Magnon-phonon coupling and two-magnon continuum in two-dimensional   triangular antiferromagnet CuCrO2
  CuCrO2 is a manifestation of a two-dimensional triangular antiferromagnet which exhibits an incommensurate noncollinear magnetic structure similar to a classical 120 degree ordering. Using the inelastic neutron scattering technique, direct evidence of a magnon-phonon coupling in CuCrO2 is revealed via the mixed magnon-phonon character of the excitation mode at 12.5 meV as well as a minimum at the zone boundary. A simple model Hamiltonian that incorporates an exchange striction type magnon-phonon coupling reproduces the observed features accurately. Also, continuum excitations originating from the interaction between quasiparticles are observed with strong intensity at the zone boundary. These features of the magnetic excitations are key to an understanding of the emergent excitations in noncollinear antiferromagnetic compounds. 
Kisoo Park, Joosung Oh, Jonathan C. Leiner, Jaehong Jeong, Kirrily C.   Rule, Manh Duc Le, Je-Geun Park
cond-mat.str-el cond-mat.mtrl-sci