Influence of voltage variation on structure and magnetic properties of Co_1−xSn_x (X = 0.3–0.7) nanowire alloys in alumina by electrochemical deposition

The Co_1−XSn_X (X = 0.3–0.7) alloy nanowires with high density and uniform size were prepared by alternating current (AC) electrodeposition into anodized aluminum oxide templates using different AC potential from 9 to 17 V. The diameter and length of CoSn nanowires is found to be 170 nm and 1 µm, respectively, using SEM images. The formation of CoSn nanowires has been confirmed by using EDX analysis. The XRD data of all samples demonstrate the hexagonal structure of CoSn nanowires and other phase is also observed. The grain size of nanowires increases with the increase in potentials observed from the slight shift in diffraction angle toward higher values. The hysteresis curves of CoSn nanowires measured using vibrating sample magnetometer show isotropic and ferromagnetic behavior due to presence of diffuse magnetic moments and cobalt contents, respectively. When AC potential increases gradually in equal intervals, the deposition of magnetic ions decreases than that of non-magnetic ions as a result coercivity (H_C) and saturation magnetization (M_S) decreases. The substitution of more magnetic ions into CoSn alloy nanowires is found due to the increase in potential after the critical voltage (11–13 V) causing disintegration of magnetic domains, formation of defect clusters and nanostructure islands enhancing the density sites of domain walls. The increase in coercivity (Hc) and saturation magnetization (Ms) is attributed to the formation of pinning sites that obstruct the motion of domain walls due to the increase in number density of magnetic grain boundaries and phase boundaries.