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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 nm͒ and lattice parameter D ͑65 and 105 nm͒ 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.

An effective postgrowth electrical tuning, via an oxygen releasing method, to enhance the content of non-noble metals in deposits directly written with gas-assisted focused-electron-beam-induced deposition (FEBID) is presented. It represents a novel and reproducible method for improving the electrical transport properties of Co-C deposits. The metal content and electrical properties of Co-C-O nanodeposits obtained by electron-induced dissociation of volatile Co(CO) precursor adsorbate molecules were reproducibly tuned by applying postgrowth annealing processes at 100 °C, 200 °C, and 300 °C under high-vacuum for 10 min. Advanced thin film EDX analysis showed that during the annealing process predominantly oxygen is released from the Co-C-O deposits, yielding an atomic ratio of Co:C:O = 100:16:1 (85:14:1) with respect to the atomic composition of as-written Co:C:O = 100:21:28 (67:14:19). In-depth Raman analysis suggests that the amorphous carbon contained in the as-written deposit turns into graphite nanocrystals with size of about 22.4 nm with annealing temperature. Remarkably, these microstructural changes allow for tuning of the electrical resistivity of the deposits over 3 orders of magnitude from 26 mΩ cm down to 26 μΩ cm, achieving a residual resistivity of ρ/ρ = 0.56, close to the value of 0.53 for pure Co films with similar dimensions, making it especially interesting and advantageous over the numerous works already published for applications such as advanced scanning-probe systems, magnetic memory, storage, and ferroelectric tunnel junction memristors, as the graphitic matrix protects the cobalt from being oxidized under an ambient atmosphere.

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