JP3265078B2 - Thin film magnetoresistive head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite thin film MR effect type magnetic head having a magnetoresistive effect element for reproduction and an electromagnetic induction type element for recording, and a hard disk drive device capable of ultra-high density recording it is relates to a thin film magnetoresistive heads used in that HDD device).

[0002]

2. Description of the Related Art In recent years, demands for miniaturization and large capacity of HDDs as magnetic storage devices have been rapidly increasing. Accordingly, there is an urgent need to improve the recording density of magnetic disks and magnetic heads used in HDD devices. In order to increase these capacities, it is necessary to increase the track density, increase the linear recording density, optimize the modulation method, and so on. For this reason, the magnetic disk has a high coercive force and a high residual magnetic flux density. Metal thin-film disks having characteristics of low noise have been developed, and as magnetic heads, metal-in-gap heads, thin-film heads, and laminated magnetic heads in which metal magnetic films have been laminated have been developed.

All of these magnetic heads are called inductive heads utilizing an electromagnetic induction phenomenon, and the reproduction output is proportional to the relative speed between the magnetic head and the magnetic disk. Therefore, when the magnetic disk becomes smaller and the diameter of the reproduction track becomes smaller, the relative speed between the magnetic head and the magnetic disk becomes lower, and as a result, a sufficient reproduction output cannot be obtained. To solve these problems, Japanese Unexamined Patent Publication No. Hei 4-137221 discloses a thin film M which senses magnetic flux from a magnetic disk by utilizing a magnetoresistance effect.
An R effect type magnetic head is disclosed. By using a thin film MR effect type magnetic head, a high output can be obtained without depending on the medium speed, and a higher track density can be obtained.

However, the thin-film MR effect type magnetic head is unique to the thin-film MR effect type magnetic head which does not have a conventional inductive head, such as Barkhausen noise, left-right asymmetry in off-track characteristics, and amplitude asymmetry in reproduced waveform. It became clear that it had the problem of. Problems peculiar to the thin-film MR effect type magnetic head are described in, for example, Joseph SS. I.E.E.E. Transaction of Magnetics, Vol. 28, March 1992, pp. 1031-1037, by Joseph S. Feng (IEEE Trans. Mag. V.
ol. 28. March (1992) pp1031
1037), it is pointed out that the left-right asymmetry of the off-track characteristic strongly depends on the shape such as the height of the MR element.
Also, in this document, the amplitude asymmetry of the reproduced waveform affects the height of the magnetoresistive element and the positional relationship between the upper and lower shields and the magnetoresistive element disposed above and below the magnetoresistive element via an insulating layer. Point out that

[0005] Further, the left-right asymmetry of the off-track characteristic is described by A. Wallash, M. Salo (A. Wallas)
h. Salo) et al., Journal of Applied Physics, vol. 69, no. 8,15 April 19
91, pp. 5402-5404 (J. App.
l. Phys. Vol. 69, no. 8,15 Ap
ril (1991) pp5402-5404) and the like, it is known that it strongly depends on the shape such as the height of the magnetoresistive element portion.

[0006] G. A. Gipson (GA Gi)
bson) et al., IEE Transactions of Magnetics, Vol. 5
September 1992 (IEEE Trans. Ma
g. , Vol. 28, No. 5, September
1992) reports that a negative sensitivity region exists at one end of the magnetoresistive element portion of the thin film MR effect type magnetic head. However, there is no clear discussion of the relationship between this negative sensitivity distribution and off-track characteristics, and the cause and countermeasures for the problem that a reproduced signal having a polarity opposite to the original signal is generated on one side of the off-track characteristics. No clear discussion has been found yet, and there is no suggestion as to how to solve these problems in practice.

Further, the product of the thickness of the soft magnetic film and the saturation magnetization (B
sdSAL) and the ratio (B sdSAL / B sdM) of the product of the film thickness of the magnetoresistive effect film and the saturation magnetization (B sdMR).
R) discloses various techniques for suppressing a bias angle of a magnetoresistive element portion by a soft magnetic film to optimize sensitivity, linear response, Barkhausen noise suppression, and the like in head reproducing characteristics. For example, Japanese Patent Application Laid-Open No. 62-184616
In the publication, the bias angle is 45 degrees, that is, the B
sdSAL / B sdMR ratio is 1 / √2 (about 70%)
Is optimal in terms of sensitivity and linear response, and JP-A-64-76415 discloses that the BsdSAL /
He points out that the range where the BsdMR ratio is 60% or more and 90% or less is the optimum range from the viewpoint of suppressing Barkhausen noise. Further, in JP-A-3-116510, the ratio of B sdSAL / B sdMR is 51.3% or more and 5%.
It is disclosed that a range of 8.8% or less is an optimum range from the viewpoint of Barkhausen noise suppression. However, these documents do not discuss the relationship between off-track characteristics and the bias angle or the B sdSAL / B sdMR ratio, and do not discuss any optimal bias conditions for improving off-track characteristics and increasing track density. It has not been given or suggested.

[0008]

However, the thin film MR
The problems of the left-right asymmetry of the off-track characteristic and the reproduction output of the opposite polarity which occurs on one side of the off-track characteristic, which are peculiar to the effect type magnetic head, must be solved in order to improve the track density. Another problem is that the recording density of the HDD device is still insufficient.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and makes the reproduction sensitivity distribution in the track width direction of the magnetic flux detector uniform, reduces the left-right asymmetry of the off-track characteristic, and reduces the off-track characteristic to one side. An extremely high track density can be achieved by reducing the generated reverse-polarity reproduction output, and the thin film M having excellent off-track characteristics as a servo signal for highly accurate track positioning.
R-type magnetic head, and a thin-film magnetoresistive head having excellent off-track characteristics.
The purpose is to provide

[0010]

In order to achieve this object, a thin film MR effect type magnetic head of the present invention and an HDD device using the thin film MR effect type magnetic head are constituted as follows.

The thin film magnetoresistive head according to claim 1 includes a soft magnetic layer laminated on one surface of the magnetoresistive layer or via a non-magnetic insulating layer, and a current flowing through the magnetoresistive layer. Wherein the soft magnetic layer is magnetized to apply a bias magnetic field to the magnetoresistive layer by the magnetization, wherein the product of the thickness of the soft magnetic layer and the saturation magnetization is and have a construction thickness of resistive layer is 30% to 50% of the product of the saturation magnetization.

Here, if the ratio of the product of the thickness of the soft magnetic layer and the saturation magnetization is less than 30%, the linear response and the reproduction sensitivity tend to be deteriorated, which is preferable. If it exceeds 50%, the lateral symmetry of off-track characteristics tends to deteriorate, which is not preferable. If the bias angle is less than 17 °, the linear response and the read sensitivity tend to deteriorate, and if it exceeds 30 °, the uniformity of the read sensitivity distribution in the track width direction of the magnetic flux detector tends to deteriorate, which is preferable. Absent.

If A Asym is less than -10%, linear response and reproduction sensitivity tend to deteriorate, and if it exceeds 0%, the uniformity of reproduction sensitivity distribution in the track width direction of the magnetic flux detector deteriorates. As a result, the lateral symmetry of the off-track characteristic tends to deteriorate, which is not preferable. The product Br · δ of the residual density (Br) and the film thickness (δ) of the magnetic recording layer of the magnetic recording medium is 185 [Gauss · μm] or less to 120.
[Gauss · μm] is preferable. Br · δ is 185
When the value exceeds [Gauss · μm], the amplitude vertical asymmetry tends to deteriorate.
m] is not preferable because the reproduction output is reduced.

[0014]

According to this structure, the ratio of the product of the thickness of the soft magnetic layer and the saturation magnetization is 30.
% To 50% or the bias angle can be set to 17 ° to 30 °, so that the left-right asymmetry of off-track characteristics can be significantly reduced and the reproduction output of the opposite polarity generated on one side of the off-track can be reduced. . By setting the amplitude vertical asymmetry (A Asym) to -10% to 0%, the left-right asymmetry of off-track characteristics can be significantly reduced, and the reproduction output of reverse polarity generated on one side of off-track can be reduced. it can. Further, residual magnetic flux density (Br) × film thickness of magnetic recording layer (δ) ≦ 185
[Gauss μm] magnetic recording medium and thin film M of the present invention
By using the HDD device in which the R effect type magnetic head is combined, a high track density can be achieved, and the deterioration of the reproduction sensitivity can be extremely reduced.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
I will explain while. FIG. 1 shows a thin film according to an embodiment of the present invention.
FIG. 3 is an enlarged view of a main part of an MR element part of a film MR effect type magnetic head.
FIG. 2 shows a thin film MR effect type magnet according to an embodiment of the present invention.
FIG. 3 is an enlarged perspective view of a main part of a partial cross section of an MR element of a magnetic head.
1 is a lower shield and at least a reproduction track of the MR element.
Permalloy, which has a width larger than the magnetic flux detection width A
Vacuum deposition or plating of soft magnetic materials such as dust
Or made of soft magnetic material such as ferrite
Has been established. 2 is an insulating layer of SiO_Two And Al_Two O_Three Such
Oxide by vacuum deposition such as evaporation or sputtering
The film is formed. Reference numeral 3 denotes an MR element,
Fe-Ni alloys or Co-N
tens of nm or less for i-alloy to increase sensitivity to external magnetic field
It is formed of a particularly thin film below. These thin films are vacuum
True methods such as vapor deposition, sputtering, and ion beam sputtering
The film is formed by an empty film forming method. 4 indicates a current to the MR element 3
It is a lead layer for supplying and detecting the voltage change,
It is in contact with the MR element 3 outside the magnetic flux detection width A. Lee
Au, Al, C as good conductors having low resistance
u, W or a laminated film thereof is used.
Deposition method, sputtering method, ion beam sputtering method, CVD method
The film is formed by a vacuum film forming method such as. 5 is the upper seal
The magnetic flux detection width A of the MR element 3 on the insulating layer 2
Soft magnetic materials such as permalloy and sendust with the above width
Vacuum deposition method such as evaporation or sputtering or plating
It is formed by a method. 6 is the upper gap in the recording gap
SiO 5 on the upper surface of field 5_Two And Al _Two O_Three Steam oxides
Film formed by vacuum deposition such as deposition or sputtering.
You. 7 is a recording core, a permalloy above the recording gap 6,
Soft magnetic materials such as sendust are deposited or sputtered.
Films are formed by vacuum evaporation or plating, and
Formed by physical or chemical methods
ing. 8 is a protective layer made of SiO_Two And Al_Two O_Three Such as oxidation
An object is deposited by vacuum evaporation such as evaporation or sputtering.
Have been. 9 is a recording facing surface magnetic field, 10 is a coil, and B is
This is the recording core width for recording. C is the width of the MR element
You.

