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Beating the Stoner criterion using molecular interfaces


Only three elements are ferromagnetic at room temperature: the transition metals iron, cobalt and nickel. The Stoner criterion explains why iron is ferromagnetic but manganese, for example, is not, even though both elements have an unfilled 3d shell and are adjacent in the periodic table: according to this criterion, the product of the density of states and the exchange integral must be greater than unity for spontaneous spin ordering to emerge1,2. Here we demonstrate that it is possible to alter the electronic states of non-ferromagnetic materials, such as diamagnetic copper and paramagnetic manganese, to overcome the Stoner criterion and make them ferromagnetic at room temperature. This effect is achieved via interfaces between metallic thin films and C60 molecular layers. The emergent ferromagnetic state exists over several layers of the metal before being quenched at large sample thicknesses by the material’s bulk properties. Although the induced magnetization is easily measurable by magnetometry, low-energy muon spin spectroscopy3 provides insight into its distribution by studying the depolarization process of low-energy muons implanted in the sample. This technique indicates localized spin-ordered states at, and close to, the metal–molecule interface. Density functional theory simulations suggest a mechanism based on magnetic hardening of the metal atoms, owing to electron transfer4,5. This mechanism might allow for the exploitation of molecular coupling to design magnetic metamaterials using abundant, non-toxic components such as organic semiconductors. Charge transfer at molecular interfaces may thus be used to control spin polarization or magnetization, with consequences for the design of devices for electronic, power or computing applications (see, for example, refs 6 and 7).

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Figure 1: Effect of molecular interfaces.
Figure 2: Room-temperature magnetization for Cu and Mn films.
Figure 3: Muon spin rotation (μSR) spectroscopy at 250 K.
Figure 4: DFT simulations and metamagnetic modellling.


  1. Stoner, E. C. Collective electron ferromagnetism. Proc. R. Soc. London Ser. A 165, 372–414 (1938)

    Article  ADS  Google Scholar 

  2. Stoner, E. C. Collective electron ferromagnetism. II. Energy and specific heat. Proc. R. Soc. London Ser. A 169, 339–371 (1939)

    Article  CAS  ADS  Google Scholar 

  3. Drew, A. J. et al. Direct measurement of the electronic spin diffusion length in a fully functional organic spin valve by low-energy muon spin rotation. Nature Mater. 8, 109–114 (2009)

    Article  CAS  ADS  Google Scholar 

  4. Vandewal, K. et al. Efficient charge generation by relaxed charge-transfer states at organic interfaces. Nature Mater. 13, 63–68 (2014)

    Article  CAS  ADS  Google Scholar 

  5. Callsen, M., Caciuc, V., Kiselev, N., Atodiresei, N. & Bluegel, S. Magnetic hardening induced by nonmagnetic organic molecules. Phys. Rev. Lett. 111, 106805 (2013)

    Article  ADS  Google Scholar 

  6. Moodera, J. S., Koopmans, B. & Oppeneer, P. M. On the path toward organic spintronics. MRS Bull. 39, 578–581 (2014)

    Article  CAS  Google Scholar 

  7. Raman, K. V. Interface-assisted molecular spintronics. Appl. Phys. Rev. 1, 031101 (2014)

    Article  ADS  Google Scholar 

  8. Beeler, M. C. et al. The spin Hall effect in a quantum gas. Nature 498, 201–204 (2013)

    Article  CAS  ADS  Google Scholar 

  9. Eerenstein, W., Mathur, N. D. & Scott, J. F. Multiferroic and magnetoelectric materials. Nature 442, 759–765 (2006)

    Article  CAS  ADS  Google Scholar 

  10. Powell, A. K. Molecular magnetism: a bridge to higher ground. Nature Chem. 2, 351–352 (2010)

    Article  MathSciNet  CAS  ADS  Google Scholar 

  11. Geng, Y. et al. Direct visualization of magnetoelectric domains. Nature Mater. 13, 163–167 (2014)

    Article  CAS  ADS  Google Scholar 

  12. Warner, M. et al. Potential for spin-based information processing in a thin-film molecular semiconductor. Nature 503, 504–508 (2013)

    Article  CAS  ADS  Google Scholar 

  13. Maccherozzi, F. et al. Evidence for a magnetic proximity effect up to room temperature at Fe/(Ga,Mn) As interfaces. Phys. Rev. Lett. 101, 267201 (2008)

    Article  CAS  ADS  Google Scholar 

  14. Vobornik, I. et al. Magnetic proximity effect as a pathway to spintronic applications of topological insulators. Nano Lett. 11, 4079–4082 (2011)

    Article  CAS  ADS  Google Scholar 

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

    Article  CAS  ADS  Google Scholar 

  16. Sanvito, S. Molecular spintronics: the rise of spinterface science. Nature Phys. 6, 562–564 (2010)

    Article  CAS  ADS  Google Scholar 

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

    Article  CAS  ADS  Google Scholar 

  18. Brede, J. et al. Long-range magnetic coupling between nanoscale organic-metal hybrids mediated by a nanoskyrmion lattice. Nature Nanotechnol. 9, 1018–1023 (2014)

