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

Published

April 8, 2020

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

Pub Type

Journals

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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 Cu₂OSeO₃: A Coarse-Grained Approach, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=929864 (Accessed October 14, 2024)