Fe3O4 nanowire arrays synthesized in AAO templates

Fe3O4 nanowire arrays with an average diameter of about 120 nm and lengths up to 8 mum were synthesized in anodic aluminum oxide templates through electrodepositing and heat treating a precursor beta-FeOOH. The nanowires have a polycrystalline spinel structure with a = 8.31 Angstrom and each nanowire is composed of fine particles. Influences of the sintering and the reducing temperatures on the products have been demonstrated by Mossbauer spectra and X-ray diffraction. It was found that high-coercivity nanowires can be obtained when the precursor was sintered at 500 degreesC in air and then reduced at 325 degreesC in H-2, Hysteresis loops measured at room temperature show a clear perpendicular magnetic anisotropy.