Improvement of the interfacial Dzyaloshinskii-Moriya interaction by introducing a Ta buffer layer

\u3cp\u3eWe report systematic measurements of the interfacial Dzyaloshinskii-Moriya interaction (iDMI) by employing Brillouin light scattering in Pt/Co/AlO\u3csub\u3ex\u3c/sub\u3e and Ta/Pt/Co/AlO\u3csub\u3ex\u3c/sub\u3e structures. By introducing a tantalum buffer layer, the saturation magnetization and the interfacial perpendicular magnetic anisotropy are significantly improved due to the better interface between heavy metal and ferromagnetic layer. From the frequency shift between Stokes- and anti-Stokes spin-waves, we successively obtain considerably larger iDM energy densities (D\u3csub\u3emax\u3c/sub\u3e-=-1.65-±-0.13 mJ/m\u3csup\u3e2\u3c/sup\u3e at t\u3csub\u3eCo\u3c/sub\u3e-=-1.35-nm) upon adding the Ta buffer layer, despite the nominally identical interface materials. Moreover, the energy density shows an inverse proportionality with the Co layer thickness, which is the critical clue that the observed iDMI is indeed originating from the interface between the Pt and Co layers.\u3c/p\u3