JPH103618A - Yoke type magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic disk device having surface recording density of 5Gb/in<2> or above. SOLUTION: This head is constituted so that yoke films 2, 5 are shared for electrodes, and is provided with no big magneto-resistive effect film on a slide surface side, and is arranged on a position far from the slide surface by 0.5μm or above through the yoke films 2, 5. At this time, the element height of the big magneto-resistive effect film 1 is made 5μm or below, and the film thickness of the free layer of the big magneto-resistive effect film 1 is made 10nm or below, and spacing between the upper/lower yoke films 5, 2 is made 1μm or above and 10μm or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a yoke type magnetic head using a so-called giant magnetoresistive effect film, wherein the yoke film also serves as an electrode, and has a high output used for a reproducing head for recording density of 5 Gb / in ² or more. And a magnetic head having:

[0002]

2. Description of the Related Art An invention relating to a magnetoresistive magnetic head in which a current flows in a direction perpendicular to a sliding surface (JP-A-6-25133)
No. 6) has been reported. In JP-A-6-251336, the MR film is exposed on the sliding surface side and also serves as a yoke. Although the current flows perpendicular to the sliding surface as in the present invention, the present invention does not use a film having the same structure as the output source on the sliding surface, and a giant magnetoresistive film is used as the output source. As the yoke film, an NiFe-based multilayer film that does not exhibit a giant magnetoresistance effect is used. Further, although a bias conductor is provided in JP-A-6-251336, the bias conductor is not used in the present invention. In these conventional inventions, the gap of the yoke film in contact with both ends of the magnetic sensing portion, that is, the element height of the giant magnetoresistive film sandwiched between the yoke films, the thickness of the yoke film, and the thickness of the free layer of the giant magnetoresistive effect film There is no restriction on the distance between the upper and lower yoke films and the optimum length of the gap on the sliding surface side.

[0003]

SUMMARY OF THE INVENTION The present invention has a recording density of 5G.
In order to provide a magnetic head having a high output used for a read head for b / in ² or more, the thickness of the free layer of the giant magnetoresistive film serving as the magnetic sensing portion and the element height of the giant magnetoresistive film , The thickness of the yoke film, the gap between the upper and lower yoke films on the sliding surface side, the spacing between the upper and lower yoke films, the thickness of the high resistivity and high permeability material at the back contact, and the position of the giant magnetoresistive film. It is specified.

[0004]

The present invention provides a recording density of 5 Gb.
In order to provide a magnetic head having a high output used for a read head for / in ² or more, the shape of a yoke type magnetic head is specified. FIG. 1 shows the configuration near the magnetic sensing portion of the yoke type magnetic head studied in the present invention as viewed from a plane perpendicular to the sliding surface. Giant magnetoresistive film 1 serving as a magnetic sensing part, lower yoke film 2 electrically contacting giant magnetoresistive effect film 1
Supplies a current to the giant magnetoresistive film 1, and the current flows from the electrode film 3 to the upper yoke film 5 through the giant magnetoresistive film 1 and the gap film 4 on the sliding surface side. A ferromagnetic gap film 6 is used between the upper and lower yoke films of the back contact opposite to the sliding surface. On the giant magnetoresistive film between the upper and lower yoke films is an insulating film 7. In order to use the reproducing head having such a configuration at a surface recording density of 5 Gb / in ² , it is necessary to regulate the thickness and arrangement of the films constituting the head.

At a surface recording density of 5 Gb / in ² , the track width is 2 μm or less, and the gap between the upper and lower yoke films is 0.2 μm.
It is as follows. As a result of examining the necessary conditions for increasing the sensitivity under these conditions, it was found that the following conditions had to be satisfied. That is, the yoke film also serves as an electrode, and there is no giant magnetoresistive effect film on the sliding surface side. The yoke film is disposed at a distance of 0.5 μm or more from the sliding surface via the yoke film. The height is 5 μm or less, the thickness of the free layer of the giant magnetoresistive film is 10 nm or more,
The spacing between the upper and lower yoke films at the ends of the giant magnetoresistive film is 1 μm or more and 10 μm or less, and the magnetic film of the back contact is made of an insulating ferromagnetic film having a specific resistance of 1000 μΩcm or more, and the thickness of the yoke film is 0.1 μm or more. It is necessary to be.

