Magnetization Reversal of High Aspect Ratio Iron Nanowires Grown by Electrodeposition

Smooth and high aspect ratio Fe nanowire arrays with different diameters were prepared by a low cost electrodeposition method in nanoporous anodic aluminum oxide templates. The structural and magnetic properties of these nanowire arrays have been investigated. The nanowires have smooth surface and uniform diameters. Because of the very large length-to-diameter ratio ( ~ 250), the effective magnetic anisotropy is dominated by the shape anisotropy and the easy magnetization direction is oriented along the nanowire. Coercivity as a function of diameter indicates that the magnetization reversal takes place by curling mode. Whereas, the angular dependence of the coercivity doesn´t follow what is predicted by the curling mechanism, which may indicate that the magnetic reversal is also influenced by magnetic interactions between nanowires. The larger length and the smaller interpore distance induced stronger magnetic coupling between Fe nanowires. This dipolar interaction also reduces the coercivity and remanance squareness of the Fe nanowires.