JP2773258B2 - Magnetoresistive read head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a self-bias type magnetoresistive read head used in a magnetic disk drive or a magnetic tape drive, etc., in which the demagnetizing field is increased even if the element length of the MR element is shortened. The purpose is to improve the reproduction efficiency by preventing the generation of return magnetic domains, and to shield the magnetic field through a non-magnetic insulating layer on both sides so as to sandwich the magnetoresistive effect element with a lead conductor layer joined to both ends. In a head configuration provided with a body, the magnetoresistive element has a length equal to the track width of the corresponding medium, and the lead conductor layers joined to both ends thereof are formed of a soft material having a smaller magnetoresistive effect than the magnetoresistive element. The element is made of a magnetic material and has a length portion extending both ends of the element.

[Industrial applications]

The present invention relates to a magnetoresistive read head used for a magnetic disk device or a magnetic tape device, and more particularly to a self-bias type magnetoresistive effect capable of obtaining good read magnetic characteristics for a magnetic recording medium having a high track density. It relates to a mold reproducing head.

2. Description of the Related Art Magnetic disk devices or magnetic tape devices are widely used as external storage devices of computer systems. Recently, recording densities have been increased with the increase in capacity and speed. There is a demand for a high-performance reproducing magnetic head that can be obtained. For this reason, a magnetoresistive effect reproducing head (hereinafter referred to as an MR element) using a magnetoresistive element (hereinafter abbreviated as MR element) capable of obtaining a relatively high output without depending on the medium speed as satisfying such requirements. (Abbreviated as MR head).

When the element length (element width) of the MR element is shortened corresponding to the track width by increasing the track density by increasing the track density of such an MR head, the demagnetizing field is strengthened, and the magnetic domain structure of the element becomes unstable, and the reproduction characteristics deteriorate. Tend to. For this reason,
Even if the element length of such an MR element is shortened, a demagnetizing field is not strengthened, and a head configuration with good reproduction characteristics in which a uniaxial magnetic domain structure is stably maintained in the element length direction is required.

[Conventional technology]

As shown in the perspective view of the main part of FIG. 3, a conventional self-bias type MR head is composed of an Ni-Fe Mn formed by joining nonmagnetic lead conductor layers 14a and 14b made of Cu, Al, etc. at both ends.
On both sides of the R element 13, a Ni—Zn ferrite member 11 and a shield magnetic layer 15 made of Ni—Fe are arranged via nonmagnetic insulating layers 12a and 12b made of SiO ₂ or the like.

As shown in FIG. 4, the MR element 13 is provided with magnetic anisotropy so that the direction of the element length W becomes the axis of easy magnetization, and the magnetic field generated by the current flowing through the MR element 13 causes magnetization. The leakage magnetic field from the shielded magnetic layer 15
The magnetic field is applied as a bias magnetic field, and a change in the resistance value generated in accordance with the magnetic flux from the medium in the direction of the hard axis of the MR element 13 is drawn out at both ends and read out as a voltage change from the conductor layers 14a and 14b. I have.

[Problems to be solved by the invention]

By the way, the conventional MR head having the above configuration is
When used for reproducing a medium with a high track density, the element length (element width) W of the MR element 13 corresponds to the narrow track width.
Need to be shorter.

However, as shown in FIG. 5 (a), as the element length W of the MR element 13 is shortened to Wa, the demagnetizing field in the direction opposite to the magnetization in the element length direction becomes stronger, and the magnetic domain of the MR element 13 becomes larger. The structure confines the magnetic flux and generates a return magnetic domain consisting of a plurality of magnetic domains that reduces the magnetostatic energy.

Therefore, there is a problem that the reproduction efficiency is reduced, and the domain wall of the magnetic section moves discontinuously due to the external magnetic field, thereby causing Barkhausen noise.

In view of the above-mentioned conventional problems, the present invention provides a novel magnetoresistive effect type reproducing device which does not increase the demagnetizing field even if the element length of the MR element is shortened, and prevents the generation of the return magnetic domain to improve the reproducing efficiency. It is intended to provide a head.

