Permalloy–FeMn exchange-biased multilayers grown on flexible substrates for microwave applications

Permalloy–FeMn multilayers deposited onto flexible substrates oriented for wide-band absorber applications were fabricated using RF sputtering deposition. The ferromagnetic resonance (FMR) frequency was tuned by changing the thickness of the Permalloy layers. Plural FMR frequencies appeared in the multilayer film due to the difference in exchange couple energies at their interfaces. A multilayer thin film with varying thickness of Permalloy layers was also fabricated with the properties of a wide-band absorber. Its range of 1–4 GHz (the absorption width where the reflection loss is less than 10 dB) appears promising for future applications.