High-frequency noise absorbing properties of nickel nanowire arrays prepared by DC electrodeposition

Nickel nanowire arrays are fabricated by electrochemical deposition in highly ordered nanosized pores in AAO (anodized aluminum oxide) templates, and their static and high-frequency noise absorbing properties have been investigated. Using the channelled AAO templates, a nickel nanowires array was fabricated by DC electrodeposition. Magnetic hysteresis was observed with a coercivity of 250- 300 Oe depending on the field orientation with respect to wire axis. Noise absorbing properties of the nickel nanowires array was measured using the microstrip line. S ₁₁ parameter increases with frequency and reaches a saturated value of about -10 dB. The reflected power (about 10%) is much less than that of nickel thin film (about -3 dB), which is due to higher in-plane electrical resistance of the nanowire array structure. S ₂₁ decreases with frequency and has a value of-3 dB at 2 GHz. The attenuation of conduction noise through microstrip line is due to the magnetic loss of individual nickel nanowires. Power absorption of the Ni nanowire array was estimated to be 50% in the frequency range above 2 GHz.