Nickel nanowires for planer microwave circuit applications and characterization

The dynamic properties of uniform one-dimensional arrays of high aspect ratio nickel nanowires have been studied by ferromagnetic resonance (FMR) technique at 24 GHz. The fundamental magnetic parameters such as spontaneous magnetization, gyromagnetic ratio (gamma), and magnetic anisotropies of the nanowires are derived from the angular variation of resonance field H-r(theta(H)) positions. The effective fields of the nanowire system were observed to decrease with increasing length of the nanowires. Further, the use of nanowires as a tunable stop-band notch filter in a coplanar waveguide geometry has been assessed. The stop-band frequency (f(r)) is observed to be tunable up to 14 GHz with an applied field (H) of up to 4 kOe. The kink in the f(r)(H) data gives the measure of the effective field (H-eff) of the nanowire system. The theoretical fitting of f(r)(H) data to resonance relation yields values of H-eff and gamma which are a little higher than the conventional FMR results. (C) 2007 American Vacuum Society.