Uniaxial magnetization reversal process in electrodeposited high-density iron nanowire arrays with ultra-large aspect ratio

Abstract

In this study, magnetization reversal modes of iron nanowire arrays with large aspect ratios were investigated by Shtrikman’s micromagnetic theory. The iron nanowire arrays were potentiostatically electrodeposited into anodized aluminum oxide nanochannels with average diameters, Dp, of ca. 33 nm, 52 nm, 67 nm, and 85 nm. The growth rate of the iron nanowires was ca. 105 nm s−1 at the cathode potential of −1.2 V (vs. an Ag/AgCl reference), and the axial length, Lw, reached up to ca. 60 µm. Maximum aspect ratio, Lw/Dw of the iron nanowires was found to be ca. 1800, and the axial direction coincided with 〈1 1 0〉 direction of the bcc-Fe crystal structure. The effect of the average diameter size on the coercivity of iron nanowire arrays corresponded well to the theoretical estimate, which was calculated by the magnetization curling mode in Shtrikman’s micromagnetic theory. As the average diameter of the iron nanowires was decreased, coercivity and squareness of the nanowire arrays increased up to 1.63 kOe and 0.87, respectively.