JPH07302411A - Magnetoresistive magnetic head - Google Patents

Abstract

(57) [Abstract] [Purpose] Even with a thin magnetic domain control layer, a longitudinal bias is sufficiently generated in the magnetic sensitive portion of the magnetoresistive film, Barkhausen noise is completely suppressed, and a highly sensitive and reliable magnetic field is obtained. A resistance effect magnetic head is provided. A magnetoresistive effect film 70 for electrically converting a magnetic signal, a pair of electrodes for supplying a signal detection current to the magnetoresistive effect film 70, and a magnetoresistive effect film 70 magnetically extending in the longitudinal direction. A magnetic domain control layer for applying a bias, a soft film 40 for applying a lateral bias to increase the sensitivity of the magnetoresistive effect film 70, a magnetoresistive effect film and a soft film 4.
In the magnetoresistive effect type magnetic head having a separation film for electrically and magnetically isolating 0 from each other, the magnetoresistive effect film 70 and the soft film 40 are formed substantially only in the central magnetic sensitive region, The planar film 50 is provided in close contact with the edge of the magnetic sensitive portion in the end region, and the magnetoresistive film 70 is formed on the soft film 40 and the flat separation film on the planar film 50.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetoresistive effect type magnetic head utilizing the magnetoresistive effect used in magnetic recording devices such as magnetic disk devices and magnetic tapes.

[0002]

2. Description of the Related Art The main problem of a magnetoresistive head is that when a magnetoresistive film has a domain wall, the magnetic field irregularly moves due to a signal magnetic field from the magnetic surface of a magnetic recording medium, causing Barkhausen. The noise is called noise. Therefore, it is necessary to eliminate the domain wall of the magnetoresistive film.

As a method of eliminating the domain wall of the magnetoresistive effect film, as shown in FIG. 2 (a), the magnetoresistive effect element disclosed in US Pat. A magnetic domain control layer composed of a ferromagnetic material is installed,
The exchange coupling generated between the antiferromagnetic material and the magnetoresistive film is used. This is because the longitudinal bias is generated only at both ends of the magnetoresistive film to keep the regions at both ends in the single magnetic domain state, so that the magnetic sensitive region in the center of the magnetoresistive film is also brought into the single magnetic domain state. Induce.

In US Pat. No. 5,050,096, hard magnetic bias layers are provided at both upper ends of the magnetoresistive film with a spacer interposed therebetween, and the ends are formed by exchange coupling between the hard magnetic bias layer and the magnetoresistive film. A magnetoresistive effect element having a longitudinal bias generated only in a region is described. The spacer material proposed in this patent is Cr, Ti, Nb, W
The material of the hard magnetic bias layer is CoNiCr, CoC.
It is a Co alloy having special characteristics such as r and CoPtCr.

In both of the above patents, the longitudinal bias is generated only in the end region of the magnetoresistive effect film, and only the lateral bias is generated in the central magnetic sensitive portion.
A magnetic domain wall was formed between the magnetic sensitive region and the end region, and Barkhausen noise could not be completely suppressed.

In addition, US Pat.
As shown in (b), the magnetoresistive effect film is provided substantially only in the central magnetic sensitive part region, and the hard magnetic bias layers are adhered to the edges of the magnetic sensitive part at both ends of the magnetoresistive effect film. And a magnetoresistive effect element for generating a longitudinal bias in the magnetic sensitive portion of the magnetoresistive effect film.

[0007]

The magnetoresistive effect element disclosed in US Pat. No. 5018037, as shown in FIG. 2B, generates a longitudinal bias in the magnetic sensitive portion of the magnetoresistive effect film. Therefore, in the future, when the track width becomes narrower as the recording density is improved, an excessive amount of magnetic flux is generated in the magnetoresistive film, and therefore the amount of magnetic flux coming from the magnetic domain control layer is minimized to be undesirably thin. A magnetic domain control layer must be used. However, unless the magnetic domain control layer is formed on the entire edge of the magneto-sensitive film of the magneto-resistive film, sufficient longitudinal bias is not generated in the magneto-resistive film, and Barkhausen noise cannot be completely suppressed. . In addition, there is a problem in terms of reliability, since the step difference at the end of the magnetoresistive film is large and contact failure easily occurs at the junction between the magnetoresistive film and the magnetic domain control layer.

