An MTJ in an MRAM array or TMR read head is disclosed in which a low
magnetization capping layer is a composite having a NiFeHf inner layer
formed on a NiFe or CoFeB/NiFe free layer, a Ta middle layer, and a Ru
outer layer on the Ta layer. For example, a low magnetization NiFeHf
layer is achieved by co-sputtering NiFe and Hf targets with a forward
power of 400 W and 200 W, respectively. A higher Hf content increases the
oxygen gettering power of the NiFeHf layer and the thickness is modified
to change dR/R, RA, and magnetostriction values. A so-called dead layer
between the free layer and capping layer is restored by incorporating a
NiFeHf layer on the free layer to improve lattice matching. The Fe
content in the NiFe target used to make the NiFeHf layer is preferably
the same as in the NiFe free layer.