Impurity and boundary effects on magnetic monopole dynamics in spin ice

ORAL

Abstract

Using a SQUID magnetometer, we measure the time-dependent magnetic relaxation in Dy2Ti2O7 and find that it decays with a stretched exponential followed by a very slow long-time tail. In a Monte Carlo simulation governed by Metropolis dynamics we find that surface effects and a very low level of stuffed spins (0.30\%) - magnetic Dy ions substituted for non-magnetic Ti ions - can explain these signatures in the relaxation. We find that the additional spins trap the magnetic monopole excitations and provide the first example of how defects in a spin-ice material can obstruct the flow of monopoles.

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Authors

  • Jan Kycia

    • University of Waterloo
    • Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada

  • H.M. Revell

    • Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada

  • L.R. Yaraskavitch

    • Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada

  • J.D. Mason

    • Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada

  • K.A. Ross

    • Department of Physics and Astronomy, McMaster University, Hamilton, ON, L8S 4M1, Canada

  • H.M.L. Noad

    • Department of Physics and Astronomy, McMaster University, Hamilton, ON, L8S 4M1, Canada

  • H.A. Dabkowska

    • Department of Physics and Astronomy, McMaster University, Hamilton, ON, L8S 4M1, Canada

  • B.D. Gaulin

    • Department of Physics and Astronomy, McMaster University, Hamilton, ON, L8S 4M1, Canada

  • P. Henelius

    • KTH Royal Institute of Technology
    • Dept. of Theoretical Physics, Royal Institute of Technology, SE-106 91 Stockholm, Sweden