Josephson current

The Josephson effect describes the flow of electric current between two superconductors separated by a thin insulating layer. This phenomenon, predicted by Brian D. Josephson in 1962, involves the movement of electron pairs, known as Cooper pairs, across the insulator, a process called Josephson tunneling.12

Key aspects of the Josephson effect include:
* Zero-Voltage Current: A current can flow across the junction without any applied voltage, up to a certain maximum limit that is influenced by magnetic fields.2
* Oscillating Current: When a voltage is applied across the junction, the current oscillates at a very high frequency, directly proportional to the voltage.2

This effect is crucial for devices like the superconducting quantum interference device (SQUID), which are highly sensitive magnetic field detectors. Josephson junctions are also used as precise standards for voltage measurement due to their predictable behavior based on fundamental physical constants.13