At a surface recording density of 5 Gb / in ² , the track width is 2 μm or less, and the gap between the upper and lower yoke films is 0.2 μm.
It is as follows. As a result of studying the necessary conditions for increasing the sensitivity under these conditions, the limitation on the shape as described above was derived. The reason is described below. First, in the limitation of the position of the giant magnetoresistive film and the height of the element, the sensitivity decreases if the giant magnetoresistive film moves away from the sliding surface, but the upper and lower yoke films on the sliding surface side are interposed through the non-magnetic conductive film. The non-magnetic conductive film is in electrical contact, and the thickness of the non-magnetic conductive film determines the gap. The upper and lower yoke films need to be arranged on the back contact side from the non-magnetic conductive film in electrical contact.
At this time, the longer the spacing of the upper and lower yoke films at the end of the giant magnetoresistive film, the smaller the magnetic flux leaking from the lower yoke film to the upper yoke film side. The end of the effect film is arranged. Also,
If the position of the giant magnetoresistive film is too far from the sliding surface, the output will decrease. Therefore, it is desirable that the distance is 0.5 μm or more from the sliding surface and less than or equal to the spacing of the upper and lower yoke films. The magnetic field applied to the giant magnetoresistive film is applied through the yoke films which are in electrical contact at both ends of the giant magnetoresistive film. Considering the magnetic circuit of the upper and lower yoke films and the giant magnetoresistive film, the portion having the highest resistance is the portion where the giant magnetoresistive film is located. That is, when the element height of the giant magnetoresistive film is increased, the magnetic flux in this portion decreases, and the output decreases. Also, when the thickness of the free layer in the giant magnetoresistive film is increased, the output of the giant magnetoresistive film in the lower yoke film is similarly reduced because the sensitivity of the giant magnetoresistive film is reduced. Therefore, the free layer of the giant magnetoresistive film needs to have a thickness of 5 nm or more, and the element height of the giant magnetoresistive film needs to be 5 μm or less.
Also, since magnetic flux leaks between the upper and lower yoke films, the spacing of the upper and lower yoke films at the ends of the giant magnetoresistive film is set to 1 μm or more, so that the write head can be easily manufactured.
The following is assumed. The current flows through the giant magnetoresistive film by using an insulating ferromagnetic film having a specific resistance of 1000 μΩcm or more as the magnetic film of the back contact. The yoke film has a thickness of 0.1 μm or more.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has a recording density of 5 Gb / in ^2.
In order to provide a magnetic head having a high output used for the reproducing head for the above, the shape of the yoke type magnetic head is specified. FIG. 1 shows the yoke type magnetic head studied in the present invention as a sliding surface. The configuration near the magnetic sensing part viewed from a vertical plane is shown. The giant magnetoresistive film 1 serving as a magnetic sensing portion is composed of an antiferromagnetic film, a ferromagnetic film, a nonmagnetic conductive film, and a ferromagnetic film.
The former ferromagnetic film is in contact with the antiferromagnetic film, and the magnetization of the ferromagnetic film is fixed in one direction by exchange coupling at the interface with the antiferromagnetic film. This ferromagnetic film is called a fixed layer. Further, the magnetization of a ferromagnetic film having no interface with the antiferromagnetic film is rotated by an external magnetic field (medium magnetic field). This ferromagnetic film is called a free layer. The antiferromagnetic film is made of CrMn, CoMn, Fe
It is a Mn-based or NiMn-based alloy film or a ternary alloy obtained by adding a noble metal element to these alloys. Nonmagnetic conductive film is C
It is a film made of u, Au, Ag, or the like. The ferromagnetic films of the fixed layer and the free layer are made of NiFe alloy, CoNiFe alloy, Co, Fe, or the like. Alternatively, the giant magnetoresistive film 1 is composed of two layers of an antiferromagnetic film and a ferromagnetic film without a conductive film, and generates a magnetoresistance depending on the magnetization of the antiferromagnetic film and the direction of the magnetization of the ferromagnetic film. It is also possible. In order to allow a current to flow through the giant magnetoresistive film 1, there is a lower yoke film 2 that is in electrical contact with the giant magnetoresistive film 1, and a magnetic field from the medium is applied to the giant magnetoresistive film 1 using the yoke film as a magnetic path. Reach. The material of the yoke film is NiFe alloy,
There are a CoNiFe alloy, a multilayer film of NiFe or CoNiFe and a nonmagnetic conductive film, and a multilayer film of NiFe or CoNiFe and an insulating film. A current is supplied to the giant magnetoresistive film 1, and the current flows from the electrode film 3 to the upper yoke film 5 through the giant magnetoresistive film 1 and the gap film 4 on the sliding surface side.
A ferromagnetic gap film 6 is used between the upper and lower yoke films of the back contact opposite to the sliding surface. Since the gap film 4 is a conductive film and is on the sliding surface side, a composite material with a wear-resistant precipitation hardening alloy or oxide is used. The same material as the lower yoke film 2 is used for the upper yoke film 5. In order to control the magnetic domain of the yoke film, there is a method of bringing an antiferromagnetic film into contact with the yoke film or applying a current bias. An insulating film 7 is provided on the giant magnetoresistive film between the upper and lower yoke films, and the giant magnetoresistive film 1 is protected by an insulating protective film such as a resist or an oxide.