    Article  CAS  ADS  Google Scholar 

  19. Pai, W. W. et al. Optimal electron doping of a C60 monolayer on Cu(111) via interface reconstruction. Phys. Rev. Lett. 104, 036103 (2010)

    Article  ADS  Google Scholar 

  20. Xu, G. et al. Detailed low-energy electron diffraction analysis of the (4 × 4) surface structure of C60 on Cu(111): seven-atom-vacancy reconstruction. Phys. Rev. B 86, 075419 (2012)

    Article  ADS  Google Scholar 

  21. Tamai, A. et al. Electronic structure at the C60/metal interface: an angle-resolved photoemission and first-principles study. Phys. Rev. B 77, 075134 (2008)

    Article  ADS  Google Scholar 

  22. Cho, S. W. et al. Origin of charge transfer complex resulting in ohmic contact at the C60/Cu interface. Synth. Met. 157, 160–164 (2007)

    Article  CAS  Google Scholar 

  23. Zhang, X. et al. Observation of a large spin-dependent transport length in organic spin valves at room temperature. Nature Commun. 4, 1392 (2013)

    Article  ADS  Google Scholar 

  24. Moorsom, T. et al. Spin-polarized electron transfer in ferromagnet/C60 interfaces. Phys. Rev. B 90, 125311 (2014)

    Article  ADS  Google Scholar 

  25. Tseng, T.-C. et al. Charge-transfer-induced structural rearrangements at both sides of organic/metal interfaces. Nature Chem. 2, 374–379 (2010)

    Article  CAS  ADS  Google Scholar 

  26. Janak, J. F. Uniform susceptibilities of metallic elements. Phys. Rev. B 16, 255–262 (1977)

    Article  CAS  ADS  Google Scholar 

  27. Morenzoni, E. et al. Implantation studies of keV positive muons in thin metallic layers. Nucl. Instrum. Methods B192, 254–266 (2002)

    Article  ADS  Google Scholar 

  28. Ansaldo, E. J., Niedermayer, C. & Stronach, C. E. Muonium in fullerite. Nature 353, 121 (1991)

    Article  CAS  ADS  Google Scholar 

  29. Duty, T. L. et al. Zero-field μSR in crystalline C60 . Hyperfine Interact. 86, 789–795 (1994)

    Article  CAS  ADS  Google Scholar 

  30. Coey, J. M. D. d0 ferromagnetism. Solid State Sci. 7, 660–667 (2005)

    Article  CAS  ADS  Google Scholar 

  31. Bakule, P. & Morenzoni, E. Generation and applications of slow polarized muons. Contemp. Phys. 45, 203–225 (2004)

    Article  CAS  ADS  Google Scholar 

  32. Prokscha, T. et al. The new μE4 beam at PSI: a hybrid-type large acceptance channel for the generation of a high intensity surface-muon beam. Nucl. Instrum. Methods A595, 317–331 (2008)

    Article  ADS  Google Scholar 

  33. Morenzoni, E. et al. Generation of very slow polarized positive muons. Phys. Rev. Lett. 72, 2793–2796 (1994)

    Article  CAS  ADS  Google Scholar 

  34. Schwarz, K. & Mohn, P. Itinerant metamagnetism in YCO2 . J. Phys. F Met. Phys. 14, L129–L134 (1984)

    Article  CAS  ADS  Google Scholar 

  35. Kresse, G. & Furthmuller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996)

    Article  CAS  ADS  Google Scholar 

  36. Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996)

    Article  CAS  ADS  Google Scholar 

  37. Methfessel, M. & Paxton, A. T. High-precision sampling for Brillouin-zone integration in metals. Phys. Rev. B 40, 3616–3621 (1989)

    Article  CAS  ADS  Google Scholar 

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This work was supported by the Engineering and Physical Sciences Research Council through grants EP/K00512X/1, EP/K036408/1, EP/J01060X/1 and EP/I004483/1. Use of the N8 POLARIS (EPSRC EP/K000225/1), ARCHER (via the UKCP Consortium, EP/K013610/1), and the High Performance Computing (HPC) Wales facilities is acknowledged. Use of the National Synchrotron Light Source, Brookhaven National Laboratory, was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-98CH10886.

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F.A.M. and T.M. grew and characterized the samples, conducted the magnetometry and μSR, and contributed to the data analysis; G.T. performed and analysed the DFT simulations; W.D. grew and characterized the Cu–C60 multilayers; T.P., H.L., S.L. and M.F. contributed to the design, measurement and analysis of the μSR experiments; D.A.M. contributed to the TEM images and structural analysis; G.E.S. and D.A.A. performed the X-ray magnetic circular dichroism and X-ray absorption spectroscopy measurements; M.A., M.C.W., G.B. and B.J.H. contributed to the sample structure and measurement setup; and O.C. designed the study, analysed the data and wrote the manuscript. All authors discussed the results and commented on the manuscript.

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Correspondence to Oscar Cespedes.

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This file contains Supplementary Information sections 1-6, including Supplementary Figures 1-27, Supplementary Tables 1-9 and Supplementary References. (PDF 5170 kb)

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Ma’Mari, F., Moorsom, T., Teobaldi, G. et al. Beating the Stoner criterion using molecular interfaces. Nature 524, 69–73 (2015).

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