A modified close cycle helium gas cryogenic system was used to measure the flux drag torque acting on a free spinning disk magnet by a single grain YBCO superconductor. It was found that at low spinning speed ( less than 8 Hz ) and constant levitation height, the flux drag torque decreased with temperature which behavior is roughly similar to the temperature dependence of the reciprocal of critical current density for a single grain superconductor.
Relation:
淡江理工學刊 = Tamkang Journal of Science and Engineering 11(2), pp.127-130