Using the thin film MR effect type magnetic head manufactured as described above, the off-track characteristic of the standardized output and the like were examined.

(Evaluation of Off-Track Characteristics) FIG. 3 is a schematic view of an MR effect element portion of a thin film MR head effect type magnetic head according to one embodiment of the present invention. 20 is a magnetoresistive film layer, 21 is a non-magnetic insulating layer, and 22 is a soft magnetic layer. The soft magnetic layer 22 is magnetized by an induced magnetic field due to a detection current flowing through the magnetoresistive film layer 20, and the MR effect layer 20 is bias-magnetized by this magnetization. The bias angle mainly depends on the thickness of the soft magnetic layer 22 and the saturation magnetization. The product (B sdM) of the product (B sdSAL), the thickness of the magnetoresistive film layer 20, and the saturation magnetization
R) (B sdSAL / B sdMR). Therefore, in this example, in order to evaluate off-track characteristics, a sample was manufactured under the configuration conditions shown in Table 1 and evaluated.

[0018]

[Table 1]

(B sdSAL / B in Table 1)
The variation in the (sdMR) ratio is mainly due to the film thickness distribution depending on the position of the magnetoresistive film or the soft magnetic film in the substrate used in the sample fabrication. Evaluation conditions were as follows. Ten samples were prepared, a thin film magnetic recording medium having Hc = 1800 [Oe] and a magnetic film Br · δ = 185 [Gauss · μm] was used, a peripheral speed v = 5.6 m / sec, and a recording frequency 1 .75 [MHz] and a head flying height of 0.08 [μm], the dependence of the normalized output on off-track was determined. The off-track characteristic was measured according to the schematic diagram shown in FIG. FIG. 4 is a schematic diagram showing a method of measuring off-track of a thin film MR effect type magnetic head. A recording facing surface magnetic field 9 for performing recording on a magnetic recording medium by the thin film MR effect type magnetic head is generated, and the recording state is as shown in FIG. The recording width on the magnetic recording medium is indicated by I. When reproduction is performed using the MR element 3 on the magnetic recording medium on which such recording is performed, when the position of the MR element 3 is moved from F to G and H in FIG. An output change standardized by the maximum output is obtained on the vertical axis, and off-track characteristics can be obtained. FIG. 5 shows the average of the measured values.

FIG. 5 shows a thin film MR according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating the dependence of a normalized output on off-track of an effect type magnetic head. Note that the vertical axis represents the normalized reproduction output standardized at the maximum output. Next, a microtrack profile was obtained using the same sample to confirm the effect of improving off-track characteristics. The measurement method of the microtrack profile was performed according to the schematic diagram shown in FIG. FIG. 6 is a schematic diagram showing a method of measuring a microtrack profile of a thin film MR effect type magnetic head according to one embodiment of the present invention. In the microtrack profile, when a recording track narrower than the magnetic flux detection width A indicated by I 'in FIG. 6 is used and the position of the MR element 3 is moved from F to G and H, the vertical axis indicates the maximum output. The horizontal axis indicates the off-track amount. By evaluating the microtrack profile, the reproduction sensitivity distribution in the track width direction of the magnetic flux detector can be measured.
In the evaluation of this embodiment, the micro track width (I ') is set to 0.
The measurement was performed at 8 μm. FIG. 7 shows the measurement results. FIG. 7 is a microtrack profile of the thin-film MR effect type magnetic head of this embodiment. (B in Table 1)
The variation in the (sdSAL / B sMR) ratio is mainly due to the film thickness distribution depending on the position in the substrate of the magnetoresistive film or the soft magnetic film in the substrate used for manufacturing the sample.

