The trapping of magnetic field does not happen (the absence of magnetic field inside the superconductor is the Meissner effect). ... Superconductor expels magnetic field from the interior by setting up electric current at the surface.

Do superconductors produce magnetic fields?

Superconducting magnets can produce greater magnetic fields than all but the strongest non-superconducting electromagnets and can be cheaper to operate because no energy is dissipated as heat in the windings.

Do superconductors block magnetic fields?

Superconductors repel magnetic fields due to the Meissner effect. Near the surface of the superconductor material, small currents flow (without any resistance) that make an opposite magnetic field that repels the field from the magnet. We found that it doesn't behave like a pair of magnets repelling one another.