JPH05174336A - Magneto-resistance effect type head - Google Patents

Abstract

PURPOSE:To obtain the inexpensive magneto-resistance effect type head having high performance by adding prescribed elements to an NiFe alloy film. CONSTITUTION:An Ni-Fe film is deposited at 1mum as a magnetic shielding film 2 by a sputtering method on a nonmagnetic insulating substrate 1 and is finely worked to a prescribed shape; thereafter, an Al2O3 film which is an insulating film 3 is deposited at 0.2mum thereon and an (Ni-19at.% Fe)-4at.% Ta film is deposited at 50nm thereon. In succession, Al2O3 which is an insulating film 8 is deposited at 20nm and further an Ni-19at.% Fe film which is a magneto-resistance effect film 6 is deposited at 50nm; thereafter, the films are finely worked to a prescribed shape. The compsn. of alloy consists of (M1M2) y.(M3M4)x, where (M1M2) consists of magnetic metal elements M1, M2 and (M3M4) contains Ta, x+y=100%. M3 includes Ta and M4 includes at least one selected from Ti, V, Zr, Hf, Ru, Rh and Cr. As a result, the inexpensive magneto-resistance effect type head having the high performance is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a magnetic recording device.

[0002]

2. Description of the Related Art In a magnetic head using a magnetoresistive type of ferromagnetic material, a linear change portion with respect to the magnetic field of the magnetoresistive effect must be used in order to reproduce an alternating magnetic field from a magnetic recording medium. For this reason, a shunt film, a bias magnetic field applying means is usually provided adjacent to the magnetoresistive film.
A soft magnetic film and a permanent magnet film are installed.

The present invention relates to a magnetoresistive effect element using a soft magnetic film, particularly a magnetoresistive effect element having a cross-sectional structure of crystalline soft magnetic film / spacer metal film / spacer insulating film / magnetoresistive effect film. Of the soft magnetic film. Prior arts relating to this crystalline soft magnetic film include U.S. Pat. No. 4,663,685, Japanese Unexamined Patent Publication (Kokai) No. 3-116510, and Journal of Applied Phy.
sics) 69 (1991) No. 15, pp. 5631-5633.

[0004]

The soft magnetic film used as the bias magnetic field applying means of the magnetoresistive effect element includes:
In addition to the magnetic properties, corrosion resistance, price, and reliability such as variations in magnetic properties and changes with time are also important issues.
Although the conventional NiFe-Rh alloy film is excellent in corrosion resistance and the like, it is necessary to add 20-25 at.% Of expensive Rh to NiFe, and the price as a material is high.

Although the cost of the alloy film in which Nb or Zr is added to NiFe is lower than that of the NiFe-Rh alloy film,
It has the disadvantages of poor corrosion resistance, large variations in magnetic properties, and large changes over time.

Further, in the amorphous magnetic film, the initial layer is easily crystallized when deposited on the substrate, and variations in magnetic characteristics and changes due to heat treatment are very large.

In addition to the magnetic characteristics, the present invention has corrosion resistance, price,
It is intended to solve problems such as variations in magnetic characteristics and reliability such as aging.

[0008]

In order to solve the above problems, the effects of the third element and the fourth element added to the NiFe alloy film are examined, and Ta as the third element and Nb, Ti as the fourth element, V, Zr, Hf, Ru, Rh, Ir, Cr
Was added.

[0009]

The operation of the present invention will be described with reference to FIGS. When Ta is added to the NiFe alloy film, the saturation magnetization of the NiFe alloy film does not deteriorate at all up to about 6 at.% Ta, as shown in Fig. 1, and gradually decreases when it exceeds 6 at.%. To do.

As shown in FIG. 2, the coercive force hardly changes up to the addition amount of Ta of 6 at.%, And it tends to increase when the addition amount exceeds Ta.

The magnetostriction changes to the positive direction as shown in FIG. 3 by the addition of Ta, but the change is large when the addition of Ta is small, and the amount of change at 2 at.% Or more is extremely small.

As shown in FIG. 4, the magnetoresistive effect rate drops sharply by the addition of Ta, and falls to about 1/10 or less of the NiFe alloy film at about 2 at.%.

The resistivity of the alloy film is 2 at. As shown in FIG.
% Ta increases sharply, but beyond this, NiFe
Saturation is reached at about 4-5 times the alloy film. The basic characteristics of the NiFe-Ta alloy film are as described above, and the Ta addition amount is 2 at.
% To 9 at.% Is a region in which the characteristics are extremely stable, and the variation in characteristics of the obtained alloy film is very small. Therefore, this composition region can be used as a bias film of the magnetoresistive element, and the result of the corrosion resistance test under high temperature and high humidity was also superior to that of the conventional alloy. Also, the Ta amount is 1-12a
It can be used even in the range of t.% by adjusting the film thickness of the soft bias type element.

