Patent ID: 7580231

Claim:
A magneto-resistive element comprising; a pinned layer whose magnetization direction is fixed with respect to an external magnetic field; a free layer whose magnetization direction is changed in accordance with the external magnetic field; and a spacer layer which is sandwiched between said pinned layer and said free layer, said spacer layer being made of copper, wherein said magneto-resistive element is configured such that sense current is applied in a direction that is perpendicular to layer surfaces, wherein said free layer comprises: a nonmagnetic layer that includes copper as a main component, and ternary alloy layers each including cobalt (Co), iron (Fe), and nickel (Ni), said ternary alloy layers being disposed on both sides of said nonmagnetic layer, wherein said ternary alloy layer includes nickel and iron at a composition ratio in which a ratio x of an atomic percentage of nickel to a total atomic percentage of nickel and iron is 27%≦x≦45%, and wherein said free layer consists of one nonmagnetic layer and two ternary alloy layers which are provided on both sides of said nonmagnetic layer, and wherein a thickness t of each ternary alloy layer is in a range of 1.3 nm≦t≦3.5 nm.