Microwave devices based on template-assisted NiFe nanowires: fabrication and characterization

Ferromagnetic nanowires have attracted extensive interest in the development of monolithic microwave integrated circuits for future microwave reciprocal and non-reciprocal devices. The aim of the present investigation is to explore the magnetization dynamics in NiFe nanowires using a field sweep ferromagnetic resonance (FMR) technique. We also fabricated microwave devices, such as phase shifters and notch filters, on these ferromagnetic nanowired (FMNW) substrates in microstrip transmission line geometry. 1D NiFe nanowires have been synthesized by a dc electrodeposition technique in anodic alumina oxide membranes. Detailed microstructural and magnetic properties of deposited nanowires were investigated. The FMR technique was used to study the dynamic properties in the frequency range from 15 to 25 GHz. The angular variation of resonance field H-r(theta(H)) yields the intrinsic parameters such as gyromagnetic ratio and effective field. The resonance field increases up to 7 kOe for changing the nanowire's axis from parallel to perpendicular direction. The stop-band frequency f(r) can be modulated up to 30 GHz and phase shifter showed a differential phase shift of 80 deg cm(-1) at higher frequency band with an external magnetic field of 5.3 kOe. It is observed that the superlative frequency which corresponds to the highest differential phase shift for NiFe nanowires improved considerably above 33 GHz.