Using a NiFe-Ta alloy film as a basic alloy,
By adding a small amount of Nb, Ti, V, Zr, Hf, Ru, and Rh to this, the characteristics such as the specific resistance required as a soft magnetic film for bias are more suitable without impairing the above advantages of the NiFe-Ta alloy film. Becomes

[0015]

EXAMPLES Details will be described below with reference to examples.

Example 1 A Ta plate having a diameter of 8 mm was stuck on a Ni-19 at.% Fe alloy plate to obtain a NiFe-Ta alloy target. The amount of Ta added was controlled by the number of Ta stuck. This embodiment was adopted to finely change the amount of Ta added, and the same effect can be obtained as a NiFeTa alloy target. Although glass was used for the substrate, this is also the same as long as it is an insulating substrate such as alumina, and a metal thin film or the like may be used. 10 ^-4 P inside the vacuum chamber of the sputtering equipment
Evacuate to a vacuum of a or less, then 5 × 10 ^-1 Pa
Ar gas was introduced so as to keep the above value, and sputtering was performed with an input power of 200W. The film thickness at this time is 5 to 100 nm.

FIG. 1 shows the magnetic characteristics and the magnetoresistive effect characteristics of a NiFe-Ta alloy sputtered film having a film thickness of 50 nm.
The saturation magnetization of the NiFe alloy film was not deteriorated at all up to about 6 at.%, And gradually decreased at 6 at.% Or more, and 0.4 or less at 12 at.% Or more. It becomes lower than the lower limit value (0.4T) used for. As shown in FIG. 2, the coercive force increases considerably when the addition amount of Ta becomes 13 at.% Or more. Magnetostriction is NiFe as shown in FIG.
The value of the basic alloy is −3.5 × 10 ⁻⁷ , and the addition of Ta causes a sharp decrease at first and then a gradual decrease. About 8 at.%
It changes from negative to positive at Ta. However, the amount of change is extremely small, and since it can be used as the bias film if it is ± 10 ⁻⁶ or less, the above composition range is sufficiently practical. As shown in FIG. 4, the magnetoresistive effect rate drops sharply by the addition of Ta, and falls to about 1/10 or less of the NiFe alloy film at about 2 at. The resistivity of the alloy film is 2 at.% As shown in Fig. 5.
Although it rapidly increases up to Ta, it is almost saturated at about 4-5 times that of the NiFe alloy film above this. The basic characteristics of the NiFe-Ta alloy film are as described above. Considering the above characteristics, the range of Ta addition amount from 2 at.% To 9 at. The variation in the characteristics of the film is very small. Also, the Ta amount is 1
Even in the range of -12 at.%, It can be used by adjusting the film thickness of the soft bias type element.

Next, the composition of the NiFe basic alloy is changed to N.
An iFe-Ta alloy film was produced and the NiFe composition dependence was investigated. FIG. 6 shows the relationship of the Ta addition amount when the composition of NiFe is plotted on the horizontal axis and the coercive force is plotted on the vertical axis. The coercive force shows a small change and shows a low value within the range of the Ni content in NiFe up to 79-91 at.%, But increases outside this range. Therefore, the composition of the NiFe basic alloy is preferably 80-82 at.% Ni. FIG. 7 shows the relationship of the Ta addition amount when the composition of NiFe is plotted on the horizontal axis and the magnetostriction is plotted on the vertical axis.
When the Ni content in iFe is within the range of 80-82 at.%, the change is small and shows a low value of 10 ^-6 or less.
It goes up when it goes out of this range. Therefore, from the viewpoint of magnetostriction, the composition of the NiFe basic alloy is 80-82 at.% Ni.
Is desirable.

Example 2 A Ni-19 at.% Fe alloy plate was pasted with a Ta plate and a Nb plate each having a diameter of 8 mm, and NiFe-
It was used as a Ta-Nb alloy target. The amount of Ta and Nb added was controlled by the number of sheets attached. Glass was used for the substrate. The inside of the vacuum chamber of the sputtering apparatus was evacuated to a vacuum degree of 10 ^-4 Pa or less, then Ar gas was introduced so as to maintain 5 × 10 ^-1 Pa, and sputtering was performed with an input power of 200 W.
The film thickness at this time is 5 to 100 nm.

