Fabrication and Study of the Magnetic Properties of (Fe₃₀Co₇₀)_100-xZn_xNanowire Arrays

Abstract

(Fe30Co70)100−xZnx (0 ≤ x ≤ 10) nanowires with diameters of ≈37 nm have been fabricated by AC electrodeposition into pores of anodized aluminum oxide (AAO) templates. The Fe30Co70 and Zn contents of the nanowires have been adjusted by varying the ratio of Fe30Co70 and Zn ion concentrations in the electrolyte. The eect of the Zn content and annealing on the magnetic properties (e.g., coercivity and squareness) of nanowires arrays have been investigated using X-ray diraction, scanning electron microscopy, and alternating gradient force magnetometer. X-ray diraction patterns reveal that an increase in the concentration of Zn ions of the electrolyte results in signicant reduction in coercivity and squareness. It was found that the magnetic properties of nanowires can be signicantly improved by appropriate annealing process. The highest values for coercivity (2670 Oe) and squareness (0.99) have been obtained for nanowires electrodeposited using 95/5 and 98/2 Fe30Co70:Zn concentrations at annealing temperatures of 575• C and 550• C, respectively.

Magnetic Vortex Domain Wall Observation on Polycrystalline Imperfect Iron−Cobalt Alloy Nanowires Growing on 1050 Aluminum

“…Several authors have reported in the literature the use of X-ray diffraction in the BraggÀBrentano mode to study the crystalline structure of the FeCo Nw arrays growing in alumina templates and using aluminum as the substrate with lengths smaller than 10 μm. [26,28,31,35,46,52,53,[64][65][66] However, other authors reported that when XRD measurements were done in the BraggÀBrentano mode for Nws shorter than 10 μm after removal of the aluminum substrate and replaced with a metallic film (Au and/or Cu) as work electrode, these films deposited on the backside of the nanoporous alumina template were detected in the diffractograms. [17,49,67,68] For these reasons, we consider that the structural analysis of FeCo Nw arrays in alumina templates on aluminum substrates with lengths shorter than 10 μm must be done in the grazing-incidence X-ray diffraction (GIXRD) mode instead of the XRD BraggÀBrentano mode.…”

“…This result suggests that the electrodeposited Nws are stressed [67] due to the rapid deposition of Fe 2þ and Co 2þ into the nanopores. [31,34] Moreover, the confined template-assisted growth forces to lodge atoms in the nanocavities and yields structural defects. [72] The granular structure of the Nws was analyzed with TEM images, as shown in Figure 5b.…”

“…[23] The use of PAA templates for the fabrication of Fe x Co 100Àx Nws is widely reported as it can achieve diameters from 10 nm [24] up to 300 nm; [25] lengths between 700 nm [26] and 40 μm; [27] and interwire distances from 22 [28] to 430 nm. [29] In most cases, PAA templates are of high-purity aluminum, [24,27,28,[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] and although the use of low-purity Al for the fabrication of Nws is attractive due to its reasonable price (a thousand times cheaper than those of high purity), [47,48] very few reports can be found in the literature.…”