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

摘要

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 t_(Cu) 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 t_(Cu). SEM images show the appearance of Cu islands instead of continuous Cu layers. A minimum coercive field of 1.4 Oe is obtained for t_(Cu) =1.0 nm, while the ferromagnetic resonance line-width exhibited 200 Oe constant values for t_(Cu) between 0.7 and 2.1 nm. The effective magnetization increases with t_(Cu), possibly associated to the increase on Fe content as observed by EDX. The effective dynamic anisotropy behavior with t_(Cu) seems to be associated to the island structure observed in the films.