US 8,164,863 B2 · Current-perpendicular-to-plane (CPP) read sensor with multiple ferromagnetic sense layers

Abstract

The invention provides a current-perpendicular-to-plane (CPP) tunneling magnetoresistance (TMR) or giant magnetoresistance (GMR) read sensor with multiple ferromagnetic sense layers. In one embodiment of the invention, a CPP TMR read sensor comprises a first sense layer formed by a ferromagnetic polycrystalline Co—Fe film, a second sense layer formed by a ferromagnetic interstitial-type amorphous Co—Fe—B film, a third sense layer formed by a ferromagnetic substitute-type amorphous Co—Fe—X film where X is Hf, Zr or Y, and a fourth sense layer formed by a ferromagnetic Ni—Fe film. The third sense layer acts as a diffusion barrier layer to suppress Ni diffusion, thus allowing the incorporation of the Ni—Fe fourth sense layer for improving ferromagnetic properties of the multiple sense layers. The multiple sense layers induce spin-dependent scattering, thus facilitating the CPP TMR read sensor to exhibit a strong TMR effect.

Claims16

Dependent claims

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.

12 more elements

A hard disk drive including

a hard disk;
and
a read head that includes a current-perpendicular-to-plane (CPP) read sensor for reading data from the hard disk, the 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 nonmagneric antiparallel-coupling layer on the ferromagnetic keeper layer;
a ferromagnetic reference layer on the nonmagneric 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 nonmagnetic 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.

14 more elements

Dependencies are inferred from the claim text.

Current-perpendicular-to-plane (CPP) read sensor with multiple ferromagnetic sense layers

Life of this patent

Current-perpendicular-to-plane (CPP) read sensor with multiple ferromagnetic sense layers

Life of this patent

Abstract

Claims16