Step by step reversion study in ordered array of nickel nanotubes

The reversion of magnetic moments for a hexagonal array of nickel nanotubes was analyzed. Geometric parameters were set at 1 µm for length, outer radius R = 40 nm and inner radius a = 20 nm. The angular dependence for hysteresis cycles of the array was correlated with the reported results for an individual nanotube, showing significant differences. It was indicative that inter-tubes dipolar interactions are predominant and modify the reversion behavior of the magnetic moments. The subsequent analyses of step by step reversion was carried out applying reversed magnetic fields set in 5, 10, 20 and 110 mT. The results present a smooth and periodic dynamic at low reverted field values. Close to the switching field, the reversion occurs across a complex and non-periodic process, which is characteristic of a disordered process, confirmed by the moments maps.