An object of the present invention is to propose a structure in which even in a thin magnetic domain control layer, a longitudinal bias is sufficiently generated in the magnetic sensitive portion of the magnetoresistive film to completely suppress Barkhausen noise. .

[0009]

The gist of the present invention for solving the above problems is as follows. That is, the magnetoresistive effect magnetic head of the present invention includes a magnetoresistive effect film for electrically converting a magnetic signal using the magnetoresistive effect, and a pair of electrodes for passing a signal detection current through the magnetoresistive effect film. A magnetic domain control layer for magnetically applying a longitudinal bias in the longitudinal direction to the magnetoresistive film, a soft film for applying a lateral bias to increase the sensitivity of the magnetoresistive film, and A magnetoresistive film and a soft film are electrically and magnetically separated from each other, and the magnetoresistive film and the soft film are formed substantially only in the central magnetic sensitive region, and the end of the soft film is formed. The planar film extends in close contact with the edge of the magnetic sensitive portion on one of the regions to form a separation film flat on the soft film and the planar film, and the magnetic sensitive portion is formed on one of the end regions of the magnetoresistive film. The magnetic domain control layer extends in close contact with the edge of the Wherein the generating a longitudinal bias in sensitive portion of Hatemaku.

The planar film is made of Ti, Ta, C.
Any metal material of r, C, Nb, Mo and W, A
1 ₂ O ₃ , SiO ₂ , TiO ₂ , or ZrO ₂ , or an insulating material formed by adding a third element to the insulating film, and the thickness thereof is 0.01 μm to 0 μm. .0
It is preferably 3 μm.

Further, the separation film provided on the soft film and the planar film is made of Al ₂ O ₃ , SiO ₂ , TiO ₂ , Z.
The insulating film is made of any one of rO ₂ or an insulating material formed by adding a third element to the above insulating film, and its film thickness is preferably 0.01 μm to 0.05 μm.

[0012]

According to the present invention, the magnetoresistive effect film can be formed on the flat separation film by forming the planar film in the end region of the soft film, and the magnetoresistive effect type magnetic head with high sensitivity and high reliability can be obtained. Can be produced. Also, since the step difference at the end of the magnetoresistive effect film is reduced, the adhesion between the magnetic domain control layer and the junction of the magnetoresistive effect film is improved, and further, the magnetic domain control layer is formed on the entire edge of the magnetic sensitive part of the magnetoresistive effect film. Can be formed, so that Barkhausen noise can be completely suppressed and a highly reliable head can be manufactured.

Further, according to the present invention, by using the insulating film as the separation film on the soft film, the shunt ratio of the magnetoresistive film is improved and a highly sensitive magnetoresistive head can be manufactured.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the magnetoresistive effect magnetic head of the present invention will be described with reference to the sectional view of the magnetoresistive effect magnetic head of FIG.

The magnetoresistive head is a lower shield film 20 formed on a non-magnetic ceramic substrate 10.
And the lower gap film 30 on the lower shield film 20.
It has and. Soft film 4 on the bottom gap film 30
0, the planar film 50 is formed in the end region of the soft film 40. A separation film 60 for separating the soft film and the magnetoresistive effect film is formed on the soft film 40 and the planar film 50, and a magnetoresistive effect film 70 is formed only on the central magnetic sensitive region. . On one of the end regions of the magnetoresistive film 70, the magnetic domain control layer 80 that is in close contact with the edge 3 of the magnetic sensing part of the magnetoresistive film 70, the signal reading electrode 90 further thereon, and so as to cover the same. Upper gap film 10
0, an upper magnetic shield film 110 and a protective film 120. The function and material of each layer and each film will be described below.
Upper magnetic shield film 110 and lower magnetic shield film 20
Serves to prevent the magnetic resistance effect film 70 from being affected by a magnetic field other than a signal and to enhance the signal resolution of the magnetoresistive effect type magnetic head. The material is a NiFe alloy, a NiCo alloy, or a FeSiAl alloy, and the film thickness of these is about 0.5 to 3.0 μm.

