Heinz London

Heinz London and Fritz London formulated the London equations in 1935 to describe the magnetic response of a superconductor. Zero electrical resistance alone does not specify expulsion of an existing magnetic field; their additional magnetic relation accounts for the Meissner effect. In a simple planar geometry it gives a field decaying into the material as $B(z)=B(0)e^{-z/{\lambda }_L}$, where ${\lambda }_L$ is the London penetration depth. Their phenomenological theory links a measurable penetration length to superconducting electrodynamics without supplying a microscopic pairing mechanism.^[ref]