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.

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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