Flexible tuning microwave permeability spectrum in ferromagnet/antiferromagnet_n exchange-biasedmultilayer stack structure

NiFe/IrMn/NiFe/IrMn₅/NiFe/IrMn₄/NiFe structured exchange-biased multilayer films are designed and prepared by magnetron sputtering. The static and the microwave magnetic properties are systematically investigated. The results reveal that adding partially pinned ferromagnetic layer can effectively broaden the ferromagnetic resonance linewidth toward low frequency domain. Moreover, a wideband multi-peak permeability spectrum with a 3.1-GHz linewidth is obtained by overlapping the spectra of different partially pinned ferromagnetic layers and antiferromagnet/ferromagnet/antiferromagnet_n stacks. Our results show that the linewidth of the sample can be feasibly tuned through controlling the proper exchange bias fields of different stacks. The designed multilayered thin films have potential application for a tunable wideband high frequency noise filter.