JPH02122411A - Magneto-resistance effect type head - Google Patents

Abstract

PURPOSE:To suppress the generation of the Barkhausen noise at the time of reproducing by arranging a shielding body to pinch a head main body only in a part facing an MR (magneto-resistance effect) element, and pinching a pullout magnetic layer and a permanent magnet by non-magnetic layers. CONSTITUTION:Shielding bodies 21 and 22 are approximately in a size corresponding to an MR element 3, face the MR element of a head main body 2, and they are arranged by vertically pinching the MR element 3 through a gap layer 13. A non-magnetic layer 23 made of SiO2 and Al2O3 vertically pinches the part other than the MR element 3 of the head main body 2, namely, pullout magnetic layers 4 and 5 and a permanent magnet 6. That is, since the shielding bodies 21 and 22 are farther separated from the permanent magnet 6, a magnetic flux from the permanent magnet 6 flows not into the shielding bodies 21 and 22 but solely into the pullout magnetic layers 4 and 5. Consequently, the magnet from the permanent magnet 6 effectively flows into the MR element 3, and the magnetic field is sufficiently impressed to the MR element 3. Thus, the magnetic zone in the MR element 3 is stabilized, and the Barkhausen noise is not generated at the time of reproducing.

Description

[Detailed Description of the Invention] (Summary) The present invention relates to a magnetoresistive head for reproducing signals from a recording medium of a magnetic disk device and a magnetic tape device, and is intended to enable suppression of Barkhausin noise, using a magnetoresistive element. A head body has a head body in which a magnetic layer is protruded from both ends of the head, and both poles of a permanent magnet are magnetically coupled to the magnetic layer to apply a magnetic field to the magnetoresistive element through the magnetic layer. A magnetoresistive head, wherein a shield body sandwiching the head body is disposed only in a portion facing the magnetoresistive element, and the lead-out magnetic layer and the permanent magnet are sandwiched between non-magnetic layers. Configure.

(Industrial Application Field) The present invention relates to a magnetoresistive helad for reproducing signals from a recording medium of a magnetic disk device and a magnetic tape device.

In recent years, as magnetic recording devices, which are the external memory of computers, have become increasingly popular, high-performance magnetic heads have been required. Magnetoresistive heads, which can provide high output regardless of the media speed, meet this demand. Effective type (MR) heads are attracting attention.

In this MR head, Barkhausen noise due to irregular domain wall movement within the magnetoresistive element film is likely to occur, so it is necessary to suppress the occurrence of this noise.

[Conventional technology]

Figures 3 and 4 were previously filed by the applicant in Japanese Patent Application No. 63-1.
The structure of the magnetoresistive head 1 proposed in No. 53171 is shown.

This MR head 1 is intended to reduce Barkhausen noise. The head body 2 includes a ferromagnetic material a from both ends of a magnetoresistive element (hereinafter referred to as MR element) 3.
The magnetic layer 4.5 is drawn out and arranged, and both poles of the permanent magnet 6 are drawn out and magnetically coupled to the magnetic ff14.5. The leakage/decreasing magnetic flux from the permanent magnet 6 flows to the MR element 3 through the extraction magnetic layer 4.5 as indicated by 7.
A magnetic field H is applied to the MR element 3. This stabilizes the magnetic domains within the MR element 3 and reduces Barkhausen noise. 8.9 is a conductor layer for detection current.

10 and 11 are shield bodies made of ferromagnetic material, each of which covers the entire head body 2 and has a thickness of 5 iOz.

AL20s! ! ! The head main body 2 is sandwiched from above and below with the nonmagnetic layer 12 interposed therebetween.

The part of the nonmagnetic layer 12 located above and below the MR element 3 and sandwiched by the shield body 10.11 is the gap ff1.
3.

The shield body 10.11 is provided for the purpose of improving the resolution of the head.

14 is a substrate.

[Problem to be solved by the invention]

The shields io and 1i are formed to cover the entire head body 2.

For this reason, a part of the magnetic flux from the permanent magnet 6 flows into the shield body 10.degree. 11, as shown by reference numeral 15 in FIG.

