Josephson, Brian David (1940– )

Welsh physicist, a leading authority on superconductivity. He shared the Nobel Prize for Physics in 1973 for his theoretical predictions of the properties of a supercurrent through a tunnel barrier (the Josephson effect), which led to the development of the Josephson junction.

Josephson was born in Cardiff and studied at Cambridge University, where he has spent most of his career, becoming professor in 1974. In 1962, Josephson saw some novel connections between solid-state theory and his own experimental problems in superconductivity. He then calculated the current due to quantum mechanical tunnelling across a thin strip of insulator between two superconductors, and the current–voltage characteristics of such junctions are now known as the Josephson effect. The Josephson effect may be used as a generator of radiation, particularly in the microwave and far infrared region, and in detecting tiny anomalies in a magnetic field.