Next, a process of manufacturing the magnetic head will be described. The substrate is made of a material such as Al ₂ O ₃ , SiO ₂ , Si (polycrystal and single crystal), and a composite oxide. The surface of these substrates has irregularities of 5 nm or less. If the irregularities increase, the properties of the giant magnetoresistive film may deteriorate. Therefore, the surface irregularities are reduced to 5 nm or less by polishing, reverse sputtering, ion beam sputtering, and etching, and the period of the irregularities is reduced to 5 nm or less. The characteristics of the film 1 were not deteriorated. A giant magnetoresistive film is formed on a substrate having such a surface, and a 10 nm
A film containing at least one element of Ta, W, Ti, and Zr having the following film thickness is used. A giant magnetoresistive film 1 is formed on the underlayer by sputtering, vacuum evaporation, or ion beam sputtering. In this embodiment, the free layer in the giant magnetoresistive film was formed by changing the thickness from 3 nm to 20 nm. The spacing of the upper and lower yoke films, that is, the thickness of the insulating film 7 at the flat portion is set to 3
Assuming that the height of the giant magnetoresistive film 1 (the gap length near the giant magnetoresistive film 1 in the lower yoke film) is 1 μm, the relative output (Outp
ut) is 0.95 as shown in FIG. 5Gb / in ²
The required sensitivity to achieve is an output of about 0.7. Therefore, the thickness of the free layer needs to be 10 nm or less. The thickness of the fixed layer is 1 nm to 10 nm, the thickness of the nonmagnetic conductive film is 1 to 3 nm, and the thickness of the antiferromagnetic film is 10 to 30 n.
m. After the formation of the giant magnetoresistive film 1, it is processed by milling, and a yoke film 2 is formed thereon by vapor deposition or sputtering. The thickness of the yoke film is 0.1 to 1 μm. The yoke film 2 can be manufactured by a lift-off method. Next, an electrode film 3 is formed by forming a conductive film of Cu or the like. A gap film is formed on the sliding surface side. The gap film 4 can also be formed by a sputtering method or a vacuum evaporation method. The thickness of the gap film is 0.2 μm or less. FIG. 2 shows the dependence of the output on the height (element height) of the giant magnetoresistive film 1. The head output becomes 0.7 or more if the element height is 5 μm or less, and an output of 5 Gb / in ² can be achieved. Next, an insulating film 7 is formed using a resist. When the film thickness of the insulating film 7 is changed, the output also increases as the film thickness (spacing) of the insulating film increases, as shown in FIG. Considering the alignment with the write head, the spacing is small (10
μm or less). Also, the output is increased as shown in FIG. 4 where the spacing is increased. Therefore, the spacing is 1 to 10 μm. For the back contact portion between the lower yoke film 2 and the upper yoke film 5, an insulating film or a ferromagnetic insulating film 7 having a specific resistance of 1000 μΩcm or more is used between them.

