The perpendicular magnetic anisotropy (PMA) and the interfacial Dzyaloshinskii-Moriya interaction (iDMI) are investigated in as grown and 300 °C annealed Co-based ultrathin systems. For this, Co films of various thicknesses (0.8 nm ⩽ t Co ⩽ 5.7 nm) were deposited by magnetron sputtering on thermally oxidized Si substrates using Pt, W, Ir, Ti, Ru and MgO buffer or/and capping layers. X-ray diffraction was used to investigate their structural properties and vibrating sample magnetometry (VSM) was used to determine the magnetic dead layer thickness and the magnetization at saturation (M s). VSM revealed that the M s for the Pt and the Ir buffered and capped films is the largest. Microstrip line ferromagnetic resonance (MS-FMR), used to extract the gyromagnetic ratio of the thicker Co films, revealed the existence of a second order PMA term, which is thickness dependent. Brillouin light scattering (BLS) in the Damon-Eshbach configuration was used to investigate the thickness dependence of the iDMI effective constant from the spin wave vector dependence of the frequency difference between Stokes and anti-Stokes lines. BLS and MS-FMR techniques were combined to measure the spin wave frequency variation as a function of the in-plane applied magnetic field (where the second order PMA contribution vanishes). The thickness dependence of the effective magnetization was then deduced and used to investigate PMA. For all the systems, PMA results from interface and volume contributions that we determined. The largest interface PMA constants were obtained for Pt- and Ir-based systems due to the electron hybridization of Co with these heavy metals having high spin orbit coupling. Annealing at 300 °C increases both the interface PMA and iDMI for the Pt/Co/MgO most probably due to de-mixing of interpenetrating oxygen atoms from the Co layer and the formation of a sharp Co/O interface.

中文翻译：

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生长和退火的 X/Co/Y 超薄系统中的垂直磁各向异性和界面 Dzyaloshinskii-Moriya 相互作用

在生长和 300°C 退火的 Co 基超薄系统中研究了垂直磁各向异性 (PMA) 和界面 Dzyaloshinskii-Moriya 相互作用 (iDMI)。为此，使用 Pt、W、Ir、Ti、Ru 和 MgO 缓冲层或/和覆盖层，通过磁控溅射在热氧化的 Si 衬底上沉积各种厚度的 Co 膜（0.8 nm ⩽ t Co ⩽ 5.7 nm）。X 射线衍射用于研究它们的结构特性，振动样品磁强计 (VSM) 用于确定磁死层厚度和饱和磁化强度 (M s)。VSM 显示 Pt 和 Ir 缓冲和封端薄膜的 M s 是最大的。用于提取较厚 Co 膜的旋磁比的微带线铁磁共振 (MS-FMR) 揭示了二阶 PMA 项的存在，这是厚度相关的。Damon-Eshbach 配置中的布里渊光散射 (BLS) 用于从斯托克斯线和反斯托克斯线之间的频率差的自旋波矢量依赖性研究 iDMI 有效常数的厚度依赖性。结合 BLS 和 MS-FMR 技术来测量自旋波频率变化作为面内施加磁场的函数（其中二阶 PMA 贡献消失）。然后推导出有效磁化的厚度依赖性并用于研究 PMA。对于所有系统，PMA 来自我们确定的界面和体积贡献。由于 Co 与这些具有高自旋轨道耦合的重金属的电子杂化，Pt 和 Ir 基系统获得了最大的界面 PMA 常数。