PRECESSION OF SPINNING MAGNETS LEVITATED OVER HIGH-TEMPERATURE SUPERCONDUCTORS

Both the experimental and theoretical aspects of the precession of a m agnet over both a melt-processed and sintered high-temperature superco nductor are explored. The freely levitated magnet is spun to high freq uencies to obtain a large angular momentum, and tilted using a second magnet. The levitated magnet slowly precesses about a position at leas t close to the center of mass of the magnet, and the tilt angle decays back to the original orientation. A simple torque equation is used to obtain the applied torque from the measured rate of change of the til t angle and the precession angle. We discuss how to relate the torques to the moments in the superconductor. (C) 1998 Elsevier science B.V.