Magnetoimpedance properties of CoNbZr, multilayer CoNbZr/Au and multilayer NiFe/Au thin films
Indujan Sivanesarajah (Saarland University)
L. Abelmann (TU Delft - Bio-Electronics)
Uwe Hartmann (Saarland University)
More Info
expand_more
Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.
Abstract
Thin-film giant magnetoimpedance (GMI) structures are promising candidates for high-frequency magnetic sensing, with their performance governed by the interplay of electronic transport, magnetic softness, and ferromagnetic resonance (FMR). Optimisation therefore requires a comprehensive understanding of the properties of soft magnetic materials. This study investigates the structural, electric, magnetic, and GMI properties of sputtered amorphous CoNbZr single layers, amorphous CoNbZr/Au multilayers, and crystalline NiFe/Au multilayers. GMI measurements reveal distinct FMR frequencies of 1.4 GHz (CoNbZr), 0.7 GHz (CoNbZr/Au), and 0.5 GHz (NiFe/Au). Introducing Au interlayers into CoNbZr lowers the FMR frequency by 50% and enhances the maximum GMI ratio by a comparable margin relative to the single-layer film. At 1.8 GHz, the highest GMI performance is observed in a 20μm×5000μm CoNbZr/Au strip, yielding 300% with a sensitivity of 249%/kAm−1. Under identical conditions, single-layer CoNbZr reaches 180% (169%/kAm−1) and NiFe/Au 280% (183%/kAm−1), confirming the superior response of the CoNbZr/Au multilayer. These improvements are attributed to differences in in-plane demagnetising factors and saturation magnetisations, providing design guidelines for the development of resonant GHz-range GMI sensors.
help_outline