Patent ID: 7961438

Claim:
A magnetoresistive device of a CPP (current perpendicular to plane) structure, comprising a magnetoresistive unit, and a first shield layer and a second shield layer which are located and formed such that the magnetoresistive unit is sandwiched between them from above and below, with a sense current applied in a stacking direction, characterized in that: said magnetoresistive unit comprises a nonmagnetic intermediate layer, and a first ferromagnetic layer and a second ferromagnetic layer stacked and formed such that said nonmagnetic intermediate layer is sandwiched between them, said first shield layer and said second shield layer are each controlled by magnetization direction control means in terms of magnetization direction to create an antiparallel magnetization state where their magnetizations are in opposite directions, said first ferromagnetic layer and said second ferromagnetic layer are exchange coupled to said first shield layer and said second shield layer, respectively, by way of a first exchange coupling function gap layer and a second exchange coupling function gap layer, with an exchange coupled strength of 0.2 to 2.5 erg/cm 2 , said first ferromagnetic layer and said second ferromagnetic layers receive such action that under magnetic actions of said first shield layer and said second shied layer, respectively, there is an antiparallel magnetization state created where their magnetizations are in opposite directions, and said first ferromagnetic layer and said second ferromagnetic layer each contain a CoFe alloy layer having a positive magnetostriction property with a magnetostriction λ in the range of 20×10 −6 to 40×10 −6 .