TY - JOUR
T1 - Chiral magnetism and helimagnons in a pyrochlore antiferromagnet
AU - Choi, Eunsong
AU - Chern, Gia Wei
AU - Perkins, Natalia B.
PY - 2013/2/15
Y1 - 2013/2/15
N2 - Recent neutron scattering measurements on the spinel CdCr2O 4 revealed a rare example of helical magnetic order in geometrically frustrated pyrochlore antiferromagnet. The spin spiral characterized by an incommensurate wave vector Q=2π(0,δ,1) with δ≈0.09 is accompanied by a tetragonal distortion. Here we conduct a systematic study on the magnetic ground state resulting from the interplay between the Dzyaloshinskii-Moriya interaction and further neighbor exchange couplings, two of the most important mechanisms for stabilizing incommensurate spin orders. We compute the low-energy spin-wave spectrum based on a microscopic spin Hamiltonian and find a dispersion relation characteristic of the helimagnons. By numerically integrating the Landau-Lifshitz-Gilbert equation with realistic model parameters, an overall agreement between experiment and the numerical spectrum, lending further support to the view that a softened optical phonon triggers the magnetic transition and endows the lattice a chirality.
AB - Recent neutron scattering measurements on the spinel CdCr2O 4 revealed a rare example of helical magnetic order in geometrically frustrated pyrochlore antiferromagnet. The spin spiral characterized by an incommensurate wave vector Q=2π(0,δ,1) with δ≈0.09 is accompanied by a tetragonal distortion. Here we conduct a systematic study on the magnetic ground state resulting from the interplay between the Dzyaloshinskii-Moriya interaction and further neighbor exchange couplings, two of the most important mechanisms for stabilizing incommensurate spin orders. We compute the low-energy spin-wave spectrum based on a microscopic spin Hamiltonian and find a dispersion relation characteristic of the helimagnons. By numerically integrating the Landau-Lifshitz-Gilbert equation with realistic model parameters, an overall agreement between experiment and the numerical spectrum, lending further support to the view that a softened optical phonon triggers the magnetic transition and endows the lattice a chirality.
UR - http://www.scopus.com/inward/record.url?scp=84874141902&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84874141902&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.87.054418
DO - 10.1103/PhysRevB.87.054418
M3 - Article
AN - SCOPUS:84874141902
SN - 1098-0121
VL - 87
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 5
M1 - 054418
ER -