CoFe2O4 nanowire arrays prepared by template-electrodeposition method and further oxidization

By electrodeposition method and further oxidization, CoFe2O4 nanowire arrays within anodic aluminum oxide (AAO) templates were obtained. The XRD result proved that the phase structure of the nanowires is cubic spinel-type, and they exhibit no preferred crystallite orientation. The TEM images showed that, the CoFe2 nanowires electrodeposited within the templates are loose, while they transformed into compact CoFe2O4 nanowires by thermal annealing in open air. When the pore widening time is 40 min, the coercivity of the nanowire arrays reaches the maximum, 1.9 kOe, with the applied field parallel to the nanowires. With further increasing of the pore widening time, the coercivity decreases. When the applied field is vertical to the nanowires, the coercivity decreases with increasing the pore widening time, monotonously. The squareness ratio of the nanowire arrays with parallel applied field decreases from 0.48 to 0.42, monotonously, whereas the squareness ratio with vertical applied field increases from 0.48 to 0.52. (c) 2006 Elsevier B.V. All rights reserved.