Patent ID: 8059374

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 with a top surface formed on the pinned layer; (c) a composite free layer contacting the top surface of the tunnel barrier layer; 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 %, and 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%, and 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 negative magnetostriction and is formed on the insertion layer; and (d) a capping layer formed on the second ferromagnetic layer in the composite free layer.