Magnons and electromagnons in a spin-lattice-coupled frustrated magnet CuFeO2 as seen via inelastic neutron scattering

Taro Nakajima, Azusa Suno, Setsuo Mitsuda, Noriki Terada, Shojiro Kimura, Koji Kaneko, Hiroki Yamauchi

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

We have investigated spin-wave excitations in a four-sublattice (4SL) magnetic ground state of a frustrated magnet CuFeO2, in which "electromagnon" (electric-field-active magnon) excitation has been discovered by recent terahertz time-domain spectroscopy. In a previous study, we identified two spin-wave branches in the 4SL phase by means of inelastic neutron scattering measurements under applied uniaxial pressure. In the present study, we have performed high-energy-resolution inelastic neutron-scattering measurements in the 4SL phase, resolving fine structures of the lower-energy spin-wave branch near the zone center. Taking account of the spin-driven lattice distortions in the 4SL phase, we have developed a model Hamiltonian to describe the spin-wave excitations. The determined Hamiltonian parameters have successfully reproduced the spin-wave dispersion relations and intensity maps obtained in the inelastic neutron-scattering measurements. The results of the spin-wave analysis have also revealed physical pictures of the magnon and electromagnon modes in the 4SL phase, suggesting that collinear and noncollinear characters of the two spin-wave modes are the keys to understanding the dynamical coupling between the spins and electric dipole moments in this system.

Original languageEnglish
Article number184401
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume84
Issue number18
DOIs
Publication statusPublished - 2011 Nov 4

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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