The upper gap film 100 and the lower gap film 30 arranged adjacent to the magnetic shield films 110 and 20.
Is the magnetoresistive film 70 and the upper magnetic shield film 110.
Also, it acts to electrically and magnetically isolate the lower magnetic shield film 20, and is made of glass, Al ₂ O ₃ or other non-magnetic insulator. Since the film thicknesses of the upper and lower gap films 100 and 30 affect the reproduction resolution of the magnetoresistive head.
It is usually in the range of 0.1 to 0.4 μm depending on the recording density desired for the magnetic disk device.

The soft film 40 has a function of applying a lateral bias in order to increase the sensitivity of the magnetoresistive effect film 70.
The material is NiFeNb, NiFeZrO ₂ , NiFe.
Rh and NiFeCo are used, and the film thickness is 0.01 to 0.0.
It is 05 μm.

The material of the planar film 50 is Ti, Ta, C.
Al as the metal film and insulating film of r, C, Nb, Mo, W
₂ O ₃ , SiO ₂ , TiO ₂ , and ZrO ₂ are preferable. Alternatively, the insulating film may be formed by adding a third element.

The separation film 60 has a function of magnetically separating the magnetoresistive film 70 and the soft film 40, and the soft film 40 and the magnetic domain control layer 80. The material is Al ₂ O ₃ , Si
An insulating material such as O ₂ , TiO ₂ , or ZrO ₂ or a material obtained by adding a third element to the insulating material is used, and its film thickness is 0.0
It is 1 to 0.05 μm.

The magnetoresistive film 70 is made of NiFe alloy, Ni
A ferromagnetic film, such as a Co alloy or a NiFeCo alloy, whose electric resistance changes depending on the direction of magnetization is used. The film thickness is 0.01 to 0.04 μm.

The magnetic domain control layer 80 has a function of applying a longitudinal bias in the lengthwise direction to bring the magnetoresistive film 70 into a single magnetic domain state. The material is CoPt, CoCrPt, CoCr
A hard magnetic material such as Ta is used, and the film thickness is 0.01 to
It is 0.04 μm.

The signal detecting electrode 90 is a magnetoresistive film 70.
Sufficient current, for example 1 × 10 ^{6 to} 20 × 10 ⁶ A / cm
^{Since 2} flows, Au, Nb, T, which usually have low electrical resistance
A single layer or a laminated film of a, Cu, W or the like is used.

Next, a method of manufacturing the magnetoresistive head of the present invention will be described. As the thin film forming method and patterning method described below, well-known techniques such as a sputtering method, an ion milling method, and an etching method were used. Figure 4
(A)-(d) and FIG. 5 (a)-(d) show the soft film 4.
0 and a specific embodiment for making the planar film 50 is shown.

First, a lower magnetic shield film 20 made of NiFeN is formed on the substrate 10 to a thickness of 1 μm, and a lower gap film 30, for example, an Al ₂ O ₃ film is formed thereon to a thickness of 0.1 μm or more. Conventionally, as shown in FIG. 3B, a soft film, a shunt film, and a magnetoresistive effect film are continuously formed and patterned to form a magnetoresistive effect layer, and then a permanent magnet such as a CoCrPt film which is a magnetic domain control layer. Had formed a film. According to the present invention, as shown in FIG. 4, 0.02 μm of NiFeNb to be the soft film 40 is formed on the lower gap film 30 and is patterned so as to remain in the region corresponding to the magnetic sensitive portion 85 (see FIG. )). Next, the planar film 50, for example, Al ₂
The O ₃ film has at least the same thickness as the soft film 40, 0.02 μm.
The above is formed (FIG. 4B), and the photoresist film 55 is formed thereon.
Are formed to be flat (FIG. 4C). The thickness of the photoresist film 55 is about 0.08 μm on the soft film 40.
Is. After that, it is processed into a predetermined thickness by the ion milling method (FIG. 4D). At this time, the milling rates of the Al ₂ O ₃ film and the photoresist film are about the same, and the NiFeN film
The milling conditions must be selected so that the milling rate of the b film is slower than that of the Al ₂ O ₃ film and the photoresist film.

