Abstract
The movement of magnetic domain walls can be used to build a device known as a shift register, which has applications in memory1 and logic circuits2,3. However, the application of magnetic domain wall shift registers has been hindered by geometrical restrictions, by randomness in domain wall displacement and by the need for high current densities or rotating magnetic fields. Here, we propose a new approach in which the energy landscape experienced by the domain walls is engineered to favour a unidirectional ratchet-like propagation. The domain walls are defined between domains with an out-of-plane (perpendicular) magnetization, which allows us to route domain walls along arbitrary in-plane paths using a time-varying applied magnetic field with fixed orientation. In addition, this ratchet-like motion causes the domain walls to lock to discrete positions along these paths, which is useful for digital devices. As a proof-of-principle experiment we demonstrate the continuous propagation of two domain walls along a closed-loop path in a platinum/cobalt/platinum strip.
Similar content being viewed by others
References
Parkin, S. S. P., Hayashi, M. & Thomas, L. Magnetic domain-wall racetrack memory. Science 320, 190–194 (2008).
Allwood, D. A. et al. Submicrometer ferromagnetic NOT gate and shift register. Science 296, 2003–2006 (2002).
Allwood, D. A. et al. Magnetic domain-wall logic. Science 309, 1688–1692 (2005).
Hayashi, N., Romankiw, L. & Krongelb, S. An analysis of a clear-view angelfish bubble-domain shift register. IEEE Trans. Magn. 8, 16–22 (1972).
Bobeck, A., Bonyhard, P. & Geusic, J. Magnetic bubbles: an emerging new memory technology. Proc. IEEE 63, 1176–1195 (1975).
You, C-Y., Sung, I. M. & Joe, B-K. Analytic expression for the temperature of the current-heated nanowire for the current-induced domain wall motion. Appl. Phys. Lett. 89, 222513 (2006).
Allwood, D. A., Xiong, G. & Cowburn, R. P. Domain wall diodes in ferromagnetic planar nanowires. Appl. Phys. Lett. 85, 2848–2850 (2004).
Himeno, A., Kasai, S. & Ono, T. Depinning fields of a magnetic domain wall from asymmetric notches. J. Appl. Phys. 99, 08G304 (2006).
Bryan, M. T., Schrefl, T. & Allwood, D. A. Symmetric and asymmetric domain wall diodes in magnetic nanowires. Appl. Phys. Lett. 91, 142502 (2007).
Pérez-Junquera, A. et al. Crossed-ratchet effects for magnetic domain wall motion. Phys. Rev. Lett. 100, 037203 (2008).
Yamaguchi, A., Kishimoto, T. & Miyajima, H. Asymmetric domain wall propagation in a giant magnetoresistance-type wire with oscillating interlayer exchange coupling. Appl. Phys. Express 3, 093004 (2010).
Piao, H-G., Choi, H-C., Shim, J-H., Kim, D-H. & You, C-Y. Ratchet effect of the domain wall by asymmetric magnetostatic potentials. Appl. Phys. Lett. 99, 192512 (2011).
O'Brien, L. et al. Tunable remote pinning of domain walls in magnetic nanowires. Phys. Rev. Lett. 106, 087204 (2011).
You, C-Y. Another method for domain wall movement by a nonuniform transverse magnetic field. Appl. Phys. Lett. 92, 152507 (2008).
Chappert, C. et al. Planar patterned magnetic media obtained by ion irradiation. Science 280, 1919–1922 (1998).
Hyndman, R. et al. Modification of Co/Pt multilayers by gallium irradiation. Part 1: The effect on structural and magnetic properties. J. Appl. Phys. 90, 3843–3849 (2001).
Lavrijsen, R., Franken, J. H., Kohlhepp, J. T., Swagten, H. J. M. & Koopmans, B. Controlled domain-wall injection in perpendicularly magnetized strips. Appl. Phys. Lett. 96, 222502 (2010).
Franken, J. H. et al. Precise control of domain wall injection and pinning using helium and gallium focused ion beams. J. Appl. Phys. 109, 07D504 (2011).
Franken, J. H., Hoeijmakers, M., Lavrijsen, R. & Swagten, H. J. M. Domain-wall pinning by local control of anisotropy in Pt/Co/Pt strips. J. Phys. Condens. Matter 24, 024216 (2012).
Lemerle, S. et al. Domain wall creep in an Ising ultrathin magnetic film. Phys. Rev. Lett. 80, 849 (1998).
Miron, I. M. et al. Perpendicular switching of a single ferromagnetic layer induced by in-plane current injection. Nature 476, 189–194 (2011).
Liu, L. et al. Spin-torque switching with the giant spin Hall effect of tantalum. Science 336, 555–558 (2012).
Schellekens, A. J., van den Brink, A., Franken, J. H., Swagten, H. J. M. & Koopmans, B. Electric-field control of domain wall motion in perpendicularly magnetized materials. Nature Commun. 3, 847 (2012).
Ehresmann, A. et al. Asymmetric magnetization reversal of stripe-patterned exchange bias layer systems for controlled magnetic particle transport. Adv. Mater. 23, 5568–5573 (2011).
Rapoport, E. & Beach, G. S. D. Dynamics of superparamagnetic microbead transport along magnetic nanotracks by magnetic domain walls. Appl. Phys. Lett. 100, 082401 (2012).
Metaxas, P. et al. Creep and flow regimes of magnetic domain-wall motion in ultrathin Pt/Co/Pt films with perpendicular anisotropy. Phys. Rev. Lett. 99, 217208 (2007).
Acknowledgements
This work is part of the research programme of the Foundation for Fundamental Research on Matter (FOM), which is part of the Netherlands Organisation for Scientific Research (NWO).
Author information
Authors and Affiliations
Contributions
J.H.F. devised the concept, designed and performed the experiments, performed the data analysis and prepared the manuscript. H.J.M.S. and B.K. accommodated the experiments, assisted in the analysis and commented on the final manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary information
Supplementary information (PDF 215 kb)
Supplementary movie
Supplementary movie (MOV 271 kb)
Rights and permissions
About this article
Cite this article
Franken, J., Swagten, H. & Koopmans, B. Shift registers based on magnetic domain wall ratchets with perpendicular anisotropy. Nature Nanotech 7, 499–503 (2012). https://doi.org/10.1038/nnano.2012.111
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nnano.2012.111
- Springer Nature Limited
This article is cited by
-
Position error-free control of magnetic domain-wall devices via spin-orbit torque modulation
Nature Communications (2023)
-
Planar-symmetry-breaking induced antisymmetric magnetoresistance in van der Waals ferromagnet Fe3GeTe2
Nano Research (2022)
-
Tailoring perpendicular magnetic anisotropy in Co/Pt multilayers by interface doping with ultrathin Fe layer
Rare Metals (2022)
-
Realization of macroscopic ratchet effect based on nonperiodic and uneven potentials
Scientific Reports (2021)
-
Thermally active nanoparticle clusters enslaved by engineered domain wall traps
Nature Communications (2021)