JPS61217922A - Magneto-resistance effect type magnetic head - Google Patents

Abstract

PURPOSE:To eliminate a spike-like noise, and to improve the quality of a reproducing signal by providing a member of an electric conductor which is insulated from a magneto-resistance effect element, on at least one side of the magneto- resistance effect element, and setting this member to a DC potential. CONSTITUTION:On both sides of an MR element 12, a permeable shield film (for instance, 'Permalloy(R)') 11 having conductivity is placed through an insulating film (for instance, SiO2) 14, also a terminal 15 is drawn out of these shield films 11 having conductivity, and it is grounded. In this regard, the end part of a magnetic head consists of a structure which is exposed so as to form an opposed surface to a recording medium 13, also it forms a curved surface against the advance direction of the recording medium, and the MR element 12 is positioned at its top part. Charges by a friction, etc. can be eliminated, a spike-like noise generated at the time of running of the medium 13 in a narrow and small gap can be improved to '0' time/sec from 2-3 times/sec.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a magnetic head using a magnetoresistive element, and particularly to a structure of a magnetic head with excellent noise resistance.

[Background of the invention]

Various structures have been proposed for the magnetoresistive magnetic head (hereinafter abbreviated as MR head), for example in Japanese Patent Application Laid-Open No.
No. 10683 discloses a structure as shown in FIG.

In the figure, a magnetoresistive element (hereinafter MR hydrogen element is abbreviated) 2
, a magnetically permeable shield film 4 , and an insulating layer 4 are laminated, and the ends thereof are exposed so as to form a surface facing the recording medium 3 .

It has been found that in such a structure, there is a problem in that when the recording medium 3, which is an insulator, runs on the head surface with a narrow gap, spike-like noise is generated. After examining this problem in detail, it was found that the causes of the spike-like noise are as follows9. That is, friction or contact occurs between the medium 3 and the head surface, and as a result, the table S
Due to the generation of tortoise charges, charges are accumulated on the surface of the head,
It concentrates on the exposed portion of the head surface (directly on the shield film l) and significantly changes the potential of this conductor l.

Then, the potential difference between the M element 2 and the conductor increases, and the potential difference resembles the dielectric breakdown voltage of air.
Dielectric breakdown occurs between the The effect of this dielectric breakdown is M
A spike-like noise is observed at the output of the R element 2, and this noise lowers the signal-to-noise ratio and generates an exogenous error when information is exogenous.

[Purpose of the invention]

The present invention was made as a result of discovering the problem of spike-like noise in conventional magnetic heads, and an object of the present invention is to provide an M-type head in which such spike-like noise is reduced.

[Summary of the invention]

In order to achieve such an object, the present invention provides an electrically conductive film on both sides or one side of the MA element, which is insulated from the MA element, and connects it to a DC potential. This method is characterized by removing electric charges caused by friction etc. through an electrically conductive layer.

[Implementation sequence of the invention]

Examples of the present invention will be specifically described below.

FIG. 1 is a cross-sectional structural diagram showing an embodiment of an MR head according to the present invention. A conductive magnetically permeable shield film (permalloy in a row) is placed on both sides of the MR element 12 via an insulator (5 ioZA if it is used), and the wire 15 is pulled out from these conductive shields and grounded. Note that the end of the magnetic head is not exposed so as to form a surface facing the recording medium 13, and has a curved surface with respect to the traveling direction of the recording medium.
is located at the top. According to Honji J [[1 FIJ,
It is possible to remove electric charges due to friction, etc., and reduce the spike-like noise that occurs when the medium 13 runs through narrow gaps.
I was able to improve from times/second to θ times/second.

FIG. 2 is an IM plane structural diagram showing another S-row of the M-type head according to the present invention. In this embodiment, a conductive thin film (for example, N+Z-) is placed on an insulating and magnetic substrate (for example, N+Z-) 19
(At, Cu) 16 is provided on the other side, and M
After providing the filter element 12 and properly interposing the insulating film 14, 41!
The present invention is characterized in that a magnetic shield 11 with a magnetic conductivity is disposed, and a conductive film 16 and a conductive shield 11t are grounded. medium 13
Frictional charges generated by the running of the vehicle are removed by the thin conductor film 16 and the electrical shield 11.
It is clear that this embodiment has the same effect as the embodiment shown in FIG.