From the above results, at a surface recording density of 5 Gb / in ² , the track width is 2 μm or less and the gap between the upper and lower yoke films is 0.2 μm or less. As a result of examining the necessary conditions for increasing the sensitivity under these conditions, it was found that the following conditions had to be satisfied. That is, the yoke film also serves as an electrode, and there is no giant magnetoresistive effect film on the sliding surface side. The yoke film is disposed at a distance of 0.5 μm or more from the sliding surface via the yoke film. Height 5μ
m and the thickness of the free layer of the giant magnetoresistance effect film is 1
0 nm or more, the spacing of the upper and lower yoke films at the ends of the giant magnetoresistive film is 1 μm or more and 10 μm or less, and the magnetic film of the back contact is made of an insulating ferromagnetic film having a specific resistance of 1000 μΩcm or more. Is 0.1 μm
It is necessary to be above.

[0010]

According to the present invention, the yoke film also serves as an electrode, there is no giant magnetoresistive film on the sliding surface side, and the yoke film is disposed at a distance of 0.5 μm or more from the sliding surface via the yoke film. A yoke type magnetic head in which the element height of the magnetoresistive film is 5 μm or less, the thickness of the free layer of the giant magnetoresistive film is 10 nm or less, and the spacing of the upper and lower yoke films is 1 μm or more and 10 μm or less is 5 Gb. It can be used for a magnetic disk drive having a surface recording density of / in ² or more.

[Brief description of the drawings]

FIG. 1 is a sectional view of a head having a yoke structure.

FIG. 2 is a characteristic diagram of an element height dependency of an output.

FIG. 3 is a characteristic diagram of output dependence on free layer thickness.

FIG. 4 is a characteristic diagram of output dependence on spacing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Giant magnetoresistive effect film, 2 ... Lower yoke film, 3 ... Electrode, 4 ... Gap film, 5 ... Upper yoke film, 6 ... High resistivity film, 7 ... Insulating film.

Claims (3)

[Claims] A yoke film also serves as an electrode, and there is no giant magnetoresistive effect film on the sliding surface side. The yoke film is disposed at a distance of 0.5 μm or more from the sliding surface via the yoke film, The element height of the effect film is 5 μm or less, the thickness of the free layer of the giant magnetoresistive film is 10 nm or less, and the spacing of the upper and lower yoke films is 1 μm or more and 10 μm or less. Type magnetic head. The yoke film also serves as an electrode, and there is no giant magnetoresistive film on the sliding surface side. The yoke film is disposed at a distance of 0.5 μm or more from the sliding surface via the yoke film. The element height of the effect film is 5 μm or less, the thickness of the free layer of the giant magnetoresistive film is 10 nm or more, the spacing of the upper and lower yoke films is 1 μm or more and 10 μm or less. A yoke type magnetic head, wherein the gap film between the upper and lower yoke films is a conductive film having a thickness of 0.2 μm or less, and the back contact film is formed of an insulating magnetic film having a specific resistance of 1000 μΩcm or more. 3. A yoke type magnetic head according to claim 1, wherein said yoke film has a thickness of 0.1 μm or more.