Confinement of magnetic vortex and domain walls in dipolar coupled concentric nanocylinders

Ferromagnetic nanostructures have recently attracted extensive research interest, for fundamental studies of magnetism in confined geometries, and a variety of emerging applications, such as spin logic devices, magnetic sensors and magnetic nano-oscillators. Vortices and domain walls are issues of current interest in these systems . Key applications benefit from the possibility of tailoring the vortex core and the domain wall magnetic patterns. We report a theoretical study of the magnetic phases of core-shell nanocylinders, consisting of a thin Fe (Py) cylindrical core, surrounded by a few nanometers thick coaxial Py (Fe) cylindrical shell, separated by a thin nonmagnetic cylindrical layer . The Fe uniaxial anisotropy is along the X-axis direction in the core-shell surface.