8 and 9 show a NiFe film having a thickness of 50 nm.
Due to the effect of Nb addition on the magnetic characteristics and magnetoresistive effect characteristics of the -5at.% Ru alloy sputtered film, the saturation magnetization of the NiFe alloy film does not deteriorate up to 3at.% Or more until the Nb addition amount reaches about 2at.%. Then it begins to fall sharply. The coercive force gradually decreases until the amount of Nb added reaches 5 at.% And increases when the amount exceeds this level. The magnetostriction of the NiFe-5 at.% Ta basic alloy was -3.3 x 10 ^-8 , and the amount of Nb added was about 2-.
It gradually changes to the positive side up to 3 at.%, And changes significantly to the positive direction when it exceeds 3 at.%. The magnetoresistive effect rate drops sharply by the addition of Nb, and falls to 1/20 or less of the NiFe alloy film at about 0.5 at. The resistivity of the alloy film is 2 at.
% Ta increases rapidly, but beyond this, NiFe-
Saturation is reached at about 2.5 times that of a 5 at.% Ta alloy film. Ni
The basic characteristics of the Fe-Ta-Nb alloy film are as described above.
When the amount of Nb added is 0.5 to 5 at.%, It is a region where the characteristics are stable, and the effect of adding Nb causes the resistance to increase and the magnetoresistive effect rate to decrease remarkably. It has sufficient characteristics as a soft magnetic bias film of the magnetoresistive effect element. Further, the variation in characteristics of the obtained alloy film is very small. Next, as a result of examining the NiFe composition dependency, the Ni content in NiFe was 79-91 at.
Within the range up to%, it shows little change and low value,
The composition of the NiFe base alloy is 79-81 at.% Ni and Ta
Of 2 to 9 at.% And Nb of 0.5 to 5 at.% Have sufficient characteristics as a soft magnetic bias film of the magnetoresistive effect element.

Example 3 As in Example 2, even when Ti was added instead of Nb, the composition of the NiFe basic alloy was 79-81 at.% Ni, Ru was 2-9 at.% And Ti was 0.5. Up to -5 at.%, It has sufficient characteristics as a soft magnetic bias film of the magnetoresistive element.

Example 4 As in Example 2, even when Ir was added instead of Nb, the composition of the NiFe basic alloy was 79-81 at.% Ni, Ta was 2-9 at.% And Ir was 0.5. Up to -5 at.%, It has sufficient characteristics as a soft magnetic bias film of the magnetoresistive element.

Example 5 Similar to Example 2, the composition of the NiFe basic alloy was 7 even when V was added instead of Nb.
9-81 at.% Ni, Ta 2-9 at.%, V 0.5-
Up to 5 at.%, It has sufficient characteristics as a soft magnetic bias film of the magnetoresistive element.

Example 6 Similar to Example 2, even when Zr was added instead of Nb, the composition of the NiFe basic alloy was 79-81 at.% Ni, Ta was 2-9 at.% And Zr was 0.5. Up to -5 at.%, It has sufficient characteristics as a soft magnetic bias film of the magnetoresistive element.

Example 7 Similar to Example 2, even when Ru was added instead of Nb, the composition of the NiFe basic alloy was 79-81 at.% Ni, Ta was 2-8 at.% And Ru was 1-5 at. Up to.%, It has sufficient characteristics as a soft magnetic bias film of the magnetoresistive effect element.

Example 8 Using the crystalline soft magnetic film described in Examples 1 to 7, a magnetoresistive head having the structure shown in FIG. 10 was produced. First, a Ni—Fe film is deposited as a magnetic shield film 2 on the non-magnetic insulating substrate 1 by a 1 μm sputtering method, finely processed into a predetermined shape, and then an Al ₂ O ₃ film 3 which is an insulating film is deposited by 0.2 μm. , On top of this (Ni-1
9 at.% Fe) -5 at.% Ta film 4 is deposited to 50 nm, Nb-10 at.% Ta alloy film 5 which is a high specific resistance metal is subsequently deposited to 10 nm, and subsequently a magnetoresistive film 6 is made to be Ni-19 at. After depositing a 50% Fe 2 film by 50 nm, the electrode 7 was formed by microfabrication into a predetermined shape. Next, an Al ₂ O ₃ film 8 as an insulating film was deposited to a thickness of 0.2 μm, and a Ni—Fe film as a magnetic shield film 9 was deposited thereon by a sputtering method of 1 μm. An Al ₂ O ₃ film was further deposited thereon to a thickness of 2 μm, and then an inductive thin film head for recording was formed. When the recording / reproducing characteristics were measured using this head and a Co-Pt-Cr sputter medium, it was about 8 times as high as the output of a shunt bias type magnetoresistive head using Nb or Ti film as a bias film. A playback output was obtained.

