MAGNETORESISTIVE ELEMENT AND MAGNETIC RANDOM-ACCESS MEMORY

摘要

This magnetoresistive element comprises: a first ferromagnetic layer (12) having variable magnetization substantially perpendicular to a film surface; a second ferromagnetic layer (16) having invariable magnetization substantially perpendicular to the film surface; a first nonmagnetic layer (14) provided between the first ferromagnetic layer and the second ferromagnetic layer; a third ferromagnetic layer (20) provided on the reverse side of the second ferromagnetic layer from the first nonmagnetic layer, the third ferromagnetic layer having magnetization substantially parallel to the film surface and generating a rotating magnetic field through the injection of spin-polarized electrons; and a second nonmagnetic layer (18) provided between the second ferromagnetic layer and the third ferromagnetic layer. The magnetization of the first ferromagnetic layer can be reversed by means of the rotating magnetic field, which is generated from the third ferromagnetic layer by passing a first electric current in either the direction from the third ferromagnetic layer through the second ferromagnetic layer towards the first ferromagnetic layer, or in the direction from the first ferromagnetic layer through the second ferromagnetic layer towards the third ferromagnetic layer. Likewise, the magnetization of the first ferromagnetic layer can be reversed to a direction different from that achieved by applying the first current by applying a second electric current having a different current density from that of the first electric current in the same direction and generating electrons that have been spin-polarized by the second ferromagnetic layer.