Microwave absorption of electroplated NiFeCu/Cu multilayers deposited directly on Si (100) substrates

• NiFeCu/Cu multilayers were deposited directly on Si (100) substrates.
• Microwave absorption and FMR-linewidths were studied by broadband FMR.
• Samples presented low coercive fields and low saturation fields.
• Cu thickness changed the effective magnetization and effective dynamic anisotropies.

We study the magnetic properties and broadband microwave absorption of electroplated NiFeCu/Cu multilayered thin films deposited directly on Si (100) substrates. We produced samples with 20 nm thick NiFeCu layers and Cu layer thickness tCutCu in the range 0–2.8 nm. Structural properties were studied by grazing incidence X-ray diffraction (GIXRD), while the composition and morphological aspects were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). GIXRD confirmed the cubic face centered FCC phase of NiFeCu with all diffraction peaks drifting toward lower angles with tCutCu. SEM images show the appearance of Cu islands instead of continuous Cu layers. A minimum coercive field of 1.4 Oe is obtained for tCu=1.0nm, while the ferromagnetic resonance linewidth exhibited 200 Oe constant values for tCutCu between 0.7 and 2.1 nm. The effective magnetization increases with tCutCu, possibly associated to the increase on Fe content as observed by EDX. The effective dynamic anisotropy behavior with tCutCu seems to be associated to the island structure observed in the films.