Stable levitation or suspension of a heavy object in midair can be realized using a combination of a strong permanent magnet and a bulk superconductor with high critical current density, and the force density has already reached 100 kN/m². As an application, the superconducting flywheel system for energy storage is attractive, since the rotational loss of the bearing can be greatly reduced.　However, as long as a permanent magnet is used, the electromagnetic force (EMF) is essentially limited by the field strength of the permanent magnet. In order to overcome such limitations, we employed a superconducting coil/magnet as the magnetic source and studied the EMF characteristics of bulk superconductors in high magnetic fields. We also have measured the EMF between bulk superconductors and the specially designed superconducting coil with high magnetic field gradient, and confirmed the EMF reached 9000 N (force density: 1190 kN/m²).

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