A magnet, such as a closed, superconductive, magnetic-resonance-imaging (MRI) magnet, includes a main coil and includes a shielding coil positioned radially outward from the main coil. A magnetizable member is positioned radially outward from the main coil and radially inward from the shielding coil to supplement the strength, and increase the homogeneity of, the magnetic field created, at least in part, by the main coil and to supplement the shielding provided, at least in part, by the shielding coil.