Spin-wave directional anisotropies in antiferromagnetic Ba3NbFe3Si2 O14

C. Stock, R. D. Johnson, N. Giles-Donovan, M. Songvilay, J. A. Rodriguez-Rivera, N. Lee, X. Xu, P. G. Radaelli, L. C. Chapon, A. Bombardi, S. Cochran, Ch Niedermayer, A. Schneidewind, Z. Husges, Z. Lu, S. Meng, S. W. Cheong

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Abstract

Ba3NbFe3Si2O14 (langasite) is structurally and magnetically single-domain chiral with the magnetic helicity induced through competing symmetric exchange interactions. Using neutron scattering, we show that the spin waves in antiferromagnetic langasite display directional anisotropy. On applying a time-reversal symmetry breaking magnetic field along the c axis, the spin-wave energies differ when the sign is reversed for either the momentum transfer ±Q- or applied magnetic field ±μ0H. When the field is applied within the crystallographic ab plane, the spin-wave dispersion is directionally isotropic and symmetric in ±μ0H. However, a directional anisotropy is observed in the spin-wave intensity. We discuss this directional anisotropy in the dispersion in langasite in terms of a field-induced precession of the dynamic unit cell staggered magnetization resulting from a broken twofold symmetry. Directional anisotropy, often referred to as nonreciprocal responses, can occur in antiferromagnetic phases in the absence of the Dzyaloshinskii-Moriya interaction or other effects resulting from spin-orbit coupling.

Original languageEnglish (US)
Article number134429
JournalPhysical Review B
Volume100
Issue number13
DOIs
StatePublished - Oct 22 2019

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All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Stock, C., Johnson, R. D., Giles-Donovan, N., Songvilay, M., Rodriguez-Rivera, J. A., Lee, N., Xu, X., Radaelli, P. G., Chapon, L. C., Bombardi, A., Cochran, S., Niedermayer, C., Schneidewind, A., Husges, Z., Lu, Z., Meng, S., & Cheong, S. W. (2019). Spin-wave directional anisotropies in antiferromagnetic Ba3NbFe3Si2 O14. Physical Review B, 100(13), [134429]. https://doi.org/10.1103/PhysRevB.100.134429