Magnetic nanowires are attractive materials because of their morphology-dependent remarkable properties suitable for various advanced technologies in sensing, data storage, spintronics, biomedicine and microwave devices, etc. The recent advances in synthetic strategies and approaches for the fabrication of complex structures, such as parallel arrays and 3D networks of one-dimensional nanostructures, including nanowires, nanotubes, and multilayers, are presented. The simple template-assisted electrodeposition method enables the fabrication of different nanowire-based architectures with excellent control over geometrical features, morphology and chemical composition, leading to tunable magnetic, magneto-transport and thermoelectric properties. This review article summarizing the work carried out at UCLouvain focuses on the magnetic and spin-dependent transport properties linked to the material and geometrical characteristics.

Track etched polycarbonate membranes produced using a double energetic heavy ion irradiation with fixed incidence angles as templates to fabricate crossed magnetic nanowire networks with tunable magnetic anisotropy and microwave absorption properties.

Spin caloritronics has recently emerged from the combination of spintronics and thermoelectricity. Here, we show that flexible, macroscopic spin caloritronic devices based on large-area interconnected magnetic nanowire networks can be used to enable controlled Peltier cooling of macroscopic electronic components with an external magnetic field. We experimentally demonstrate that three-dimensional CoNi/Cu multilayered nanowire networks exhibit an extremely high, magnetically modulated thermoelectric power factor up to 7.5 mW/K²m and large spin-dependent Seebeck and Peltier coefficients of −11.5 μV/K and −3.45 mV at room temperature, respectively. Our investigation reveals the possibility of performing efficient magnetic control of heat flux for thermal management of electronic devices and constitutes a simple and cost-effective pathway for fabrication of large-scale flexible and shapeable thermoelectric coolers exploiting the spin degree of freedom.

The magnetic properties of arrays of electrodeposited Co nanowires have been studied by ferromagnetic resonance as a function of the electrolytic bath acidity and the plating current intensity. It is observed that by adjusting the pH or the plating current it is possible to find appropriate electrolyte-deposition conditions which lead to the deposition of Co nanowires with a c-axis orientation either parallel or perpendicular to the wires. At relatively high plating currents, systems containing a dominant fraction of grains having the c-axis oriented perpendicular to the wires are favoured. Such wires show a significant decrease of the effective anisotropy due to the competition between the magnetocrystalline and the shape anisotropy that can be as low as 4.3 kOe. In contrast, at low plating currents the c-axis is aligned parallel to the wires and an effective anisotropy field, that can be as high as 12 kOe, is observed.

We developed a method to fabricate ordered Co/Pt multilayer nanodot arrays using the barrier layer of anodic alumina templates as two-dimensional curved substrates. Large area patterning of self-assembled alumina nanobumps are formed with hexagonally close-packed order. The subsequent deposition of Co/Pt multilayers on this bumpy surface leads to an ordered array of single-domain nanocaps magnetized perpendicularly to the sample surface. Measurement of reversal field as a function of field angle and images of demagnetized state, composed with monobump-wide stripe domains, confirm the weakness of exchange coupling between bits.

Self-supported three-dimensionally interconnected polypyrrole nanotubes (left) with superior electrical and mechanical properties, susceptible for highly-sensitive chemiresistive detection of gaseous ammonia at concentrations as low as 1 ppm (right).