Rotationally induced magnetic chirality in clusters of single-domain permalloy islands and gapped nanorings

ORAL

Abstract

We have studied magnetic moment configurations of clusters of single-domain ferromagnetic islands in different geometries.\footnote{J. Li , S. Zhang, J. Bartell, C. Nisoli, X. Ke, Paul E. Lammert, Vincent H. Crespi, and P. Schiffer, Physical Review B \textbf{82}, 134407 (2010).} The magnetic moments of these clusters are imaged by MFM after rotational demagnetization, following our previous protocols.\footnote{R. F. Wang, C. Nisoli, R. S. Freitas, J. Li, W. McConville, B. J. Cooley, M. S. Lund, N. Samarth, C. Leighton, V. H. Crespi, P. Schiffer, Nature \textbf{439}, 303 (2006).} We observed that two types of the clusters showed a significant imbalance of their two-fold degenerate ground states after demagnetization, and this inequality is correlated to the rotational direction of the demagnetization. A similar imbalance was also found in nano-scale rings with a small gap: the chirality of their magnetic state can be precisely controlled by the rotational direction during demagnetization.

*We acknowledge the financial support from DOE and Army Research Office. We are grateful to Prof. Chris Leighton and Mike Erickson for assistance with sample preparation.

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Authors

  • Sheng Zhang

    • Pennsylvania State University
    • Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802
    • Penn State University

  • Jie Li

    • Pennsylvania State University
    • Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802
    • Penn State University

  • Jason Bartell

    • Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802
    • Penn State University

  • Paul Lammert

    • Pennsylvania State University
    • Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802
    • Penn State University

  • Vincent Crespi

    • Penn State University
    • Pennsylvania State University
    • Department of Physics, Penn State University
    • Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802

  • Peter Schiffer

    • The Pennsylvania State University, University Park, PA
    • Pennsylvania State University
    • Department of Physics and Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
    • Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, PA 16802
    • Penn State University