Patent ID: 7760475

Claim:
A magnetoresistance effect element comprising: a pinned layer having a fixed magnetization direction; a free layer having a magnetization direction variable depending on an external magnetic field; and a nonmagnetic spacer layer disposed between said pinned layer and said free layer, said free layer including a magnetic layer comprising a CoFe film, a magnetostriction reduction layer comprising an Hf film which is a film of a 4 th group element, and Heusler alloy layer comprising a CoMnGe film, said magnetic layer, said magnetostriction reduction layer, and said Heusler alloy layer are stacked on said nonmagnetic spacer layer in this order, so that said Hf film of said magnetostriction reduction layer reduces magnetostriction of an interface between said CoFe film of said magnetic layer and said CoMnGe film of said Heusler alloy layer, and said CoMnGe film of said Heusler alloy layer, and said CoMnGe film of said Heusler alloy layer exhibits a high spin polarizability after low-temperature anneal.