Quantifying the interfacial dzyaloshinskii-moriya interactions from spin-waves

We determined the magnitude of the Dzyaloshinskii-Moriya interaction for a thickness series of Ni
₈₀
Fe
₂₀
/Pt samples from Brillouin Light Scattering (BLS) measurements . The Dzyaloshinskii-Moriya interaction is an anti-symmetric exchange mechanism and is for two neighboring spins S
_i
and S
_j
given by HDMI=-D.(S
_i
×S
_j
), where D is the Dzyaloshinskii-Moriya interaction vector . In systems with interfacial Dzyaloshinskii-Moriya interaction D is perpendicular to the interface normal and the vector connecting S
_i
and S
_j
. The symmetric Heisenberg exchange is given by H=-J
_ij
(S
_i
.S
_j
), where J is the exchange integral . T . Moriya showed for magnetic oxides and A . Fert and P . Levy for metallic spin-glasses that the anti-symmetric Dzyaloshinskii-Moriya interaction and the symmetric Heisenberg exchange share the same underlying physics and are both proportional to each other .