US 6,262,869 B1 · Spin valve sensor with encapsulated keeper layer and method of making

Abstract

A spin valve sensor is provided with a keeper layer which forms a partial flux-closure with a reference layer so as to minimize sensitivity of readback signal asymmetry to the sensor stripe height while maintaining a high readback signal. The keeper layer is encapsulated with top and bottom oxide layers, as well as first and second side oxide layers which form contiguous junctions with first and second side edges of the keeper layer. The top oxide layer may be a seed layer for the spin valve sensor for improving its giant magnetoresistance properties. The bottom oxide layer may be an antiferromagnetic film for pinning the magnetic moment of the keeper layer. The first and second side oxide layers function as refill first gap layers for minimizing the risk of electrical shorts between the bottom shield layer and the first and second hard bias and lead layers of the read head.

Claims47

Dependent claims

A magnetic read head that has an air bearing surface (ABS) comprising:

nonmagnetic nonconductive top and bottom read gap layers;
a spin valve sensor being located between the top and bottom read gap layers;
top and bottom shield layers;
and
the top and bottom read gap layers being located between the top and bottom shield layers;
the spin valve sensor including:
a ferromagnetic reference layer;
an antiferromagnetic first pinning layer exchange coupled to the reference layer for pinning a magnetic moment of the reference layer;
a ferromagnetic sense layer having a magnetic moment;
a nonmagnetic electrically conductive spacer layer located between the reference layer and the sense layer;
a ferromagnetic keeper layer for providing flux closure for at least a portion of a demagnetizing field of the reference layer;
a nonmagnetic nonconductive separation insulation layer located between the sense layer and the keeper layer;
and
each of the keeper layer and the separation insulation layer having first and second side edges that extend transverse to said ABS;
and
nonmagnetic nonconductive first and second side insulation layers;
and
a first side edge of the first side insulation layer abutting the first side edge of each of the keeper and the separation insulation layers and a first side edge of the second side insulation layer abutting the second side edge of each of the keeper and the separation insulation layers.

15 more elements

A magnetic head assembly including a read head and a write head and an ABS comprising:

the write head including:
ferromagnetic top and bottom pole piece layers;
each of the top and bottom pole piece layers having a yoke portion located between a pole tip portion and a back gap portion;
a nonmagnetic write gap layer located between the pole tip portions of the top and bottom pole piece layers;
an insulation stack with at least one coil layer embedded therein located between the yoke portions of the top and bottom pole piece layers;
and
the top and bottom pole piece layers being connected at their back gap portions;
and
the read head including:
a read sensor having first and second side edges;
first and second hard bias and lead layer structures connected to the first and second side edges of the read sensor;
nonmagnetic nonconductive top and bottom read gap layers;
the read sensor and the first and second hard bias and lead layers being located between the top and bottom read gap layers;
a ferromagnetic bottom shield layer;
and
the top and bottom read gap layers being located between the bottom shield layers and the first pole piece layer;
and
the read sensor including:
a ferromagnetic reference layer and an antiferromagnetic first pinning layer, the first pinning layer being exchange coupled to the reference layer for pinning a magnetic moment of the reference layer in a first direction;
a nonmagnetic electrically conductive spacer layer and a ferromagnetic sense layer, the sense layer having a magnetic moment that is free to rotate in response to signal fields;
the spacer layer being located between the reference layer and the sense layer;
a ferromagnetic keeper layer for providing flux closure for at least a portion of a demagnetizing field of the reference layer;
a nonmagnetic nonconductive separation insulation layer located between the sense layer and the keeper layer;
and
each of the keeper layer and the separation insulation layer having first and second side edges that extend transverse to said ABS;
and
nonmagnetic nonconductive first and second side insulation layers;
and
the first side edge of the first side insulation layer abutting the first side edge of each of the keeper and separation insulation layers and the first side edge of the second side insulation layer abutting the second side edge of each of the keeper and separation insulation layers.

