A cryogenic memory that consists of an array of Josephson cells, i.e. memory cells containing Josephson junctions, held at a temperature very close to critical temperature. In the absence of an external magnetic field the cell is superconducting but the presence of a magnetic field destroys the superconductivity and hence the voltage across the device changes. Information is stored in the form of local variations of a magnetic field; the data is sensed by the voltage across the appropriate cell.

Josephson memories are inherently extremely fast in operation but because of the cryogenic requirements are extremely expensive to operate. The development of materials that exhibit superconductivity at higher temperatures is reducing the difficulties of using this type of memory.