Mn – Ir ∕ Fe – Si exchange-coupled multilayer film with plural ferromagnetic resonance absorptions for wideband noise filter

Abstract

Mn-Ir/Fe-Si exchange-coupled multilayer films for a wideband and GHz band noise filter are fabricated and evaluated. The Fe-Si film has characteristics of high saturation magnetization of 19 kG, low magnetostriction of the order of 10 -6 and high resistivity of 73 µΩ･cm. When the exchange bias magnetic field is introduced to the Fe-Si layers by the effect of Mn-Ir/Fe-Si exchange-coupling, the ferromagnetic resonance (FMR) frequency of the multilayer film is higher than the natural frequency of the single Fe-Si film. In addition, the multilayer film which has different thickness in each Fe-Si layer has plural FMR frequencies. The multiple FMR frequency gives the films characteristic of wideband energy absorption. The FMR absorption bandwidth of the multilayer film which has three FMR frequencies is about three times wider than that of single FMR film. Therefore, the multilayer film with plural FMR frequencies has an advantage in wideband noise absorption and will be useful material for the wideband and GHz frequency range noise filterings.