FIG. 3 is a cross-sectional structural view showing another embodiment of the M-type magnetic head according to the present invention, in which a conductive permanent magnet film, which is a bias member, is connected to one side of the M-type magnetic element 12 via an electric conductor. (Co-pt) 18 is provided, and conductive magnetically permeable shield films 11 are arranged on the outside of the M-type element 12 and the permanent magnet film 18 via an insulating film 14, respectively, and the permanent magnet 1
X18 and the two shield films 11 are grounded to remove frictional charges. It is clear that such a structure also has the same effect as the embodiment shown in FIG.

FIG. 4 is a cross-sectional structural diagram showing another embodiment of the M-type head according to the present invention, in which insulation @14 is provided on both sides of the MR element 12.
A nonmagnetic conductive film (here, At) 16 is disposed through the conductive film 16, and these are grounded. Frictional charges generated when the recording medium 13 runs on the M-type head surface through a narrow gap are immediately absorbed by the conductive film 16.

FIG. 5 shows another actual M-row of the M-head structure according to the present invention.
A conductive permanent magnet film 18, which is a bias member, is arranged on the M film element 12 via an insulating film 14, and the substrate 17 and the permanent magnet film 18 are grounded. These absorb frictional charges.

Figure 6 shows an embodiment in which the present invention is applied to a differential type M-type head, and is a view seen from the head sliding surface.
FIG. 7 is a cross-sectional view at the center of the implementation row of FIG. 6; An insulating film 1 is formed on both sides of a differential MR element 12 having a center terminal 20.
4, a conductive shield film 11 is disposed, and the shield film and the center terminal 20 of the M element 12 are connected and further grounded. According to this embodiment, by connecting the shield film 11 and the center terminal 20 of the M-type element 12 near the head, frictional charges can be removed without increasing the number of head terminals.

In the above description, the conductive bias member 18 is a permanent magnet film, but a similar effect can be obtained in an M-type head in which a conductive film through which a current is passed is used as a bias member instead.

In addition, although the conductive shield film 11 and the conductor film 16 are all grounded, by setting the potential of these films to the intermediate potential of both terminals of the M-type element 12, the insulating film and the air Discharge phenomena due to dielectric breakdown of the layer (layer between the head sliding surface of the insulating film and the recording medium) can be prevented to a minimum.

〔Effect of the invention〕

According to the present invention, it is possible to remove spike-like noise that occurs when running a medium in a narrow space.
This has the effect of extremely improving the quality of the reproduction signal of the head.

Historically, it has been possible to prevent the M-type device from being damaged or disconnected due to charging, and it also has a shielding effect against electrostatic noise from outside the M-type head.

[Brief explanation of the drawing]

Figures s1 to 5 are cross-sectional structural views showing one row of M-type heads according to the present invention, and FIG. Figure 2 is
FIG. 3 shows a row of non-shielded M heads using 4ic and magnetic substrates, and FIG.
The fourth figure shows a row of M-type heads using an insulating magnetic substrate, and FIG. Figure 6.7 shows a row of M-type heads with permanent magnet bias. Figure 8 is a cross-sectional structural diagram of a conventional shield play M-type head. l...Shield film, 2...M element, 3...Recording medium, 4...Insulating film, 6...-Air shielding film, 7
. . . Conductive magnetic substrate, 8 . . . Conductive permanent magnet film, 9 .

Claims (1)

[Claims] In a magnetoresistive magnetic head comprising a magnetoresistive element and means for applying a bias magnetic field to the element, a conductive member insulated from the magnetoresistive element is provided on at least one side of the magnetoresistive element, A magnetoresistive magnetic head characterized in that the member is set to a DC potential.