Feasibility Study of a MgB2 Superconducting Magnetic Cloak

The magnetic shielding capability of bulk MgB
₂
hollow cylinders can be fruitfully combined with an external paramagnetic sheath, to tailor the shape of the external magnetic flux lines. By appropriate selection of the external sheath permeability and thickness, it is possible to leave the magnetic flux lines unaltered by the shield (cloaking effect). Preliminary measurements have been performed at 4.2 K on shielding capability of bulk cylinders, which are subjected to axial and transversal magnetic fields up to 5 T. The cloaking conditions have been modeled to find the optimized thickness to realize the cloaking effect. The MgB
₂
material of the superconducting shield is also optimized to avoid low-temperature flux jumps, without losing its shielding capability.