Quantum Levitation
A single crystal of sapphire wafer is coated with a thin ceramic material called yttrium barium copper oxide. The ceramic layer has no interesting magnetic or electrical properties at room temperature, but when cooled below -185ºC (-301ºF) the material becomes a superconductor. It conducts electricity without resistance, with no energy loss.
Superconductivity and magnetic field do not like each other. When possible, the superconductor will expel all the magnetic field from inside. This is the Meissner effect. In this case, since the superconductor is extremely thin, the magnetic field DOES penetrates. However, it does that in discrete quantities called flux tubes.
Inside each magnetic flux tube superconductivity is locally destroyed. The superconductor will try to keep the magnetic tubes pinned in weak areas. Any spatial movement of the superconductor will cause the flux tubes to move. In order to prevent that the superconductor remains “trapped” in midair.
(Source: quantumlevitation.com)
