Spin imbalance enhanced magnetoresistance in Co-Al-Co double-tunnel junctions

Spin-valve effect is a method that utilizes two ferromagnetic electrodes composed of parallel and antiparallel magnetization alignments to control transports of spin-polarized current. The enhancement of magnetoresistance by spin imbalance in Co-Al-Co double tunnel junctions with a superconductor as the central island. Since the central island is superconducting, the resultant nonequlibrium spin density strongly suppresses superconductivity which strongly affects the magnetoresistance. Electron-beam lithography and three-angle shadow evaporation techniques were used to prepare the samples.