A composite material having a plurality of sections integrated into a unitary structure and each including a bulk of a superconductive metal oxide of RE--Ba--Cu--O wherein RE represents a rare earth element, the bulk of each of the sections having pinning centers and capable of trapping a magnetic field. A first one of the sections has a superconductive current density different from that of a second one of the sections. The composite material may be produced by assembling preformed respective sections into a unitary structure or by immersing one of the sections in a solution to grow crystal of Y--Ba--Cu--O superconductive on that section, followed by trimming.