Ir and Pt thickness dependences of the interfacial Dzyaloshinskii-Moriya interaction (iDMI), the perpendicular magnetic anisotropy (PMA), and the damping in Co-based systems grown by sputtering on Si substrates, using Ir or Pt under or overlayer of variable thickness ($0\le t_{\mathrm{Pt}}\le 3.5\mathrm{nm}$ and $0\le t_{\mathrm{Ir}}\le 1.5\mathrm{nm}$), were investigated using Brillouin light scattering. Vibrating sample magnetometry measurements revealed a significant decrease of the areal magnetic moment at saturation as the thickness $t_{\mathrm{Pt}}$ or $t_{\mathrm{Ir}}$ of the overlayer increases, most likely due to the increasing intermixing. The intermixing, found to be negligible for Ir and Pt underlayers, is stronger for Ir than Pt overlayers. Damping measurements for Pt-based systems allowed us to conclude with the strong spin-pumping contribution. The analysis of the $t_{\mathrm{Pt}}$ dependence of damping, within the spin-pumping model, allowed us to determine the spin-diffusion length of Pt, found to be greater when Pt is used as an underlayer. The $t_{\mathrm{Pt}}$ dependence of the effective PMA and iDMI constants, for which similar trends to that of damping were observed, were qualitatively analyzed to separate the contribution of each interface with Co. It was found that these constants are stronger when Co is grown on Pt, most probably due to weaker intermixing at the Pt/Co interface. Linear dependence of damping vs the PMA effective constant was evidenced, confirming their relationship with spin-orbit coupling (SOC). A linear variation of the PMA effective constant vs the iDMI constant was observed in systems using Pt underlayer, whereas quadratic or linear correlations are possible when Pt is used as an overlayer, probably due to change of the interface SOC by the strong intermixing at the Co/Pt interface. The qualitative analysis of the Ir thickness dependence of iDMI and PMA constants revealed a significant (weak) contribution of the Ir/Co interface to PMA (iDMI). The surface iDMI constant of the Co/Ir interface was estimated to be 0.4 ± 0.1 pJ/m, which confirms the similar iDMI sign of Co/Ir and Co/Pt interfaces.

中文翻译：

---

Co基系统中界面 Dzyaloshinskii-Moriya 相互作用、垂直磁各向异性和阻尼对 Pt 和 Ir 层厚度的依赖性

界面 Dzyaloshinskii-Moriya 相互作用 (iDMI)、垂直磁各向异性 (PMA) 和 Co 基系统中的 Ir 和 Pt 厚度依赖性，这些系统通过在 Si 衬底上溅射生长，使用 Ir 或 Pt 下层或上层可变厚度（$0\le {吨}_{铂}\le 3.5\mathrm{纳米}$ 和 $0\le {吨}_{\mathrm{红外线}}\le 1.5\mathrm{纳米}$)，使用布里渊光散射进行研究。振动样品磁力测量显示饱和时的面积磁矩随着厚度的增加而显着降低${吨}_{铂}$ 或者 ${吨}_{\mathrm{红外线}}$覆盖层的数量增加，很可能是由于混合增加。发现 Ir 和 Pt 底层的混合可以忽略不计，Ir 的混合比 Pt 覆盖层更强。基于 Pt 的系统的阻尼测量使我们能够得出强大的自旋泵浦贡献的结论。的分析${吨}_{铂}$在自旋泵浦模型中，阻尼的依赖性使我们能够确定 Pt 的自旋扩散长度，当 Pt 用作底层时，发现该长度更大。这${吨}_{铂}$对观察到与阻尼相似的趋势的有效 PMA 和 iDMI 常数的依赖性进行了定性分析，以分离每个界面与 Co 的贡献。发现当 Co 在 Pt 上生长时，这些常数更强，最有可能由于 Pt/Co 界面处较弱的混合。阻尼与 PMA 有效常数的线性相关性得到证实，证实了它们与自旋轨道耦合 (SOC) 的关系。在使用 Pt 底层的系统中观察到 PMA 有效常数与 iDMI 常数的线性变化，而当 Pt 用作覆盖层时，可能存在二次或线性相关，这可能是由于 Co 处的强混合导致界面 SOC 发生变化/Pt 接口。iDMI 和 PMA 常数的 Ir 厚度依赖性的定性分析揭示了 Ir/Co 界面对 PMA (iDMI) 的显着（弱）贡献。Co/Ir 界面的表面 iDMI 常数估计为 0.4 ± 0.1 pJ/m，这证实了 Co/Ir 和 Co/Pt 界面的相似 iDMI 符号。