[Means for solving the problem]

In order to achieve the above-described object, the present invention provides a head configuration in which a shield magnetic body is provided on both sides with a non-magnetic insulating layer interposed therebetween so as to sandwich a magnetoresistive element in which a lead conductor layer is joined to both ends. The resistance effect element has a length equal to the track width of the corresponding medium, and the lead conductor layers joined to both ends thereof are made of a soft magnetic material having a smaller magnetoresistance effect than the magnetoresistance effect element, and both ends of the element are connected to each other. With a length portion that extends the

(Operation)

Since the MR head of the present invention has a configuration in which extended portions of a lead conductor layer made of a soft magnetic material having a smaller magnetoresistance effect than the MR element are joined to both ends of the MR element having a shorter element length (element width), respectively. As shown in Fig. 5 (b), MR
The demagnetizing field generated in the element length direction in the direction opposite to the magnetization of the element is reduced, and the generation of the return magnetic domain is also eliminated.

As a result, the MR element has a uniaxial magnetic domain structure that is stable in the element length direction, and the reproduction efficiency is improved. Further, generation of Barkhausen noise is also prevented.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view of a principal part showing an embodiment of a magnetoresistive read head according to the present invention, and FIG. 2 is a perspective view of a principal part showing an embodiment of the magnetoresistive element (MR element). .

In FIG, Ni-Zn, ferrite members consisting of Mn-Zn or the like for the magnetic shield 11, 15 is a magnetic layer for shielding made of Ni-Fe, a non-magnetic insulating layer 12a made of SiO ₂ or the like during this time, Lead-out conductor layers 22a and 22b formed by soft magnetic films made of amorphous Co-Zr or the like having a small magnetoresistance effect at both ends via 12b are joined, for example, Ni- having a length corresponding to the narrow track width of the medium. An MR element 21 made of Fe is provided.

As shown in more detail in FIG. 2, the structure of the MR element 21 is formed at both ends of the MR element 21 made of Ni-Fe having a short element length corresponding to the narrow track width, in the element length direction from the both ends. The MR element 21 has an extension portion 221a, 221b extending by a predetermined length, and the Ni--Fe constituting the MR element 21 is compared with the electric resistance change rate with respect to an external magnetic field by about two digits, and has a high magnetic flux density. Amorphous Co-Zr with high magnetic permeability and soft magnetic properties
Lead conductor layer 22 formed of a soft magnetic film made of
a and 22b are joined.

Therefore, the presence of the extended portions 221a and 221b of the respective lead conductor layers 22a and 22b joined to both ends of the MR element 21 detects the magnetic flux from the medium during reproduction.
No adverse effect on the reproduction signal of 21
The generation of the demagnetizing field at 21 can be significantly reduced, and the generation of the return magnetic domain is also eliminated.

In the above embodiment, an example was described in which a soft magnetic film made of amorphous Co-Zr was used for the lead conductor layer. In addition to such a soft magnetic film, for example, sendust (Al-Si-Fe) The same effect can be obtained by using a magnetic film such as Fe-Si.

〔The invention's effect〕

As is apparent from the above description, according to the magnetoresistive read head according to the present invention, even if the element length of the MR element is shortened to correspond to the narrow track width of the medium, the MR element does not react. Generation of a magnetic field is remarkably reduced, and generation of a return magnetic domain and generation of Barkhausen noise caused by the return magnetic domain can be prevented.

Accordingly, the present invention has excellent effects in practical use, such as improvement in the efficiency at the time of reproduction from a magnetic recording medium with a high track density and excellent reproduction characteristics.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main part of an embodiment of a magnetoresistive read head according to the present invention, FIG. 2 is a perspective view showing an embodiment of a magnetoresistive element of the present invention, and FIG. FIG. 4 is a perspective view showing a conventional magnetoresistive element, and FIG. 5 is a diagram for explaining problems of the conventional example and a solution according to the present invention. FIG. 1 and 2, 11 is a ferrite member, 12a and 12b are non-magnetic insulating layers, 15 is a shield magnetic layer, 21 is an MR element, 22a and 22b are lead conductor layers, and 221a and 221b are extended portions. Shown respectively.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Fumitake Suzuki 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Hitoshi Takagi 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Within Fujitsu Limited ( 56) References JP-A-61-296522 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 5/39

Claims (1)

(57) [Claims] 1. A head structure in which a shield magnetic body is provided on both sides via a non-magnetic insulating layer so as to sandwich a magnetoresistive element in which a lead conductor layer is joined to both ends, wherein the magnetoresistive elements correspond to each other. A lead conductor layer having a length equal to the track width of the medium and joined to both ends thereof is made of a soft magnetic material having a smaller magnetoresistive effect than the magnetoresistive effect element, and has a length extending both ends of the element. A magnetoresistive read head comprising: