Patent ID: 8164863

Claim:
A current-perpendicular-to-plane (CPP) read sensor comprising nonmagnetic seed layers; an antiferromagnetic pinning layer on the nonmagnetic seed layers; a ferromagnetic keeper layer on the antiferromaunetic pinning layer; a nonmagnetic antiparallel-coupling layer on the ferromagnetic keeper layer; a ferromagnetic reference layer on the nonmagnetic antiparallel-coupling layer; a nonmagnetic barrier or spacer layer on the ferromagnetic reference layer; multiple ferromagnetic sense layers formed of polycrystalline and amorphous films on the nonmagnetic barrier or spacer layer; and a cap layer on the multiple ferromagnetic sense layers; wherein the multiple ferromagnetic sense layers further comprise: a first sense layer formed by a ferromagnetic polycrystalline film; a second sense layer formed by a ferromagnetic interstitial-type amorphous film on the first sense layer; a third sense layer formed by a ferromagnetic substitute-type amorphous film on the second sense layer; and a fourth sense layer formed by another ferromagnetic polycrystalline film on the third sense layer.