AC electrodeposition frequency dependence of composition and magnetic properties of Fe-Co nanowire arrays

Fe-Co alloy nanowire arrays with the interwire distance of about 50 nm and the wire diameter of about 22 nm were fabricated by alternating current electrodeposition at different frequencies into anodic aluminum oxide templates. The influences of the deposition frequency on the composition, crystalline structure and magnetic properties of the arrays were studied in detail. It was found that the deposition frequency for the Fe-Co alloy nanowire arrays has an optimal range of 5~350 Hz. For the arrays prepared within this range, the deposition frequency has no obvious influence on their crystalline structure, while it does affect the arrays composition and magnetic properties. The variations for the nanowires saturation magnetization and the magnetostatic interaction between nanowires were employed to explain the change in the arrays magnetic properties with the deposition frequency qualitatively. After annealing in hydrogen atmosphere, all the arrays fabricated within the optimal frequency range have fairly good magnetic properties. Their coercivities and squarenesses are higher than 3512 kOe and 0939, respectively. The array deposited at 50 Hz possesses the comparatively best hard magnetic performance. The thermomagnetic analysis indicates that its Curie temperature is about 630 ℃.