A GMR spin value structure with improved performance and a method for
making the same is disclosed. A key feature is the incorporation of a
thin ferromagnetic insertion layer such as a 5 Angstrom thick CoFe layer
between a NiCr seed layer and an IrMn AFM layer. Lowering the Ar flow
rate to 10 sccm for the NiCr sputter deposition and raising the Ar flow
rate to 100 sccm for the IrMn deposition enables the seed layer to be
thinned to 25 Angstroms and the AFM layer to about 40 Angstroms. As a
result, H.sub.EX between the AFM and pinned layers increases by up to 200
Oe while the Tb is maintained at or above 250.degree. C. When the
seed/CoFe/AFM configuration is used in a read head sensor, a higher GMR
ratio is observed in addition to smaller free layer coercivity
(H.sub.CF), interlayer coupling (H.sub.E), and H.sub.K values.