FIG. 11 shows a reproduction output waveform obtained by the head of this embodiment. FIG. 12 shows the relationship between the device current and the bias magnetic field. The bias magnetic field is sufficiently applied from the region where the device current is low. Since the magnetoresistive effect element can control the electric resistance of the film forming the element to a constant value, it can be driven with a constant current.

Example 9 A magnetoresistive head having a structure shown in FIG. 10 was produced using the crystalline soft magnetic film described in Examples 1 to 7. First, a Ni—Fe film as a magnetic shield film is deposited on a non-magnetic insulating substrate by a 1 μm sputtering method, finely processed into a predetermined shape, and then an insulating film A is formed.
An l ₂ O ₃ film is deposited to a thickness of 0.2 μm, and (Ni-19a
t.% Fe) -4 at.% Ta film is deposited to a thickness of 50 nm, then an Al ₂ O ₃ film that is an insulating film is deposited to 20 nm, and then a Ni-19 at.% Fe film that is a magnetoresistive film is deposited to 50 n.
After being deposited, it was finely processed into a predetermined shape. The subsequent steps were the same as in Example 8 to form a recording / reproducing head.
When the recording and reproducing characteristics were measured using this head and a Co-Pt-Cr sputter medium, the output was about 10 times that of the shunt bias type magnetoresistive head using Nb or Ti film as the bias film. A playback output was obtained. The difference from Example 8 is that the element current shunted to the soft magnetic film became zero as a result of separating the soft magnetic film and the magnetoresistive effect film by the insulating film, so that the output increased by this shunt current.

Example 10 In the magnetic head in which the structure of the magnetoresistive element is a NiFe magnetoresistive film / spacer metal film / soft magnetic bias film in this order from the substrate side, the same results as in Examples 8 and 9 are obtained. was gotten.

Example 11 In the magnetoresistive head having the same structure as in Examples 8, 9 and 10, the magnetoresistive film may be a Co / Cu superlattice film which is a giant magnetoresistive film. The output was increased by about one digit as compared with the shunt bias type head using Nb for the shunt film.

Embodiment 12 In the magnetoresistive head having the same structure as in Embodiments 8, 9 and 10, the magnetoresistive film is a giant magnetoresistive film of NiFe / Cu.
Even when the superlattice film is used, the output is increased by about one digit as compared with the shunt bias type head using Nb for the shunt film.

Example 13 In the magnetoresistive head having the same structure as in Examples 8, 9 and 10, the magnetoresistive film was a giant magnetoresistive film of NiFe / Cu.
Even when the / Co superlattice film is used, the output is increased by about one digit as compared with the shunt bias type head using Nb for the shunt film.

Example 14 In the magnetoresistive head having the same structure as in Examples 8, 9 and 10, the magnetoresistive film was a giant magnetoresistive film of NiFe / Ag.
Even when the superlattice film is used, the output is increased by about one digit as compared with the shunt bias type head using Nb for the shunt film.

Fifteenth Embodiment In the magnetoresistive head having the same structure as in the eighth, ninth and tenth embodiments, the thickness of the magnetoresistive film is changed to 5-80 nm so that the optimum bias can be obtained. Similar results were obtained with a head manufactured by changing the thickness of the soft magnetic film to 2-90 nm. The thickness of the magnetoresistive film is 5 nm or less and 60 nm
If it is above, noise increases, so 5-60 nm is preferable. In this case, since the magnetic anisotropy of the magnetoresistive film changes depending on the thickness, the thickness of the soft magnetic film must be determined so as to have the optimum bias. FIG. 13 shows an example of the relationship between the thickness of the magnetoresistive film and the soft magnetic film for obtaining the optimum bias.

Example 16 In order to examine the corrosion resistance of the soft magnetic films shown in Examples 1 to 7, the magnetic properties were measured by leaving them in an environment of 90% relative humidity and 80 ° C. temperature. FIG. 14 shows the relationship between the saturation magnetization and the film composition of a typical sample after leaving for 3000 hours.
It can be seen that the addition of 2 at.% Ta reduces the saturation magnetization less than that of the e film, and that the addition of Ta improves the corrosion resistance. The corrosion resistance of the film in which Nb or the like is added as the fourth element in addition to Ta is slightly inferior to the film in which Ta alone is added.
It is superior to the 19 at.% Fe film. When Ru, Rh, Ir and Cr are added as the fourth element, the corrosion resistance is further improved. In the magnetic head, the cross section of the element is exposed on the medium facing surface. Therefore, with respect to the head in this state as well, the change in reproduction output was measured after being left in the above atmosphere for 3000 hours, but there was no output fluctuation or noise increase. Not observed.