Table 1 shows the influence of the reaction gas on the milling rate of the Al ₂ O ₃ film, the photoresist film and the metal film (NiFe).

[0026]

[Table 1]

In a pure Ar gas atmosphere, the milling rate ratio of the Al ₂ O ₃ film, the photoresist film and the NiFe film is 2.6: 1: 0.2 with the photoresist film rate being 1. When CHF ₃ gas is mixed with Ar gas, the rate of Al ₂ O ₃ film becomes slower, while the photoresist film and NiFe
The rate of the film is increased to 2.1: 1: 0.8 with 70% CHF ₃ mixed gas. CHF ₃ gas to Ar gas 8
When 5% is mixed, the rates of Al ₂ O ₃ film and photoresist film are almost the same, and NiFe film is about 20% compared to both.
Turns out to be slow. In addition, the milling rate ratio in the CF ₄ gas atmosphere was 1.2: 1: 0.3, and the rates of the Al ₂ O ₃ film and the photoresist film were almost the same as in the 85% CHF ₃ mixed gas, and the milling of the NiFe film was performed. It can be seen that the speed is about 30% of both. From this result, Al ₂
Al ₂ O produced by the method of this embodiment using an O ₃ film
It is understood that the ₃ film and the photoresist film may be milled in an Ar gas + 85% CHF ₃ gas or CF ₄ gas atmosphere.

FIG. 6 shows a planar film 5 which is a feature of the present invention.
The film thickness of 0, the bias magnetic field of the magnetoresistive film, and the full width at half maximum of the ΔV-H curve and the ΔV-H curve are shown. When the planar film is thinner than the soft film, the bias magnetic field is about 35O.
e, the bias magnetic field increases to about 50 Oe when the planar film is thick and the soft film is thicker than the soft film. But,
The full width at half maximum of the ΔV-H curve increases with the planar film thickness, and the anisotropic magnetic field of the magnetoresistive effect film increases, leading to a reduction in reproduction output. On the other hand, Barkhausen noise
Although it occurs when the planar film is thinner than the soft film, it can be seen that the planar film is suppressed at the same thickness (20 nm) as the soft film. This is because the position where the CoCrPt film is formed changes depending on the thickness of the planar film. From this result, it is understood that the desirable thickness of the planar film is 0.01 to 0.03 μm, which is almost the same as the soft film.

Next, another embodiment shown in FIG. 5 will be described. First, NiFeNb, which is the soft film 40, is formed on the lower gap film 30. Next, a film of an appropriate material such as photoresist is formed to an appropriate thickness, for example, 0.1 μm, and the photoresist film is patterned so as to remain only in the magnetic sensitive portion (FIG. 5A). The soft film 40 is patterned by the ion milling method and the etching method (FIG. 5).
(B)). After that, an Al ₂ O ₃ film which is a planar film is formed (FIG. 5C), and the Al ₂ O ₃ film on the photoresist film is removed together with the photoresist film by a lift-off process (FIG. 5D).

