Memory cells based on superconducting and magnetic materials and methods of their control in arrays

Abstract

A memory cell having a Josephson junction and a magnetic junction in close proximity. The two junctions may be vertically integrated. The magnetic junction has at least two magnetic layers with different coercive forces and a non-magnetic layer therebetween, to form a spin valve or pseudo-spin valve. A magnetization direction of a magnetic layer with lower coercive force can be rotated with respect to the larger coercive force magnetic layer(s). Magnetic fields produced by appropriately configured control lines carrying electric current, or spin-polarized current through the magnetic junction, can result in rotation. The magnetic junction influences the Josephson critical current of the Josephson junction, leading to distinct values of critical current which can serve as digital logic states. The memory cell can be integrated into large arrays containing a plurality of the cells, to enable the selective READ and WRITE operations.