Dual-Band Noise Suppressors Based on Co/Au Multilayered Magnetic Nanowires

Co/Au multilayered magnetic nanowires with a diameter of 200 nm were electrodeposited into nanoporous anodic aluminum oxide (AAO) templates. Coplanar waveguide transmission lines were patterned on the AAO templates that were filled with the Co/Au nanowires. Noise suppressors based on pure Co and Au nanowires were also fabricated as references. The transmission coefficient S₂₁ of the device based on Co nanowires showed an absorption peak due to the loss of ferromagnetic resonance; S₂₁ of the device based on Au nanowires decreased linearly with increasing frequency due to the loss of eddy current. S₂₁ of the noise suppressors based on Co/Au multilayered nanowires showed a dual-band absorption phenomenon, because of the ferromagnetic resonance of the nanowires and the periodicity of the magnetic/nonmagnetic nanostructure. The frequencies of the two absorption peaks were 24-25 GHz and 36-38 GHz, which indicated that the working frequency of the microwave devices could be beyond 20 GHz.