A first isolation film 60, for example, an Al ₂ O ₃ film is formed at a predetermined position in a thickness of 0.02 μm on the soft film 40 and the planar film 50 produced by this method. Further, as the magnetoresistive effect film 70, a NiFe film is formed with a thickness of 0.02 μm. Similar to the manufacturing method shown in FIG. 5, the photoresist film is set to 0.1 μm.
m, and patterned so as to remain only in the magnetic sensitive region 1. After that, the magnetic domain control layer 80, for example, C
An oCrPt film is formed, an electrode 90 is further formed, and the CoCrPt film and the electrode film on the photoresist film are removed together with the photoresist film by a lift-off process. Here, the magnetic domain control layer 80 may use Cr, Ta, W, Au or the like as a lower layer or an upper layer. Further, the film thickness of the magnetic domain control layer 80 is given by a desired amount of magnetization ratio with the magnetoresistive effect film 70.

Finally, the formation of the upper gap film 100 and the upper magnetic shield film 110 completes the manufacture of the magnetoresistive head of the present invention.

[0032]

The planar film is formed in the end region of the soft film, the isolation film is flatly formed on the planar film, and then the magnetoresistive film and the magnetic domain control layer are formed. The step difference becomes small, and even in a thin magnetic domain control layer, a sufficient longitudinal bias can be generated in the magnetic sensitive portion of the magnetoresistive effect film, and Barkhausen noise can be completely suppressed. As a result, a highly reliable magnetoresistive effect magnetic head could be manufactured.

Further, by using the insulating film as the separation film, the shunt ratio between the magnetoresistive effect film and the soft film was improved, and a highly sensitive magnetoresistive effect film could be manufactured.

[Brief description of drawings]

FIG. 1 is a sectional view of a magnetoresistive effect element according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional magnetoresistive effect element.

FIG. 3 is a sectional view of a magnetoresistive head according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a method for manufacturing a soft film and a planar film.

FIG. 5 is an explanatory view of a method for manufacturing a soft film and a planar film.

FIG. 6 is a bias magnetic field depending on the thickness of the planar film, ΔV−
Explanatory drawing of the change of the half-value width of H curve and (DELTA) V-H curve.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Magnetic sensitive area, 2 ... end area, 3, 4 ...
40 ... Soft film, 50 ... Planar film, 60 ... First separation film, 70 ... Magnetoresistive film, 80 ... Magnetic domain control layer.

Claims (4)

[Claims] 1. A magnetoresistive effect film for electrically converting a magnetic signal using a magnetoresistive effect, a pair of electrodes for flowing a signal detection current through the magnetoresistive effect film, and the magnetoresistive effect film. A magnetic domain control layer for magnetically applying a longitudinal bias in the longitudinal direction, a soft film for applying a lateral bias to increase the sensitivity of the magnetoresistive film, the magnetoresistive film and the soft film. In a magnetoresistive effect type magnetic head having a separation film that electrically and magnetically isolates from each other, the magnetoresistive effect film and the soft film are formed substantially only in the central magnetic sensitive region, and the end of the soft film is formed. The planar film extends in close contact with the edge of the magnetic sensitive portion on one of the partial regions to form the separation film flat on the soft film and the planar film, and further to form an end region of the magnetoresistive film. On the other hand, on the edge of the magnetic sensing A magnetoresistive effect magnetic head, wherein the magnetic domain control layer extends in close contact with the magnetoresistive effect film to generate a longitudinal bias in the magnetically sensitive portion of the magnetoresistive effect film. 2. The planar film according to claim 1, wherein the planar film is T
A metal material selected from i, Ta, Cr, C, Nb, Mo and W, an insulation material selected from Al ₂ O ₃ , SiO ₂ , TiO ₂ and ZrO ₂ or the above-mentioned insulation film. A magnetoresistive effect magnetic head made of an insulating material formed by adding three elements. 3. A magnetoresistive head according to claim 1, wherein the planar film has a thickness of 0.01 μm to 0.03 μm. 4. The separation film provided on the soft film and the planar film according to claim 1, wherein the separation film is Al ₂ O ₃ , Si.
Insulating material of any one of O ₂ , TiO ₂ and ZrO ₂ ,
Alternatively, a magnetoresistive effect magnetic head made of an insulating material formed by adding a third element to the insulating film, and having a film thickness of 0.01 μm to 0.05 μm.