Patent ID: 7193890

Claim:
A magnetoresistive effect device comprising: a first ferromagnetic layer having a fixed magnetization direction and having magnetic moment m 1 per unit area; a nonmagnetic layer contacting with the first ferromagnetic layer, having an amplitude h 1 of roughness of an interface between the nonmagnetic layer and the first ferromagnetic layer; a second ferromagnetic layer contacting with the nonmagnetic layer on an opposite side to the first ferromagnetic layer, having a fixed magnetization direction, having magnetic moment m 2 per unit area which is smaller than the magnetic moment m 1 , and having an amplitude h 2 of roughness of an interface between the second ferromagnetic layer and the nonmagnetic layer; a barrier layer contacting with the second ferromagnetic layer on an opposite side to the nonmagnetic layer, and having an amplitude h 3 of roughness of an interface between the barrier layer and the second ferromagnetic layer, the amplitude h 3 being smaller than the amplitudes h 1 and h 2 ; and a third ferromagnetic layer contacting with the barrier layer on an opposite side to the second ferromagnetic layer and having a variable magnetization direction.