Size bistability in magnetoelectric cycloids

ORAL

Abstract

Most multiferroic materials with coexisting ferroelectric and magnetic order exhibit cycloidal antiferromagnetism with wavelength much larger than lattice spacing. The prototypical example is bismuth ferrite (BiFeO3 or BFO), a room-temperature multiferroic considered for a number of technological applications, including magnetic memories with electric-write capability. While most applications requires small sizes such as nanoparticles, little is known about the state of these materials when their sizes are comparable to the cycloid wavelength. This work describes a theory of cycloid magnetism in nanoparticles. It is argued that magnetic anisotropy close to the surface has a huge impact on the ground state cycloidal wavevector, leading to several observable consequences. For certain sizes the cycloidal wavevector is bistable, an effect that may be exploited in the design of novel memory devices.

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Presenters

  • Marc Allen

    Department of Physics and Astronomy, University of Victoria, BC, Canada

Authors

  • Marc Allen

    Department of Physics and Astronomy, University of Victoria, BC, Canada

  • Ian Aupiais

    Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot

  • Maximilien Cazayous

    Laboratoire Matériaux et Phénomènes Quantiques, Université Paris Diderot, Laboratoire Matériaux et Phénomènes Quantiques, UMR 7162 CNRS, Université Paris Diderot

  • Rogério de Sousa

    Dept. of Physics and Astronomy, University of Victoria, BC, Canada, Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, Canada, Department of Physics and Astronomy, University of Victoria, Canada, Department of Physics and Astronomy, University of Victoria, BC, Canada