Observation of magnons in Mn2Au films by inelastic Brillouin and Raman light scattering

The intermetallic antiferromagnetic compound Mn2Au has been attracting considerable interest for antiferromagnetic spintronics due to its high Neel temperature and strong spin–orbit coupling. We report on the experimental investigation of the zero-wave number magnon frequencies in Mn2Au films using Brillouin and Raman inelastic light scattering techniques. The derived effective anisotropy field values are in close agreement with theoretical calculations. With the values of the anisotropy and exchange fields, the full magnon dispersion curves in Mn2Au were calculated. Due to the weak in-plane anisotropy, the k ∼ 0 frequency of the lower magnon branch, 121 GHz, is among the lowest for 3D antiferromagnets, suggesting that Mn2Au is a good candidate for realizing the generation of spin currents by antiferromagnetic resonance driven spin-pumping, as proposed theoretically.