Electrodeposition and magnetic properties of Co x Dy1−x nanotube arrays

Well-ordered Co x Dy1−x nanotubes are electrodeposited into self-made anodic aluminum oxidation templates under different potentials. The composition of Co x Dy1−x alloy nanotubes can be tuned by deposition potentials. The deposited Co x Dy1−x alloy nanotubes are amorphous, however, there appears a diffraction peak corresponding to Co7Dy2 in the sample annealed at 600 °C. The easy magnetization direction is always along the longitudinal axis of arrays for all samples. Dysprosium alloying significantly increases the coercivity of Co x Dy1−x nanotubes in comparison with Co nanotubes. By using the hybrid Monte Carlo micromagnetic method, the exchange stiffness constant of Co7Dy2 nanotubes can be conveniently estimated to be 8.0 × 10−11 J m−1.