Ballistic low-temperature magnon heat conduction in the helimagnetic insulator Cu$_2$OSeO$_3$

ORAL

Abstract

We report on the observation of magnon thermal conductivities $\kappa_m\sim 80$~W/mK near $T=5$~K in single crystals of the helimagnetic insulator Cu$_2$OSeO$_3$, exceeding those observed previously in any other ferro- or ferrimagnet by almost two orders of magnitude. Distinguished in applied magnetic field, both magnon and phonon thermal conductivities exhibit ballistic behavior below 1K, with mean free paths limited by specimen boundaries. Changes in $\kappa_m$ through the helical-conical and conical-collinear spin-phase transitions with increasing applied field will also be discussed.

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Authors

  • Narayan Prasai

    Department of Physics, University of Miami, University of Miami

  • Artem Akopyan

    University of Miami

  • Sunxiang Huang

    University of Miami

  • Joshua L. Cohn

    Department of Physics, University of Miami, University of Miami

  • Benjamin Trump

    Johns Hopkins University

  • Guy G. Marcus

    IQM at JHU, Johns Hopkins University

  • Tyrel McQueen

    Johns Hopkins University, Johns Hopkins Univ, Johns Hopkins University, Baltimore, USA