26 more elements

A magnetic disk drive having at least one slider that has an air bearing surface (ABS), the slider supporting at least one magnetic head assembly that includes a read head and a write head, the disk drive comprising:

the write head including:
top and bottom pole piece layers;
each of the top and bottom pole piece layers having a yoke portion located between a pole tip portion and a back gap portion;
a nonmagnetic write gap layer located between the pole tip portions of the top and bottom pole piece layers;
an insulation stack with at least one coil layer embedded therein located between the yoke portions of the first and second pole piece layers;
and
the top and bottom pole piece layers being connected at their back gap portions;
and
the read head including:
a read sensor having first and second side edges;
first and second hard bias and lead layer structures abutting the first and second side edges of the read sensor;
nonmagnetic nonconductive top and bottom read gap layers;
the read sensor and the first and second hard bias and lead layers being located between the top and bottom read gap layers;
a ferromagnetic bottom shield layer;
and
the top and bottom read gap layers being located between the bottom shield layer and the bottom pole piece layer;
and
the sensor including:
a ferromagnetic reference layer and an antiferromagnetic first pinning layer, the first pinning layer being exchange coupled to the reference layer for pinning a magnetic moment of the reference layer in a first direction;
a nonmagnetic electrically conductive spacer layer and a ferromagnetic sense layer, the sense layer having a magnetic moment that is free to rotate;
and
the spacer layer being located between the reference layer and the sense layer;
a ferromagnetic keeper layer for providing flux closure for at least a portion of a demagnetizing field from the reference layer;
a nonmagnetic nonconductive separation insulation layer located between the sense layer and the keeper layer;
and
each of the keeper layer and the separation insulation layer having first and second side edges that extend transverse to said ABS;
and
the read head including:
nonmagnetic nonconductive first and second side insulation layers;
and
the first side edge of the first side insulation layer abutting the first side edge of each of the keeper and separation insulation layers and the first side edge of the second side insulation layer abutting the second side edge of each of the keeper and separation insulation layers;
a housing;
a magnetic disk rotatably supported in the housing;
a support mounted in the housing for supporting the magnetic head assembly with its ABS facing the magnetic disk so that the magnetic head assembly is in a transducing relationship with the magnetic disk;
a spindle motor for rotating the magnetic disk;
an actuator connected to the support for moving the magnetic head assembly to multiple positions with respect to said magnetic disk;
and
a processor means connected to the magnetic head assembly, to the spindle motor and to the actuator for exchanging signals with the magnetic head assembly, for controlling movement of the magnetic disk and for controlling the position of the magnetic head assembly.

35 more elements

A method of making a magnetic read head that has an air bearing surface (ABS) comprising the steps of:

forming nonmagnetic nonconductive top and bottom read gap layers;
forming a spin valve sensor between the top and bottom read gap layers;
forming top and bottom shield layers;
and
forming the top and bottom read gap layers between the top and bottom shield layers;
a making the spin valve sensor comprising the steps of:
forming a ferromagnetic reference layer and an antiferromagnetic first pinning layer with the first pinning layer being exchange coupled to the reference layer for pinning a magnetic moment of the reference layer in a first direction;
forming a nonmagnetic electrically conductive spacer layer and a ferromagnetic sense layer with the spacer layer being located between the reference layer and the sense layer and with the sense layer having a magnetic moment;
forming a ferromagnetic keeper layer for providing flux closure for at least a portion of a demagnetizing field from the reference layer;
forming a nonmagnetic nonconductive separation insulation layer between the sense layer and the keeper layer;
and
forming each of the keeper layer and the separation insulation layer with first and second side edges that extend transverse to said ABS;
and
forming nonmagnetic nonconductive first and second side insulation layers with the first side edge of the first side insulation layer abutting the first side edge of each of the keeper and separation insulation layers and the first side edge of the second side insulation layer abutting the second side edge of each of the keeper and separation insulation layers.

