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Current-induced magnetization reversal in nanopillars with perpendicular anisotropy

Nature Materials volume 5, pages 210–215 (2006)Cite this article

Abstract

Devices that show a magnetic anisotropy normal to the film surface hold great promise towards faster and smaller magnetic bits in data-storage applications. We describe an experimental demonstration of current-induced magnetic reversal of nanopillars with perpendicular anisotropy and high coercive fields. The best results are observed for Co/Ni multilayers, which have higher giant magnetoresistance values and spin-torque efficiencies than Co/Pt multilayers. The reference layers were designed to have significantly higher anisotropy allowing a complete current–field phase diagram of the free-layer reversal to be explored. The results are compared to micromagnetic modelling of the free layer that, depending on the bias current and applied field, details regions of irreversible magnetic switching, coherent and incoherent spin waves, or static non-uniform magnetization states. This ability to manipulate high-anisotropy magnetic elements could prove useful for a range of spintronic applications.

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Figure 1: Schematic representation of patterned Co/Ni samples.
Figure 2: Transport measurements of the 50×100 nm2 Co/Ni sample.
Figure 3: Experimentally determined IB–H phase diagram for the 50×100 nm2 Co/Ni sample showing the parallel or antiparallel states where each symbol corresponds to a distinct change in the resistance.
Figure 4: Transport measurements of the 50×100 nm2 Co/Ni sample.
Figure 5: Theoretically derived phase diagram for the switching of the free layer with the magnetization of the reference layer pointing down.

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Acknowledgements

We would like to thank Y. Lemaho, Y. Henry and D. Lacour for assistance in transport measurement and J. Sun for fruitful discussion.

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Authors and Affiliations

  1. Hitachi Global Storage Technologies, San Jose Research Center, 650 Harry Road, San Jose, California, 95120, USA

    S. Mangin, D. Ravelosona, J. A. Katine, M. J. Carey, B. D. Terris & Eric E. Fullerton

  2. Laboratoire de Physique de Matériaux, UMR CNRS 7556, U.H.P.-Nancy I, B.P. 239, F-54506, Vandoeuvre cedex, France

    S. Mangin

  3. Institut d’Electronique Fondamentale, UMR CNRS 8622, Université Paris Sud, 91405, Orsay Cedex, France

    D. Ravelosona

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Correspondence to Eric E. Fullerton.

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Mangin, S., Ravelosona, D., Katine, J. et al. Current-induced magnetization reversal in nanopillars with perpendicular anisotropy. Nature Mater 5, 210–215 (2006). https://doi.org/10.1038/nmat1595

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