Indexed on: 01 Sep '11Published on: 01 Sep '11Published in: Journal of Superconductivity and Novel Magnetism
Highly ordered nanowire arrays of NiFe2O4 spinel with a high aspect ratio were fabricated by sol–gel method associated with anodic aluminum oxide (AAO) templates. The preparation of nanowires was carried out by sol–gel method using nickel nitrate, ferric nitrate and citric acid. The molar proportion of nickel nitrate to ferric nitrate and citric acid was 1:2:3. The suction with 0.1 mbar vacuum was used to draw the gel into the AAO nanochannels. The results showed that the lowest annealing temperature is around 600 °C to obtain the single-phase nanostructured NiFe2O4. The NiFe2O4 nanowires were also uniform and parallel. TEM pictures determined the diameter size of the nanowires of about 100 nm. The magnetic results also showed that the wires have an easy axis of magnetization along their length and they are fully saturated in a field of 7 kOe. It seems that this material could be a good candidate for high perpendicular magnetic storage devices.