Investigation of the lateral magnetic force and stiffness between a high-<i>T</i> <i>c</i> superconductor and magnet of rectangular shapes

Abstract

A new experimental setup has been designed to measure with high-resolution the horizontal force between a permanent magnet levitating over a high-temperature superconductor. We have studied the lateral stability as well as elastic stiffness associated with small-amplitude (&amp;lt;10 μm) vibrational motion both as functions of levitation height and relative horizontal displacements. The results, obtained for a sintered sample of YBa2Cu3Ox and a NdFeB magnet of rectangular geometry, are found to agree well with a recent quantitative theory applicable to granular superconductors.