Abstract
The manipulation of single magnetic molecules may enable new strategies for high-density information storage and quantum-state control. However, progress in these areas depends on developing techniques for addressing individual molecules and controlling their spin. Here, we report success in making electrical contact to individual magnetic N@C60 molecules and measuring spin excitations in their electron tunnelling spectra. We verify that the molecules remain magnetic by observing a transition as a function of magnetic field that changes the spin quantum number and also the existence of non-equilibrium tunnelling originating from low-energy excited states. From the tunnelling spectra, we identify the charge and spin states of the molecule. The measured spectra can be reproduced theoretically by accounting for the exchange interaction between the nitrogen spin and electron(s) on the C60 cage.
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Acknowledgements
We thank R. Döring and O. Bäßler for their work to synthesize and purify the N@C60 and G. R. Hutchison for help with calculations. The research at Cornell was supported by the US NSF (DMR-0520404, DMR-0605742, EEC-0646547, CHE-0403806 and through use of the Cornell Nanofabrication Facility/NNIN). Work in Berlin was supported by the Bundesministerium für Bildung und Forschung under contract no. 03N8709.
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J.E.G. had the primary role in fabricating the samples, carrying out the measurements and analysing the data, with assistance from E.S.T. and J.J.P. and advice from D.C.R. C.T. carried out the model calculations. M.S. and W.H. led the molecular synthesis, purification and characterization. B.U. and H.D.A. carried out electrochemical characterization. All of the authors contributed to the data analysis and the preparation of the manuscript.
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Grose, J., Tam, E., Timm, C. et al. Tunnelling spectra of individual magnetic endofullerene molecules. Nature Mater 7, 884–889 (2008). https://doi.org/10.1038/nmat2300
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DOI: https://doi.org/10.1038/nmat2300
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