London moment
The 'London moment' is a quantum-mechanical phenomenon whereby a spinning superconductor generates a magnetic field whose axis lines up exactly with the spin axis. The term may also refer to the magnetic moment of any rotation of any superconductor, caused by the electrons lagging behind the rotation of the object.
Etymology
Named for the physical scientist Fritz London, and moment as in magnetic moment.
See also
Look up london moment in Wiktionary, the free dictionary.