Perpendicularly magnetized multilayers (MLs) with low magnetic damping and highly periodic stripe domains are promising materials for energy-efficient spintronic and magnonic devices. Here, we investigate the structure, together with the static and dynamic magnetic properties of a polycrystalline sputter-deposited ${[\mathrm{CoFeB}\left(0.3\mathrm{nm}\right)/\mathrm{Ni}\left(0.6\mathrm{nm}\right)]}_{50}$ ML and compare it to a ${[\mathrm{Co}\left(0.3\mathrm{nm}\right)/\mathrm{Ni}\left(0.6\mathrm{nm}\right)]}_{50}$ reference stack. Scanning transmission electron microscopy, supplemented by atomic force microscopy, reveals that using a CoFeB/Ni ML yields a more cohesive and denser grain microstructure than in the Co/Ni ML. Our structural results are corroborated by reciprocal-space x-ray reflectivity and x-ray diffraction, further indicating a smoother CoFeB/Ni ML with weakened crystallographic texture and reduced crystalline coherence lengths compared to the Co/Ni ML, while preserving the overall $\mathrm{fcc}\left(111\right)$ growth induced by the Pt seed layer. Vibrating sample magnetometry shows that the CoFeB/Ni ML exhibits weak perpendicular magnetic anisotropy (PMA), resulting in near-zero-remanence isotropic labyrinth stripe domains following out-of-plane saturation and parallel stripe domains after in-plane saturation, consistent with the absence of strong pinning sites. In contrast, the Co/Ni ML exhibits stronger PMA and more pinning-mediated, disordered domain patterns due to its more inhomogeneous microstructure. Field-dependent magnetic force microscopy demonstrates an evolution from labyrinth stripe to dense bubble domain states in the CoFeB/Ni ML, accompanied by a reduction in microscopic return-point memory of the remanent state. Broadband ferromagnetic resonance measurements further disclose a $25\%$ reduced Gilbert damping parameter $\alpha$ in the CoFeB/Ni ($\alpha =0.0147$) compared to the Co/Ni ML ($\alpha =0.0193$), along with a massive 370-fold reduction of the inhomogeneous linewidth broadening. The combined structural, magnetic, and dynamic results indicate that using CoFeB suppresses microstructure-induced magnetic inhomogeneities while staying in the PMA regime. These findings identify CoFeB/Ni MLs as a promising platform for perpendicular spintronic devices, combining low magnetic damping, which is beneficial for coherent magnetization dynamics and long-range magnonic signal propagation, with well-defined domain states.

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• Magnetic anisotropy
• Magnetic domains
• Magnetic multilayers
• Atomic force microscopy
• Ferromagnetic resonance
• Magnetic force microscopy
• Magnetization measurements
• Scanning transmission electron microscopy
• X-ray diffraction
• X-ray reflectivity