Perpendicular magnetic writer with magnetic potential control shield
AssigneeHeadway Technologies, Inc.
InventorsLijie Guan, Hung Liang Hu, Yaw Shing Tang, Kochan Ju
Life of this patent
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Abstract
Conventional perpendicular writers that utilize an extended return pole are subject to large undershoot fields. This problem has been reduced by replacing the prior art extended return pole by one whose magnetic potential has been increased relative to both the main and return poles. In a first embodiment, a second non-magnetic gap is inserted between the extended return pole and the return pole. In a second embodiment, the extended return pole is made very thin, thereby increasing its reluctance, while a third embodiment combines both reluctance-increasing features in a single design.
Claims26
A perpendicular magnetic writer comprising:
- a magnetic yoke having first and second non-parallel parts, said first part terminating as a pole tip having a lower surface;
- said pole tip lower surface being located a distance S from a recording surface;
- a conductive coil that surrounds said yoke;
- a return pole having first and second ends;
- the first end of the return pole being in magnetic contact with the magnetic yoke's second part, extending therefrom so that its second end is a surface that is coplanar with said pole tip lower surface;
- a control shield, located between said pole tip and said return pole, having a lower surface that is coplanar with said pole tip and return pole lower surfaces;
- a first non-magnetic gap between said pole tip and said control shield;
- and
- a second non-magnetic gap between said control shield and said return pole.
A perpendicular magnetic writer comprising:
- a magnetic yoke having first and second non-parallel parts, said first part terminating as a pole tip having a lower surface;
- said pole tip lower surface being parallel to and located a distance S from a recording surface;
- a conductive coil that surrounds said yoke;
- a first return pole having first and second ends;
- the first end of the first return pole being in magnetic contact with the magnetic yoke's second part, extending therefrom so that its second end is a surface that is coplanar with said pole tip lower surface;
- an extended return pole attached to the first return pole and extending therefrom towards said pole tip and having a lower surface that is coplanar with said pole tip and first return pole lower surfaces;
- a non-magnetic gap between said pole tip and said extended return pole;
- and
- said extended return pole having a thickness that is no greater than 6 times said non-magnetic gap.
A perpendicular magnetic writer comprising:
- a magnetic yoke having first and second non-parallel parts, said first part terminating as a pole tip having a lower surface;
- said pole tip lower surface being parallel to a recording surface and located a distance S therefrom;
- a conductive coil that surrounds said yoke;
- a return pole having first and second ends;
- the first end of the return pole being in magnetic contact with the magnetic yoke's second part, extending therefrom so that its second end is a surface that is coplanar with said pole tip lower surface;
- an extended return pole, having a thickness that is no greater than 6×S, located between said pole tip and said return pole and having a lower surface that is coplanar with said pole tip and return pole lower surfaces;
- a first non-magnetic gap between said pole tip and said extended return pole;
- and
- a second non-magnetic gap between said extended return pole and said return pole.
Dependencies are inferred from the claim text.