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US 6,724,581 B2Granted
High moment iron nitride based magnetic head layers resistant to hard axis annealing
AssigneeInternational Business Machines Corporation
InventorJohn David Westwood
Life of this patent
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Abstract
A method employs an RF magnetron sputtering system under specific process conditions for making shield and pole piece ferromagnetic layers of a read write magnetic head wherein the magnetic anisotropy HK of the ferromagnetic layers is substantially maintained without easy axes switching when annealed along their hard axes in the presence of a magnetic field (hard axis annealing).
Claims20
A magnetic read write head having an air bearing surface (ABS) comprising:
- a spin valve sensor, nonmagnetic first and second read gap layers, a ferromagnetic first shield layer and a ferromagnetic first pole piece layer;
- the spin valve sensor being located between the first and second read gap layers and the first and second read gap layers being located between the first shield layer and the first pole piece layer;
- the spin valve sensor having a pinned layer which has a magnetic moment that is pinned by a pinning layer in a direction perpendicular to the ABS;
- a ferromagnetic second pole piece layer and a nonmagnetic write gap layer wherein the second pole piece layer is separated from the first pole piece layer by the write gap layer at the ABS and is connected to the first pole piece layer at a back gap;
- each of the first shield layer and the first and second pole piece layers having a magnetic easy axis that is directed parallel to the ABS and parallel to major thin film planes of the layers;
- an insulation stack with a coil layer embedded therein located between the first and second pole piece layers wherein the insulation stack includes at least one baked photoresist insulation layer that has been formed in part by heating at a preselected annealing temperature which is sufficient to hard bake said photoresist insulation layer in the presence of a magnetic field that is directed perpendicular to said ABS wherein said heating and magnetic field constitute hard axis annealing of the first shield layer and the first pole piece layer;
- and
- after said hard axis annealing said at least first pole piece layer having a magnetic anisotropy of at least 2.6 Oe and a hard axis to easy axis coercivity ratio of less than or equal to 0.60.
5 more elements
A magnetic disk drive including a read write magnetic head having an air bearing surface (ABS), the disk drive comprising:
- the magnetic head including:
- a spin valve sensor, first and second nonmagnetic first and second read gap layers, a ferromagnetic first shield layer and a ferromagnetic first pole piece layer;
- the spin valve sensor being located between the first and second read gap layers and the first and second read gap layers being located between the first shield layer and the first pole piece layer;
- the spin valve sensor having a pinned layer which has a magnetic moment that is pinned by a pinning layer in a direction perpendicular to the ABS;
- a ferromagnetic second pole piece layer and a write gap layer wherein the second pole piece layer is separated from the first pole piece layer by the write gap layer at the ABS and is connected to the first pole piece layer at a back gap;
- each of the first shield layer and the first and second pole piece layers having an easy axis that is directed parallel to the ABS;
- an insulation stack with a coil layer embedded therein located between the first and second pole piece layers wherein the insulation stack includes at least one baked photoresist insulation layer that has been formed in part by heating at a preselected annealing temperature which is sufficient to hard bake said photoresist insulation layer in the presence of a magnetic field that is directed perpendicular to said ABS wherein said heating and magnetic field constitute hard axis annealing of the first shield layer and the first pole piece layer;
- and
- after said hard axis annealing said at least first pole piece layer having a magnetic anisotropy of at least 2.6 Oe and a hard axis to easy axis coercivity ratio of less than or equal to 0.60;
- a housing;
- a magnetic disk rotatably supported in the housing;
- a support mounted in the housing for supporting the magnetic head with its ABS site facing the magnetic disk so that the magnetic head is in a transducing relationship with the magnetic disk;
- spindle motor for rotating the magnetic disk;
- an actuator means connected to the support for moving the magnetic head to multiple positions with respect to said magnetic disk;
- and
- a processor connected to the magnetic head, to the spindle motor and to the actuator for exchanging signals with the magnetic head, for controlling movement of the magnetic disk and for controlling the position of the magnetic head.
13 more elements
Dependencies are inferred from the claim text.