Dynamic magnetic information storage or retrieval – Head – Hall effect
Patent
1997-10-23
1999-11-16
Cao, Allen T.
Dynamic magnetic information storage or retrieval
Head
Hall effect
G11B 5127
Patent
active
059868562
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to magnetoresistive (MR) sensors. More specifically, the present invention relates to a magnetoresistive sensor having improved stability during operation.
Magnetic storage systems are used to store information in a magnetic format for subsequent retrieval. Various technologies are available for reading back the stored information. One promising technology is the use of a magnetoresistive sensor for such read back.
Magnetoresistive sensors are responsive with a change in resistivity caused by the presence of magnetic fields and are increasingly being employed as read back elements in the heads of magnetic disc drives. They are particularly advantageous because the change in resistivity is independent of disc speed and depends only on the magnetic flux. Further, the sensor output is easily scaled by adjusting the sense current.
Magnetoresistive sensors typically comprise a thin strip of ferromagnetic material such as NiFe magnetized along an easy axis of low coercivity. The strip is mounted in the head such that the easy axis is transverse to the direction of disc rotation and parallel to the plane of the disc. Magnetic flux from the disc surface causes rotation of the magnetization vector of the strip, which in turn causes a change in electrical resistivity. A sense current is passed through the thin strip and the magnetic flux can be detected by measuring the change in voltage across the element as a result of the changing resistivity.
One problem encountered with magnetoresistive sensors is Barkhausen noise which is caused by an irreversible motion of magnetic domains in the presence of an applied field, i.e., coherent rotation of the magnetization vector is non uniform and suppressed, and depends upon domain wall behavior. Barkhausen noise generated in the magnetoresistive element may be eliminated by creating a single magnetic domain in the sense current region of the magnetoresistive strip. Reduction of such Barkhausen noise generated in the magnetoresistive element is described in U.S. Pat. No. 4,803,480 entitled DOUBLE-GAP MAGNETORESISTIVE HEAD HAVING AN ELONGATED CENTRAL WRITE/SHIELD POLE COMPLETELY SHIELDING THE MAGNETORESISTIVE SENSOR STRIP IN THE READ GAP which was issued Feb. 7, 1989 to Mowry.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a transducer in a magnetic storage device includes an elongated magnetoresistive element having an active region. First and second electrical contacts are electrically coupled to the elongated magnetoresistive element on opposite sides of the active region. Information may be read from a magnetic storage medium through the electrical contacts. A bottom inductive write pole and shared shield is positioned adjacent the magnetoresistive element and has a body region and pole tip region proximate the active region. The bottom inductive write pole and shared shield includes a notch formed therein which defines the pole tip region and the body region. The notch provides a magnetic domain structure in the shared shield which offers improved stability. A top inductive write head pole is spaced apart from the bottom inductive write pole and shared shield to form a gap therebetween for magnetically writing information.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified diagram of a disc drive storage system.
FIG. 2 is a side cross-sectional view of a magnetoresistive transducer including a bottom inductive write pole and shared shield in accordance with the present invention.
FIG. 3 is a front plan view of the magnetoresistive transducer of FIG. 2.
FIG. 4 is a top plan view of a prior art shared shield.
FIG. 5 is a top plan view of a bottom inductive write pole and shared shield in accordance with the present invention.
FIG. 6 is a top plan view of a plurality of bottom inductive write poles and shared shields in accordance with another aspect of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides a magnetoresistive sensor havi
REFERENCES:
patent: 4881443 (1989-11-01), Bhattacharyya et al.
patent: 5168409 (1992-12-01), Koyama et al.
patent: 5255141 (1993-10-01), Valstyn et al.
patent: 5264980 (1993-11-01), Mowry et al.
patent: 5495378 (1996-02-01), Bonyhard et al.
patent: 5535079 (1996-07-01), Fukazawa et al.
patent: 5621595 (1997-04-01), Cohen
patent: 5633771 (1997-05-01), Yoda et al.
Johnston Alan B.
Macken Declan
Cao Allen T.
Segate Technology Inc.
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