roberta Sessoli.

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Mannini, M., Pineider, F., Sainctavit, P. et al. Magnetic memory of a single-molecule quantum magnet wired to a gold surface. Nature Mater 8, 194–197 (2009) doi:10.1038/nmat2374

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