Far-IR spectra of magnons, crystal field transitions, and phonons in hexagonal \textit{RE}MnO$_{3}$ (\textit{RE}=Er, Tm, Yb, Lu) single crystals

ORAL

Abstract

Far-IR spectra of hexagonal \textit{RE}MnO$_{3}$ (\textit{RE}=Er, Tm, Yb, Lu) single crystals have been studied between $T$=1.6 K and 300 K using transmission in high magnetic field and rotating analyzer ellipsometry. The symmetry of the IR optical phonons and their oscillator strengths were determined for compounds with different \textit{RE} ions. The temperature dependence of the phonon frequencies revealed a strong spin-phonon interaction in the temperature range below $T_{N}\sim $70 K. The effective g-factors have been determined for the AFM resonances and crystal field transitions using external magnetic fields up to 10 T. The frequency of the AFM resonances around 50 cm$^{-1}$ increases systematically with a decrease of the \textit{RE} ion radius. The observed effects are analyzed taking into account main magnetic interactions in the system including exchange of the Mn$^{3+}$ spins with \textit{RE}$^{3+}$ paramagnetic moments. The magnetic ordering of \textit{RE} ions was observed at low temperatures $T<$3.5 K and in strong magnetic fields.

*Work at NJIT and Rutgers was supported by DOE DE-FG02-07ER46382. Use of NSLS-BNL was supported by DOE DE-AC02-98CH10886.

–

Authors

  • E.C. Standard

    • Dept of Phys, NJIT, Newark NJ, USA

  • T.N. Stanislavchuk

    • Dept of Phys, NJIT, Newark NJ, USA

  • R. Basistyy

    • Dept of Phys, NJIT, Newark NJ, USA

  • A.A. Sirenko

    • Dept of Phys, NJIT, Newark NJ, USA

  • T.D. Kang

    • ReCFI, Dept of Phys and Astronomy, Seoul National U., Seoul, Korea

  • Nara Lee

    • Department of Physics and Astronomy and Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, USA
    • Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
    • Rutgers University
    • Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University
    • Rutgers Center for Emergent Materials and Dept of Phys and Astronomy, Rutgers U., NJ, USA
    • Department of Physics and Astronomy and Rutgers Center for emergent materials, Rutgers University, Piscataway, NJ 08854 USA

  • S-W. Cheong

    • Rutgers Center for Emergent Materials
    • Rutgers University
    • Department of Physics and Astronomy and Rutgers Center for Emergent Materials, Rutgers University, Piscataway, New Jersey 08854, USA
    • Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
    • Rutgers Center for Emergent Materials and Department of Physics and Astronomy, Rutgers University
    • Rutgers Center for Emergent Materials and Dept of Phys and Astronomy, Rutgers U., NJ, USA
    • Department of Physics and Astronomy and Rutgers Center for emergent materials, Rutgers University, Piscataway, NJ 08854 USA