Structural and magnetic properties of electrochemically assembled Ni–Pb/Al2O3 nanostructures

Ni–Pb/Al2O3 nanostructures having composition of Ni 84 at.%, Pb 16 at.% were successfully fabricated by AC electrochemically assembled within the nanopores of ordered porous alumina films prepared by a two-step anodization. SEM images revealed that the pore arrays are regularly arranged throughout the alumina film and parallel each other. TEM analyses showed that the Ni–Pb nanoarrays are polycrystalline with dimension uniformity around 20 nm in diameter and lengths up to several μm. X-Ray diffraction results revealed that the Ni–Pb nanoarrays do not form metastable alloy phase. Hysteresis loops determined by VSM indicated that the Ni–Pb/Al2O3 nanostructures obtained possess obvious magnetic anisotropy, and the perpendicular coercivity is lower than that of Ni nanowires before and after annealing.