Magnetic properties of densely packed arrays of Ni nanowires as a function of their diameter and lattice parameter

High-quality densely packed hexagonal arrays of Ni nanowires have been prepared by filling self-ordered nanopores in alumina membranes. Nanowires with different diameter d ~18–83 nm! and lattice parameter D ~65 and 105 nm! have been studied by atomic force, high resolution scanning electron microscopies, Rutherford backscattering, and vibrating sample magnetometer techniques. Axial loops coercivity and remanence decrease with increasing ratio diameter to lattice parameter, r , until nanowires start to interconnect locally. Additionally, hysteresis of in-plane loops increases with packing factor. In order to interpret the experimental results, multipolar magnetostatic interactions among nanowires with increasing ratio r are considered. © 2004 American Institute of Physics. @DOI: 10.1063/1.1687539#