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Low-Energy Magnons in the Chiral Ferrimagnet Cu2OSeO3: A Coarse-Grained Approach

Published

Author(s)

Yi Luo, G. G. Marcus, Benjamin Trump, J. Kindervater, M. B. Stone, Jose Rodriguez Rivera, Yiming Qiu, T. M. McQueen, O. Tchernyshyov, Collin L. Broholm

Abstract

We report a comprehensive neutron scattering study of low energy magnetic excitations in the breathing pyrochlore helimagnetic Cu2OSeO3. Fully documenting the four lowest energy magnetic modes that leave the ferrimagnetic configuration of the "strong tetrahedra" intact (< 13 meV), we find gapless quadratic dispersion at the Γ point for energies above 0.2 meV, two doublets separated by 1.6(2) meV at the R point, and a bounded continuum at the X point. Our constrained rigid spin cluster model relates these features to Dzyaloshinskii-Moriya(DM) interactions and the incommensurate helical ground state. Combining conventional spin wave theory with a spin cluster form-factor accurately reproduces the measured equal time structure factor through multiple Brillouin zones. An effective spin Hamiltonian describing the complex anisotropic inter-cluster interactions is obtained.
Citation
Physical Review B
Volume
101
Issue
14

Keywords

magnon, chiral ferrimagnet, neutron scattering

Citation

Luo, Y. , Marcus, G. , Trump, B. , Kindervater, J. , Stone, M. , Rodriguez Rivera, J. , Qiu, Y. , McQueen, T. , Tchernyshyov, O. and Broholm, C. (2020), Low-Energy Magnons in the Chiral Ferrimagnet Cu<sub>2</sub>OSeO<sub>3</sub>: A Coarse-Grained Approach, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=929864 (Accessed April 26, 2024)
Created April 7, 2020, Updated October 12, 2021