  Under conditions where the angular momentum of a ferromagnetic particle is
dominated by intrinsic spin, applied torque is predicted to cause gyroscopic
precession of the particle. If the particle is sufficiently isolated from the
environment, a measurement of spin precession can potentially yield sensitivity
to torque beyond the standard quantum limit. Levitation of a micron-scale
ferromagnetic particle above a superconductor is a possible method of near
frictionless suspension enabling observation of ferromagnetic particle
precession and ultrasensitive torque measurements. We experimentally
investigate the dynamics of a micron-scale ferromagnetic particle levitated
above a superconducting niobium surface. We find that the levitating particles
are trapped in potential minima associated with residual magnetic flux pinned
by the superconductor and, using an optical technique, characterize the
quasiperiodic motion of the particles in these traps.
