Magnetic Properties of Electroless Deposited Ni–Cu–B Nanotube Arrays

We have prepared Ni-Cu-B nanotube arrays with lengths of 20 μm and outer diameter of 400 nm via electroless deposition in a polycarbonate membrane and investigated their associated magnetic properties. The nanotube composition was varied by controlling the CuSO₄ concentration in the deposition solution. The nanostructured deposit has a specific magnetization of <;1 JT^-1 Kg^-1 (~0.0065 μB / Ni atom). A pining type magnetic reversal mechanism was observed. The coercivity of the Ni-Cu-B nanostructures remained constant at 7.0 mT (5570 A/m), irrespective of Cu content. However, the anisotropy of the nanotubes increased as the Cu content increased. This indicates that by controlling the composition of magnetic nanostructures certain magnetic properties can be altered, while other properties remain constant.