The magnetic flux flowing into the MR element 3 decreases by the amount that flows into the shield bodies 1o and ii, the magnetic field applied to the MR element 3 decreases, and the M
The magnetic domain within the R element 3 becomes insufficiently stable, resulting in Barkhausen noise.

An object of the present invention is to provide a magnetoresistive head that can suppress Barkhausen noise.

[Means to solve the problem]

The present invention provides a head body in which a lead magnetic layer is drawn out from both ends of a magnetoresistive element, and both poles of a permanent magnet are magnetically coupled to the lead magnetic layer in order to apply a magnetic field to the magnetoresistive element through the lead magnetic layer. A magnetoresistive head comprising: a shield body sandwiching the head body; disposed only in a portion facing the magnetoresistive element; and a shield body sandwiching the head body; is sandwiched between nonmagnetic layers.

(Function) Since the shield body is not present in the portion facing the permanent magnet, leakage of magnetic flux from the permanent magnet to the shield body can be prevented. As a result, the magnetic flux from the permanent magnet flows exclusively to the magnetoresistive element via the extraction magnetic layer, the permanent magnet efficiently applies the magnetic field to the magnetoresistive element, and the magnetic domains within the magnetoresistive element are stabilized. This effectively prevents Barkhausen noise from occurring during playback.

(Embodiment) FIGS. 1 and 2 each show a magnetoresistive head 20 according to an embodiment of the present invention.

This MR head 20 is the same as the above-described MR head 1 except for the shield body, and parts corresponding to those shown in FIGS. 1 and 2, 3, and 4 are designated by the same reference numerals. The explanation thereof will be omitted.

Reference numerals 21 and 22 denote a shield body, which has a size approximately corresponding to the MR element 3, and is arranged in the head main body 2, facing the MR element 3, with the MR element 3 sandwiched from above and below via a gap N413. .

23 is s t 02 , non-magnetic F made of A12.03, t
ft', and the portions of the head body 2 other than the MR element 3, that is, the extraction magnetic layer 4.5 and the permanent magnet 6, are sandwiched between the head body 2 and the permanent magnet 6.

In the MR head 20 having the above configuration, the shield body 21
．． 22 is farther away than the permanent magnet 6, the magnetic flux from the permanent magnet 6 does not flow into the shield bodies 21 and 22, but flows exclusively into the extraction magnetic layer 4.5.

As a result, the magnetic flux from the permanent magnet 6 effectively flows to the MR element 3, and a sufficient magnetic field is applied to the MR element 3. As a result, the magnetic domain within the MR element 3 is stabilized, and Barkhausen noise is not generated during reproduction.

Therefore, according to the above MR head 2o, compared to the conventional MR head 1, signals from a recording medium can be reproduced with a better SN ratio.

(Effects of the Invention) As explained above, according to the present invention, the magnetic flux from the permanent magnet is efficiently applied to the magnetoresistive element without waste,
The magnetic domains within the magnetoresistive element are sufficiently stabilized, and Barkhausen noise during reproduction can be suppressed.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a magnetoresistive head according to an embodiment of the present invention, FIG. 2 is a sectional view of the head of the present invention, FIG. 3 is a perspective view of a conventional magnetoresistive head, and FIG. 4 is a perspective view of a magnetoresistive head according to an embodiment of the present invention. is a sectional view of a conventional head. In the figure, 2 is a head body, 3 is a magnetoresistive element, 4.5 is an extraction magnetic layer, 6 is a permanent magnet, 20 is a magnetoresistive head, 21°, 22 is a shield, and 23 is a nonmagnetic layer. .

Claims (1)

[Claims] A magnetic layer (4,
5) is drawn out, and both poles of the permanent magnet (6) are magnetically coupled to the drawing magnetic layer (4, 5) in order to apply a magnetic field to the magnetoresistive element (3) through the drawing magnetic layer (4, 5). This is a magnetoresistive head having a head body (2) with a cylindrical shape and a shield body (21, 2) sandwiching the head body (2).
2) is disposed only in a portion facing the magnetoresistive element (3), and the lead-out magnetic layer (4, 5) and the permanent magnet (6)
) sandwiched between nonmagnetic layers (23).