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Direct measurement of the electronic spin diffusion length in a fully functional organic spin valve by low-energy muon spin rotation

Nature Materials volume 8, pages 109–114 (2009)Cite this article

Abstract

Electronic devices that use the spin degree of freedom hold unique prospects for future technology. The performance of these ‘spintronic’ devices relies heavily on the efficient transfer of spin polarization across different layers and interfaces. This complex transfer process depends on individual material properties and also, most importantly, on the structural and electronic properties of the interfaces between the different materials and defects that are common to real devices. Knowledge of these factors is especially important for the relatively new field of organic spintronics, where there is a severe lack of suitable experimental techniques that can yield depth-resolved information about the spin polarization of charge carriers within buried layers of real devices. Here, we present a new depth-resolved technique for measuring the spin polarization of current-injected electrons in an organic spin valve and find the temperature dependence of the measured spin diffusion length is correlated with the device magnetoresistance.

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Figure 1: Schematic diagram of the experimental set-up.
Figure 2: Influence of spin injection on the μSR spectra.
Figure 3: Correlation between the direction of spin polarization of the injected carriers and the change in the μSR spectra.
Figure 4: Correlation between spin diffusion length and magnetoresistance.

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Acknowledgements

We acknowledge financial support from the Schweizer Nationalfonds (SNF) Nos 200021-111690 and 200020-119784 and the NCCR Materials with Novel Electronic Properties (MaNEP) programme. Experiments were carried out at the Swiss Muon Source, Paul Scherrer Institute, Villigen, Switzerland.

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Authors and Affiliations

  1. Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Chemin du Musée 3, CH-1700 Fribourg, Switzerland

    A. J. Drew, J. Hoppler, L. Schulz, V. K. Malik, A. Dubroka, K. W. Kim, H. Bouyanfif, F. Bourqui & C. Bernhard

  2. Department of Physics, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK

    A. J. Drew, P. Desai, P. Shakya, T. Kreouzis & W. P. Gillin

  3. Laboratory for Neutron Scattering, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland

    J. Hoppler

  4. ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Chilton, Didcot, OX11 0QX, UK

    F. L. Pratt

  5. Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland

    A. Suter, R. Scheuermann, G. J. Nieuwenhuys, T. Prokscha & E. Morenzoni

  6. Department of Engineering Materials, University of Sheffield, Mappin Street, Sheffield, S1 3JD, UK

    N. A. Morley

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Contributions

A.J.D. was responsible for project planning. A.J.D, J.H., L.S., F.L.P., A.S., N.A.M., V.K.M., A.D., K.W.K., H.B., R.S., G.J.N., T.P. and E.M. were responsible for the experimental measurements. A.J.D., J.H., L.S., F.L.P., A.S., T.K., W.P.G. and C.B. were responsible for the analysis and interpretation. A.J.D., P.D., P.S., T.K. and W.P.G. were responsible for the sample growth and characterization. The bespoke floating current source was designed, built and tested by A.J.D., A.S. and F.B.

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Correspondence to A. J. Drew.

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Drew, A., Hoppler, J., Schulz, L. 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). https://doi.org/10.1038/nmat2333

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