Magnetic excitations in magnetic ferroelectrics, RMn$_2$O$_5$ (R = Y and Tb)

ORAL

Abstract

We report inelastic neutron scattering data obtained from powder and single crystal samples of magnetic ferroelectrics, RMn$_2$O$_5$ (R=Y and Tb). In these systems, magnetic moments are lying on the crystalline ab-plane, and the spontaneous electric polarization occurs along the b-axis. Our data shows that there are several different magnetic excitation modes of Mn spin waves upto 15 meV. The lowest energy excitation is the sliding mode of the moments in the ab-plane, called phason. We have performed linear spin wave calculations to reproduce our data including dispersions as well as polarizations of the spin wave excitations. Relation of the spin waves to electric polarization will be discussed.

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Authors

  • M. Kenzelmann

    • ETH/PSI

  • T.J. Sato

    • ISSP, University of Tokyo

  • S. Park

    • Department of Physics, Rutgers University

  • Seung-Hun Lee

    • Department of Physics, University of Virginia
    • University of Virginia

  • Jung Hwa Kim

    • Department of Physics, University of Virginia

  • Jae-Ho Chung

    • NIST Center for Neutron Research

  • Y. Qiu

    • NIST Center for Neutron Research

  • S-W. Cheong

    • Department of Physics, Rutgers University