11 more elements

A method of making a magnetic head assembly having a read head and a write head comprising the steps of:

a forming of the write head comprising the steps of:
forming ferromagnetic top and bottom pole piece layers with a yoke portion between a pole tip portion and a back gap portion;
forming a nonmagnetic write gap layer between the pole tip portions of the top and bottom pole piece layers;
forming an insulation stack with at least one coil layer embedded therein in the yoke portions of the top and bottom pole piece layers;
and
connecting the top and bottom pole piece layers at their back gaps portions;
and
a forming of the read head comprising the steps of:
forming nonmagnetic nonconductive top and bottom read gap layers;
forming a spin valve sensor between the top and bottom read gap layers;
forming a ferromagnetic bottom shield layer;
and
forming the top and bottom read gap layers between the bottom shield layer and the bottom pole piece layer;
and
a making of the spin valve sensor comprising the steps of:
forming a ferromagnetic reference layer and an antiferromagnetic first pinning layer with the first pinning layer being exchange coupled to the reference layer for pinning a magnetic moment of the reference layer in a first direction;
forming a nonmagnetic electrically conductive spacer layer and a ferromagnetic sense layer with the spacer layer being located between the reference layer and the sense layer and with the sense layer having a magnetic moment;
forming a ferromagnetic keeper layer for providing flux closure for at least a portion of a demagnetizing field from the reference layer;
forming a nonmagnetic nonconductive separation insulation layer between the sense layer and the keeper layer;
and
forming each of the keeper layer and the separation insulation layer with first and second side edges that extend transverse to said ABS;
and
forming nonmagnetic nonconductive first and second side insulation layers with the first side edge of the first side insulation layer abutting the first side edge of each of the keeper and separation insulation layers and the first side edge of the second side insulation layer abutting the second side edge of each of the keeper and separation insulation layers.

20 more elements

A method of making a magnetic read head that has an air bearing surface (ABS) and a track width at the ABS, comprising;

forming a nonmagnetic electrically insulative first read gap layer;
forming a ferromagnetic keeper material layer, which has a keeper layer portion located between first and second side portions, on the first read gap layer;
forming a nonmagnetic electrically insulative separation insulation material layer having an separation insulation layer portion on the keeper layer portion and first and second side portions on the first and second side portions respectively of the keeper material layer;
forming a bilayer photoresist mask on the separation insulation material layer covering the separation insulation layer portion and the keeper layer portion and leaving the first and second side portions of the separation insulation material layer uncovered;
milling away the first and second side portions of each of the separation insulation material layer and the keeper material layer leaving each of the separation insulation layer portion and the keeper layer portion with first and second side edges;
depositing nonmagnetic electrically insulative first and second side insulation layers with the first side insulation layer abutting the first side edge of each of the separation insulation layer portion and the keeper layer portion and the second side insulation layer abutting the second side edge of each of the separation insulation layer portion and the keeper layer portion;
removing the bilayer photoresist mask;
depositing a ferromagnetic sense material layer, which has a sense layer portion between first and second side portions, on the separation insulation layer portion and the first and second side insulation layers;
depositing a nonmagnetic electrically conductive spacer material layer, which has a spacer layer portion between first and second portions, on the sense layer portion and the first and second side portions respectively of the sense material layer;
depositing a ferromagnetic reference material layer, which has a reference layer portion between first and second side portions, on the spacer layer and the first and second side portions of the sense material layer;
depositing an antiferromagnetic first pinning material layer, which has a first pinning layer portion between first and second side portions, on the reference layer portion and the first and second side portions respectively of the reference material layer;
forming a second bilayer mask on the antiferromagnetic first pinning layer portion leaving first and second side portions of each of the antiferromagnetic first pinning material layer, the reference layer portion, the spacer layer portion and the sense layer portion uncovered by the second bilayer mask;
milling away the first and second portions of each of the antiferromagnetic first pinning material layer, the reference material layer, the spacer material layer and the sense material layer leaving each of the first pinning layer portion, the reference layer portion, the spacer layer portion and the sense layer portion with first and second side edges;
depositing first and second hard bias and lead layers with the first hard bias and lead layers abutting the first side edge of each of the first pinning layer portion, the reference layer portion, the spacer layer portion and the sense layer portion, and the second hard bias and lead layers abutting the second side edge of each of the first pinning layer portion, the reference layer portion, the spacer layer portion and the sense layer portion;
and
removing the second bilayer photoresist mask.

13 more elements

Dependencies are inferred from the claim text.

Spin valve sensor with encapsulated keeper layer and method of making

Life of this patent

Spin valve sensor with encapsulated keeper layer and method of making

Life of this patent

Abstract

Claims47