US Patent 7501688 Spin injection magnetization reversal element

A spin injection magnetization reversal element includes a ferromagnetic fixed layer, an isolation layer and a ferromagnetic free layer. The area of contact between the ferromagnetic fixed layer and the isolation layer is larger than an area of contact between the ferromagnetic free layer and the isolation layer. The ferromagnetic fixed layer may be divided into ferromagnetic first fixed layer and ferromagnetic second fixed layer, and the isolation layer may be divided into first isolation layer and second isolation layer. The ferromagnetic first fixed layer may be arranged on one of opposed principal surfaces of the ferromagnetic free layer with the first isolation layer in between, and the ferromagnetic second fixed layer may be arranged on the other of the opposed principal surfaces of the ferromagnetic free layer with the second isolation layer in between. The element holds recorded magnetization and can reverse magnetization with a small current density.