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@ARTICLE{Kadlec:18474,
      author       = {Kadlec, C. and Goian, V. and Rushchanskii, K.Z. and Kuzel,
                      P. and Lezaic, M. and Kohn, K. and Pisarev, R.V. and Kamba,
                      S.},
      title        = {{T}erahertz and infrared spectroscopic evidence of
                      phonon-paramagnon coupling in hexagonal piezomagnetic
                      {YM}n{O}3},
      journal      = {Physical review / B},
      volume       = {84},
      number       = {17},
      issn         = {1098-0121},
      address      = {College Park, Md.},
      publisher    = {APS},
      reportid     = {PreJuSER-18474},
      pages        = {174120},
      year         = {2011},
      note         = {The authors thank M. Mostovoy for valuable discussions.
                      This work was supported by the Czech Science Foundation
                      (Project No. 202/09/0682), by AVOZ10100520, and by the Young
                      Investigators Group Program of the Helmholtz Association
                      (Contract VH-NG-409). The contribution of Ph.D. student V.G.
                      has been supported by Project Nos. 202/09/H041 and
                      SVV-2011-263303. R.V.P. acknowledges the support by the RFBR
                      (Project No. 09-02-00070). The support of the Julich
                      Supercomputing Center is gratefully acknowledged.},
      abstract     = {Terahertz and far-infrared electric and magnetic responses
                      of hexagonal piezomagnetic YMnO3 single crystals are
                      investigated. Antiferromagnetic resonance is observed in the
                      spectra of magnetic permeability mu(a) [H(omega) oriented
                      within the hexagonal plane] below the Neel temperature T-N.
                      This excitation softens from 41 to 32 cm(-1) upon heating
                      and finally disappears above T-N. An additional weak and
                      heavily-damped excitation is seen in the spectra of complex
                      dielectric permittivity epsilon(c) within the same frequency
                      range. This excitation contributes to the dielectric spectra
                      in both antiferromagnetic and paramagnetic phases. Its
                      oscillator strength significantly increases upon heating
                      toward room temperature, thus providing evidence of
                      piezomagnetic or higher-order couplings to polar phonons.
                      Other heavily-damped dielectric excitations are detected
                      near 100 cm(-1) in the paramagnetic phase in both epsilon(c)
                      and epsilon(a) spectra, and they exhibit similar temperature
                      behavior. These excitations appearing in the frequency range
                      of magnon branches well below polar phonons could remind
                      electromagnons, however their temperature dependence is
                      quite different. We have used density functional theory for
                      calculating phonon dispersion branches in the whole
                      Brillouin zone. A detailed analysis of these results and of
                      previously published magnon dispersion branches brought us
                      to the conclusion that the observed absorption bands stem
                      from phonon-phonon and phonon-paramagnon differential
                      absorption processes. The latter is enabled by strong
                      short-range in-plane spin correlations in the paramagnetic
                      phase.},
      keywords     = {J (WoSType)},
      cin          = {IAS-1 / PGI-1},
      ddc          = {530},
      cid          = {I:(DE-Juel1)IAS-1-20090406 / I:(DE-Juel1)PGI-1-20110106},
      pnm          = {Grundlagen für zukünftige Informationstechnologien},
      pid          = {G:(DE-Juel1)FUEK412},
      shelfmark    = {Physics, Condensed Matter},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000297294500007},
      doi          = {10.1103/PhysRevB.84.174120},
      url          = {https://juser.fz-juelich.de/record/18474},
}