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US 7,397,637 B2Granted
Sensor with in-stack bias structure providing enhanced magnetostatic stabilization
AssigneeHitachi Global Storage Technologies Netherlands B.V.
InventorHardayal Singh Gill
Life of this patent
Estimating the term…
Abstract
A magnetic head having an in-stack bias structure and a free layer structure. The in-stack bias structure includes an antiferromagnetic layer, and first through fourth antiparallel (AP) pinned bias layers separated by three AP coupling layers. A first spacer layer is positioned above the fourth bias layer of the bias structure. A free layer is positioned above the first spacer layer. The fourth bias layer magnetostatically stabilizes the free layer.
Claims33
A magnetic head, comprising:
- an in-stack bias structure, comprising
- an antiferromagnetic layer;
- a first bias layer positioned above the antiferromagnetic layer, a magnetic moment of the first bias layer being pinned by the antiferromagnetic layer;
- a first antiparallel coupling layer positioned adjacent the first bias layer;
- a second bias layer positioned adjacent the first antiparallel coupling layer and having a magnetic moment pinned antiparallel to the magnetic moment of the first bias layer;
- a second antiparallel coupling layer positioned adjacent the second bias layer;
- a third bias layer positioned adjacent the second antiparallel coupling layer and having a magnetic moment pinned antiparallel to the magnetic moment of the second bias layer;
- a third antiparallel coupling layer positioned adjacent the third bias layer;
- a fourth bias layer positioned adjacent the third antiparallel coupling layer and having a magnetic moment pinned antiparallel to the magnetic moment of the third bias layer;
- a first spacer layer positioned above the fourth bias layer of the bias structure;
- and
- a free layer positioned above the first spacer layer,
- wherein the fourth bias layer magnetostatically stabilizes the free layer.
10 more elements
A magnetic head, comprising:
- an in-stack bias structure, comprising
- an antiferromagnetic layer;
- a first bias layer positioned above the antiferromagnetic layer, a magnetic moment of the first bias layer being pinned by the antiferromagnetic layer;
- a first antiparallel coupling layer positioned adjacent the first bias layer;
- a second bias layer positioned adjacent the first antiparallel coupling layer and having a magnetic moment pinned antiparallel to the magnetic moment of the first bias layer;
- a second antiparallel coupling layer positioned adjacent the second bias layer;
- a third bias layer positioned adjacent the second antiparallel coupling layer and having a magnetic moment pinned antiparallel to the magnetic moment of the second bias layer;
- a third antiparallel coupling layer positioned adjacent the third bias layer;
- a fourth bias layer positioned adjacent the third antiparallel coupling layer and having a magnetic moment pinned antiparallel to the magnetic moment of the third bias layer;
- a first spacer layer positioned above the fourth bias layer of the bias structure;
- and
- a free layer positioned above the first spacer layer,
- wherein the fourth bias layer magnetostatically stabilizes the free layer,
- wherein the first bias layer is positioned at least 100 Å from the free layer.
11 more elements
A magnetic head, comprising:
- an in-stack bias structure, comprising
- an antiferromagnetic layer;
- a first bias layer positioned above the antiferromagnetic layer, a magnetic moment of the first bias layer being pinned by the antiferromagnetic layer;
- a first antiparallel coupling layer positioned adjacent the first bias layer;
- a second bias layer positioned adjacent the first antiparallel coupling layer and having a magnetic moment pinned antiparallel to the magnetic moment of the first bias layer;
- a second antiparallel coupling layer positioned adjacent the second bias layer;
- a third bias layer positioned adjacent the second antiparallel coupling layer and having a magnetic moment pinned antiparallel to the magnetic moment of the second bias layer;
- a third antiparallel coupling layer positioned adjacent the third bias layer;
- a fourth bias layer positioned adjacent the third antiparallel coupling layer and having a magnetic moment pinned antiparallel to the magnetic moment of the third bias layer;
- a first spacer layer positioned above the fourth bias layer of the bias structure;
- a free layer positioned above the first spacer layer;
- and
- an antiparallel pinned layer structure positioned towards the free layer structure on an opposite side of the free layer structure relative to the bias structure, the antiparallel pinned layer structure having at least two pinned layers having magnetic moments that are self-pinned antiparallel to each other
- wherein the fourth bias layer magnetostatically stabilizes the free layer,
- wherein a thickness of each of the first and third antiparallel coupling layers is about 10 Å to about 20 Å.
12 more elements
Dependencies are inferred from the claim text.