Patent ID: 7894244

Claim:
A tunnel magnetic resistance device comprising: an insulating film; a ferromagnetic free layer; and a ferromagnetic pinned layer formed so as to sandwich the insulating film with the ferromagnetic free layer, wherein the insulating film is a MgO film with a (100) orientation rock-salt structure, the ferromagnetic free layer includes a first ferromagnetic film and a second ferromagnetic film formed with a non-magnetic conductive layer interposed in between, the first ferromagnetic film is adjacent to the insulating film, the second ferromagnetic film and the first ferromagnetic film are anti-ferromagnetically coupled with each other, and the ferromagnetic film pinned layer includes a film having a body center cubic structure and containing Co, Fe and B, wherein the first ferromagnetic film and the second ferromagnetic film are films each having a body center cubic structure and containing Co, Fe and B, and the thickness t 1 of the first ferromagnetic film is larger than the thickness t 2 of the second ferromagnetic film.