On the superconducting suspension effect

A superconductor that expels magnetic flux perfectly (Meissner effect) is repelled by a magnet in any configuration. Yet, suspension of a high-temperature superconductor below a magnet has been demonstrated recently. It is accepted that flux pinning is the mechanism that is responsible for the observed attractive force. The author makes an approximation that is a gross exaggeration of flux pinning, under which the fields and forces are readily computed. The calculation shows why stable suspension can occur.<
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