Ultrawideband microwave noise filter: Hybrid antiferromagnet/ferromagnet exchange-coupled multilayers

Abstract

Hybrid multilayers of [FeNi–FeMn]N/[MnIr–FeCo]N deposited onto flexible substrates oriented for wideband noise filters were fabricated using rf sputtering deposition. By combining the two types of multilayers with various thicknesses, where FeNi–FeMn is designed for the low frequency range and MnIr–FeCo for the high frequency range, one can realize a hybrid thin film for wideband noise filters. Its broad range from 1.5 to 7 GHz (the absorption width where the reflection loss is less than −10 dB) makes this hybrid thin film promising for future applications.

Soft magnetic properties and high frequency characteristics of FeM (M = B, Hf, Zr) and pure Fe films fabricated by oblique deposition

“…3b, where magnetic anisotropy field H k and coercivity H ce along easy axis were plotted as a function of oblique angles. Both of the IPUMA field H k and coercivity H ce increased firstly and then decreased with the increase in oblique angle, which was consistent with previous researches [20]. The magnetic anisotropy existed due to columnar growth at large-oblique-angle substrate.…”

“…Many attempts have been made to tune the microwave properties by exploiting the extra anisotropy induced by patterning the film [15], using exchange bias effect between ferromagnet and antiferromagnet [16][17][18][19][20][21][22], laminating multilayered thin films [23], gradient-composition sputtering [24], by doping with other elements [25] or oblique deposition technique [26]. Among these, element doping and oblique deposition techniques are quite simple and effective methods for improving the microwave characteristics of soft-magnetic thin films [27].…”

Ultra-high ferromagnetic resonance frequency in exchange-biased system

“…There are several methods to increase the uniaxial anisotropy field such as patterning thin films [3], field annealing [4], oblique deposition [5,6], employing multilayerstructure films [7], and using exchange bias effect [9][10][11][12][13][14]. When using exchange bias to obtain high FMR frequency, most groups tried to decrease the ferromagnetic (FM) thickness while keeping the antiferromagnetic (AF) thick enough so as to get the largest exchange bias field (H E ) [9][10][11][12][13][14]. This method however has a drawback that the filling ratio (t FM /t AF ) is small causing a reduction of effective permeability since the thick AF layer does not contribute to the total permeability of the film [11].…”

Magnetic characteristics of a high-layer-number NiFe/FeMn multilayer

“…Tailoring these thicknesses within a multilayer can give rise to a range in the absorption frequencies and has applications in broadband microwave shielding. 8 The total effective field acting on an FM film affects the associated ferromagnetic resonance (FMR), and can create sizeable shifts in the resonance frequency. 9,10 FMR has been used to study exchange bias as an effective bulk field in a number of different systems.…”