Ferromagnetic Josephson Junctions

The phenomenon of superconductivity produces ideal diamagnetism in low Tc superconductors, contradicting the ferromagnetism phenomena. Superconductivity prefers antiparallel spin orientation of the electrons in Cooper pairs, whereas ferromagnetism forces the spins to be aligned in a parallel orientation. The combination of superconductivity and ferromagnetism is attracting significant attention as a promising electronic device for large-scale integrated superconductive systems. These superconductive-ferromagnetic devices are typically composed of different number, type, and configuration of superconductive, normal metal, ferromagnetic, and insulating layers. The primary objective of these devices is to enable area and power-efficient superconductive logic. In this chapter, the physics of ferromagnetic Josephson junctions and other types of ferromagnetic JJs is reviewed.