Transducers for perpendicular recording with inductive cancellation at MR sensor
AssigneeWestern Digital (Fremont), LLC
InventorsDavid J. Seagle, Yugang Wang
Life of this patent
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Abstract
Perpendicular recording and magnetoresistive sensing transducers are disclosed having additional coil windings carrying current in an opposite direction to windings encircled by a core. The magnetic influence of the recording transducer on the sense transducer is reduced or eliminated. The inductance of the coils used to drive the recording transducer is reduced, facilitating high-frequency operation. Moreover, the magnetic flux induced by the coils and transmitted by the recording pole tip is increased, improving recording capabilities.
Claims20
A magnetic head for reading or writing information on relatively-moving media, the head comprising:
- a body having a media-facing surface,
- a first ferromagnetic layer disposed in said body and terminating in a first pole tip disposed adjacent to said media-facing surface,
- a second ferromagnetic layer disposed in said body and terminating in a second pole tip disposed adjacent to said media-facing surface,
- with said second pole tip having a medium-facing surface that is at least two orders of magnitude greater than that of said first pole tip, and said first and second ferromagnetic layers magnetically coupled to each other in a core region distal to said media-facing surface,
- a first electrically conductive winding section disposed within six microns of said media-facing surface and adjacent to said first ferromagnetic layer to carry a first current in a first direction, and
- a second electrically conductive winding section disposed between said first ferromagnetic layer and said second ferromagnetic layer to carry a second current in a second direction that is substantially opposite to said first direction, wherein said second electrically conductive winding section is part of an electrically conductive winding that substantially encircles said core region.
An information storage system comprising:
- a storage medium having a major surface and including a magnetic media layer having an easy axis of magnetization that is substantially perpendicular to said major surface,
- a head having a medium-facing surface disposed adjacent to said storage media,
- a first ferromagnetic core layer disposed in said head and terminating in a first pole tip disposed adjacent to said medium-facing surface,
- a second ferromagnetic core layer disposed in said head and terminating in a second pole tip disposed adjacent to said medium-facing surface,
- with said second pole tip having a medium-facing surface that is at least two orders of magnitude smaller than that of said first pole tip, and said first and second ferromagnetic core layers magnetically coupled distal to said medium-facing surface,
- a first coil spiral including a first plurality of electrically conductive winding sections disposed adjacent to said first ferromagnetic core layer to carry a current in a first direction within six microns of said medium-facing surface, and
- a second coil spiral including a second plurality of electrically conductive winding sections disposed between said first ferromagnetic core layer and said second ferromagnetic core layer to carry the current in a second direction that is substantially opposite to said first direction.
Dependencies are inferred from the claim text.