[0036]

The (Ni-Fe) -Ta film and the (Ni-Fe) -T film which are magnetically high in performance, excellent in corrosion resistance, and low in cost.
By applying aM (M: fourth element) as a soft magnetic film for applying a bias magnetic field of a magnetoresistive head, it is possible to provide a high-performance and inexpensive magnetoresistive head.

[Brief description of drawings]

FIG. 1 is a graph showing an embodiment of the present invention.

FIG. 2 is a graph showing an embodiment of the present invention.

FIG. 3 is a graph showing an embodiment of the present invention.

FIG. 4 is a graph showing an embodiment of the present invention.

FIG. 5 is a graph showing an embodiment of the present invention.

FIG. 6 is a graph showing an example of the present invention.

FIG. 7 is a graph showing an example of the present invention.

FIG. 8 is a graph showing an example of the present invention.

FIG. 9 is a graph showing an embodiment of the present invention.

FIG. 10 is a graph showing a cross section of a head according to an embodiment of the present invention.

FIG. 11 is a graph showing an example of the present invention.

FIG. 12 is a graph showing an example of the present invention.

FIG. 13 is a graph showing an example of the present invention.

FIG. 14 is a graph showing an example of the present invention.

[Explanation of symbols]

1 ... Non-magnetic substrate, 2, 9 ... Magnetic shield film, 3, 8 ... Insulating film, 4 ... Soft magnetic film, 5 ... Spacer metal film, 6 ... Magnetoresistive film, 7 ... Electrode.

Claims (10)

[Claims] 1. An alloy composition of (M ₁ M ₂ ) y · (M ₃ M ₄ ) and (M ₁ M ₂ ) of magnetic metal elements M ₁ and M ₂ .
(M ₃ M ₄ ) contains Ta, x + y = 100%, the content x is 2-9 at.%, And the crystalline soft magnetic film characterized by containing incidental incidental impurities is used as a bias film. A magnetoresistive head characterized by being used. 2. In claim 1, M ₃ is Ta and M ₄ is N.
At least one selected from b, Ti, V, Zr, Hf, Ru, Rh, and Cr has a relation of x = x ₃ + x ₄ (x ₃ > x ₄ ), and x ₃ is M ₃ (= Ta) Content of 2-9 at.%,
0.5-5at x ₄ is at a content of M _4.%, x is 2-14a
A magnetoresistive effect head characterized by using a crystalline soft magnetic film characterized by being t.%. 3. An alloy film according to claim 1 or 2 is used as a soft magnetic film of a magnetoresistive effect element having a sectional structure of a soft magnetic film / spacer metal film / magnetoresistive effect film. A magnetoresistive head. 4. The alloy film of claim 1 or 2 is used as a soft magnetic film of a magnetoresistive effect element having a cross-sectional structure of a soft magnetic film / spacer insulating film / magnetoresistive effect film. A magnetoresistive head. 5. The method according to claim 3 or 4, wherein (M ₁ M
₂ ) is a NiFe alloy film, the composition of which is Ni-18 at.% F
e to Ni-20 at.% Fe. Magnetoresistive head. 6. The magnetoresistive film according to claim 3 or 4, wherein the magnetoresistive film includes an atomic layer made of 1-3 elements of Ni, Co, and Fe, and an atom containing atoms made of Au, Ag, Cu, Cr. A magnetoresistive head comprising a multi-layered magnetoresistive film with a layer. 7. The magnetoresistive head according to claim 3 or 4, wherein a soft magnetic film / spacer metal film / magnetoresistive film and a soft magnetic film / spacer insulating film / magnetoresistive film are provided with an insulating film interposed therebetween. A magnetoresistive head having a structure in which is sandwiched between magnetic shield films. 8. A magnetoresistive head, wherein the soft magnetic film used in the magnetoresistive head according to claim 1 has a thickness of 10 to 70 nm. 9. A magnetoresistive head, wherein the magnetoresistive head according to any one of claims 3 to 8 is used as a reproducing head and is combined with an inductive head for recording. .. 10. A magnetic memory device comprising the magnetoresistive head according to claim 3 driven at a constant voltage.