Patent ID: 8385027

Claim:
A magnetoresistive element in a magnetic device, comprising: (a) a stack of layers comprised of a seed layer, anti-ferromagnetic (AFM) layer, and a pinned layer sequentially formed on a substrate; (b) a tunnel barrier layer or a non-magnetic spacer formed on the pinned layer; (c) a composite free layer contacting a top surface of the tunnel barrier layer or non-magnetic spacer; said composite free layer is comprised of: (1) a first ferromagnetic layer comprised of one or more of Co W Fe (100-W) , [Co W Fe (100-W) ] (100-y) B Y where w is from 0 to about 100% and y is from 10 atomic % to about 40 atomic %, or an alloy of one of the aforementioned compositions comprised of one or more additional elements including Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, and Nb, said first ferromagnetic layer has a positive magnetostriction and contacts the top surface of the tunnel barrier layer; (2) an insertion layer formed on the first ferromagnetic layer and including at least one magnetic element selected from Fe, Co, and Ni and at least one non-magnetic element selected from Ta, Ti, W, Zr, Hf, Nb, Mo, V, Mg, or Cr; and (3) a second ferromagnetic layer comprised of one or more of Co W Fe (100-W) where w is from 0 to about 100 atomic %, Ni Z Fe (100-Z) where z is from about 70% to 100%, or an alloy wherein CoFe or NiFe are combined with one or more elements selected from Ni, Ta, Mn, Ti, W, Zr, Hf, Tb, Nb, and B, said second ferromagnetic layer has a positive magnetostriction and is formed on the insertion layer; and (d) a capping layer formed on the second ferromagnetic layer in the composite free layer.