Dynamic magnetic information storage or retrieval – Head – Hall effect
Patent
1994-04-15
1997-07-01
Wolff, John H.
Dynamic magnetic information storage or retrieval
Head
Hall effect
G11B 5127
Patent
active
056444559
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to magnetoresistive heads, particularly to magnetoresistive heads for reading data from an adjacent magnetic media.
Magnetoresistive (MR) elements are widely used in magnetic transducing heads for reading data from a magnetic disk. MR elements are characterized in that the resistance of the element changes with variations in the magnetic field due to recorded data on the adjacent magnetic disk. Resistance changes in the MR element are sensed by passing a current through the element and measuring the voltage change across it, or by placing a voltage across the element and measuring the current change through it. In either case, the varying signal represents the data on the disk and the MR head provides an accurate transducer for reading high density digital information from the adjacent magnetic media. Typically, the MR element is located on the magnetic head between two thick soft magnetic films, such as Sendust or permalloy, which act as flux shields for the MR head. Typically, these shields are isolated from the MR element by electrically insulating material, such as aluminum oxide (Al.sub.2 O.sub.3).
One problem associated with MR heads is that considerable heat is often generated by current passing through the MR element. Although the current is typically small (of the order of milliamperes), the size of the MR element film is likewise small, causing a substantial concentration of the heat in the MR element. While the magnetic film shields could provide a good heat sink for dissipating excess heat generated by the MR head, the presence of the electrically insulating layer between the magnetic films and the MR element thermally insulates the MR element from the magnetic material.
There is, accordingly, a need for at least one of the half-gaps adjacent the MR element be of a material that exhibits high thermal conductivity and low electrical conductivity.
SUMMARY OF THE INVENTION
In accordance with the present invention, at least one of the half-gaps of an MR head located between the MR element and a shield is fabricated of an amorphous diamond-like carbon film having good thermal conductivity and high resistivity characteristics. Preferably, the at least one half-gap formed of the diamond-like carbon film is located between the MR element and the magnetic film formed on the supporting substrate to thereby dissipate heat. Optionally, both half-gaps may be formed of the amorphous diamond-like carbon film.
The amorphous diamond-like carbon film employed in accordance with the present invention is a very hard material resistant to abrasion. Consequently, one optional and desirable feature of the present invention resides in the inclusion of the amorphous diamond-like carbon film to the air bearing surface of the head to protect the MR element from abrasion upon take off and landing of the head against the disc.
Another optional feature of the present invention is the formation of the write gap of a write transducer with an amorphous diamond-like carbon film having good thermal conductivity and high resistivity characteristics.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a section view of one form of a head in accordance with the presently preferred embodiment of the present invention;
FIG. 2 is a frontal view of the air-beating surface of the head shown in FIG. 1; and
FIG. 3 is a partial section view, as in FIG. 1, of an MR head in accordance with a modification of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2 illustrate a magnetic head in accordance with one form of the present invention. The head includes a thick film layer 10 soft magnetic material, such as Sendust, which has been deposited on a substrate (not shown) in a customary manner. A read head 12 is formed of a first electrically insulative, non-magnetic, thermally conductive layer 14 formed of amorphous diamond-like carbon described below. MR element 16 is formed of a layer of magnetic material whose resistance varies with changes in the magneti
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Cao Allen
Seagate Technology Inc.
Wolff John H.
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