Brillouin light scattering (BLS), complemented by ferromagnetic resonance (FMR) characterization, has been used for studying spin-wave (SW) propagation in $\mathrm{Py}\left(L\right)/\mathrm{Pt}\left(6\text{−}\mathrm{nm}\right)$ bilayers of various Py thicknesses $(4\mathrm{nm}\le L\le 10\mathrm{nm})$. The FMR measurements allowed determination of the pertinent magnetic parameters and revealed the existence of a normal surface anisotropy. A pronounced asymmetry of Damon-Eshbach (DE) wave frequencies has been evidenced by BLS. Therefore, the difference between Stokes and anti-Stokes DE frequencies has been measured versus SW wave number for all the samples. A detailed discussion about the origin of this frequency difference is reported, which concludes that this is due to interface Dzyaloshinskii-Moriya interaction (IDMI).

• Received 28 December 2014
• Revised 12 May 2015

DOI:https://doi.org/10.1103/PhysRevB.91.214409