Dynamic magnetic information storage or retrieval – Head – Magnetoresistive reproducing head
Patent
1997-10-22
2000-08-29
Korzuch, William R.
Dynamic magnetic information storage or retrieval
Head
Magnetoresistive reproducing head
G11B 539
Patent
active
061117307
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates generally to magnetoresistive (MR) heads for use in disc drive data storage systems. More particularly, the present invention relates to an MR head having separate permanent magnet (PM) layers for stabilization of the MR sensor layer and the soft adjacent layer (SAL).
In order to provide the required head performance in magnetic recording applications, it is desirable to stabilize the MR element (MRE) or sensor layer into a single magnetic domain. Stabilization of the MRE layer into a single domain is typically achieved by the use of combinations of sensor geometry, anti-ferromagnetic layers, PM magnetostatic coupling layers, or PM ferromagnetic coupling layers. In designs using a SAL for vertical bias, both the SAL and the MR layer of the MR head should be stabilized into single domain states for optimal head performance.
In PM overlaid designs, the SAL and MRE layer are both ferromagnetically coupled to the PM layer. However, in these PM overlaid designs, the head resistance is large since no low resistivity layers can be used without affecting head stability. This is due to the fact that both the MR sensor layer and the SAL must be in contact with the PM for stabilization. Consequently, a low resistance MR head utilizing SAL and overlaid PM stabilization would be a significant improvement in the art.
SUMMARY OF THE INVENTION
A magnetoresistive (MR) head for use in a data storage system is disclosed. The MR head includes an MR sensor layer and a soft adjacent layer (SAL) disposed along a length of the MR sensor layer and adapted to vertically bias the MR sensor layer. A spacer layer is formed between the MR sensor layer and the SAL in a central region of the MR head. The MR sensor layer and the SAL are independently stabilized by first and second permanent magnet (PM) layers. The PM layers are in contact with SAL and MR layers in the wing regions of the MR head. This allows a layer of low resistivity material to be placed between the first and second PM layers in the first and second wing regions in order to lower the resistance of the MR head.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic illustration, as seen from an air hearing surface (ABS) perspective, of an MR head in accordance with preferred embodiments of the present invention.
FIG. 2 is a diagrammatic illustration showing first steps in a method of fabricating the MR head shown in FIG. 1.
FIG. 3 is a diagrammatic illustration showing second steps in a method of fabricating the MR head shown in FIG. 1.
FIG. 4 is a diagrammatic illustration showing third steps in a method of fabricating the MR head shown in FIG. 1.
FIG. 5 is a diagrammatic illustration showing fourth steps in a method of fabricating the MR head shown in FIG. 1.
FIG. 6 is a diagrammatic illustration showing fifth steps in a method of fabricating the MR head shown in FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is based in part upon the recognition that, if PM stabilization of the SAL is achieved independently of the PM stabilization of the MR sensor layer in a SAL biased MR head, a low resistivity layer can be included to lower the resistance of the head. To this end, in the MR heads of the present invention, two separate PM layers are used to independently stabilize the SAL and MR sensor layers. The SAL and one of the two PM layers are ferromagnetically coupled, while the MR sensor layer and the other PM layer are ferromagnetically coupled. An additional lower resistivity layer can be sandwiched between the two PM layers, thus providing stability and low resistance at the same time.
As illustrated in FIG. 1, MR head 100 of the present invention includes first reader gap 110, SAL 120, spacer layer 130, first PM layer 140 (designated 140A and 140B in the wing regions of MR head 100), low resistivity layer 150 (designated 150A and 150B in the wing regions), second PM layer 160 (designated 160A and 160B in the wing regions), MR sensor layer or MRE 170, cap layer 180 and
REFERENCES:
patent: 5434826 (1995-07-01), Ravipati et al.
patent: 5491600 (1996-02-01), Chen et al.
patent: 5495378 (1996-02-01), Bonyhard et al.
patent: 5646805 (1997-07-01), Shen et al.
Korzuch William R.
SeagateTechnology, Inc.
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