Proposals for novel spin-orbitronic logic and memory devices are often dependent on assumptions as to how materials with large spin-orbit and ferromagnets interact when in contact. Such interactions give rise to a host of novel phenomena, such as spin-orbit torques, chiral spin- structures and chiral spin-torques. These chiral properties are related to the anti-symmetric exchange, also referred to as the interfacial Dzyaloshinskii-Moriya interaction (DMI). For numerous phenomena, the relative strengths of the symmetric Heisenberg exchange and the DMI is of great importance. Here, we use spin-wave spectroscopy (Brillouin light scattering) to directly determine the DMI vector for a series of Ni80Fe20/Pt samples and compare the DMI and the independently measured Heisenberg exchange. We find that the Ni80Fe20- thickness-dependencies of the Heisenberg exchange and the DMI are strongly correlated, consistent with the notion that the anti-symmetric and symmetric exchange essentially share the same underlying physics, as was originally proposed by Moriya. While of significant fundamental importance, this result also leads us to a deeper understanding of DMI and how it could be optimized for spin-orbitronic applications.
magnetization dynamics, Dzyaloshinskii-Moriya-exchange, spintronics