(Comparative Example) As a comparative example, a conventional thin film MR
10 samples of the effect type magnetic head were prepared, and under the same conditions, the dependence of the normalized output on the off-track and the microtrack profile were obtained under the same conditions as in the examples.
It was shown to. FIG. 8 is a diagram showing the dependence of the normalized output normalized with the maximum output on the off-track of the thin film MR effect type magnetic head of the comparative example, and FIG. 9 is the micro track of the thin film MR effect type magnetic head of the comparative example.・ It is a profile. The vertical axis in FIG. 8 represents a standardized output standardized at the maximum output as in FIG.

As apparent from FIGS. 5 and 8, in this embodiment, the left-right asymmetry of the off-track characteristic is improved, and the negative reproduction output observed on the off-track side is reduced. I understand. In addition, standardized output 50
When the positive and negative off-track widths in the% line are K and J, respectively, L = [(K−J) / (K + J)] × 10
Off-track characteristics left-right asymmetry L defined by 0 [%]
8 is 8.7% in the comparative example of FIG. 8, and in FIG. 5 of the example of the present invention, L = 4.2%, indicating that the asymmetry is remarkably improved. Further, the negative normalized output En generated on one side of the off-track characteristic is obtained by comparing the comparative example of FIG.
= 0.10, whereas in the embodiment of the present invention shown in FIG. 5, En = 0.02, which is significantly reduced.

Next, in the microtrack profile, as apparent from FIGS. 7 and 9, the embodiment reduces the left-right asymmetry of the microtrack profile and reduces the negative reproduction output generated on one side of the microtrack profile. It can be seen that there is a remarkable effect on reduction. The microtrack profile represents the reproduction sensitivity distribution in the track width direction of the magnetic flux detecting section, and it can be said that the uniformization of the positional distribution of the reproduction sensitivity in the present invention has produced an effect of improving off-track characteristics.

Next, the relationship between the bias angle of the MR effect layer and the microtrack profile will be described.
Was considered using the magnetization vector during operation. FIG. 10, FIG.
1 is an operating magnetization vector diagram of the MR element portion of the thin film MR effect magnetic head of the comparative example, and FIG. 12 is an operating magnetization vector diagram of the MR element portion of the thin film MR effect magnetic head according to one embodiment of the present invention. It is. In these figures, M0 represents the magnetization vector of the magnetoresistive effect film in a biased state at the position of point P of the magnetoresistive effect film 1-1,
ext represents a recording signal magnetic field vector generated at the P position by a magnetized portion recorded at the position Q or Q 'on the magnetic medium. M0 is set to M0 by the recording signal magnetic field Hext.
Causes a rotation of the magnetization from to the vector indicated by M1.
Here, FIGS. 10 and 11 show that the magnetoresistive film layer 20 has four layers.
The case where bias is applied at 5 degrees (∠M0 = 45 °) is shown, which is a case of a comparative example with a conventional configuration. FIG. 12 shows a case where the magnetoresistive film layer 20 is biased at 30 degrees (∠M0 = 30 °), which is an embodiment of the present invention. As shown in FIG. 10, when the medium magnetization portion Q 'exists within the reproduction track width, the recording signal magnetic field Hext becomes {M
However, when the medium magnetization portion moves to a position outside the reproduction track width Q as shown in FIG. 11, the recording signal magnetic field Hext has the effect of decreasing ΔM0. An increase in ∠M0 means a decrease in the resistance of the magnetoresistive film layer 20, and a decrease in ∠M0 means an increase in the resistance of the magnetoresistive film layer 20. In other words, it can be seen that the polarity of the reproduction output is reversed when the position of the medium magnetization portion is Q 'and Q. However, when ΔM0 = 30 ° as shown in FIG. 12, even at the same Q position as in FIG. 11, the recording signal magnetic field Hext has the effect of increasing ΔM0, so that the polarity of the reproduction output does not reverse. This concept can explain that a negative reproduction output is generated only on the side of the off-track characteristic, and that the bias angle of the magnetoresistive film layer 20 strongly affects the off-track characteristic and reduces the bias angle. This can also explain the reason why the left-right asymmetry of the off-track characteristic can be reduced.

As described above, the off-track characteristic can be improved by reducing the bias angle of the MR effect layer. However, for example, as disclosed in Japanese Patent Application Laid-Open No. 62-184616, the bias angle can be reduced. Is known to reduce the read sensitivity and degrade the linear response of recording magnetic field detection.

The optimum bias angle for reproduction sensitivity and linear response is 45 degrees. As the bias angle deviates from 45 degrees, the reproduction sensitivity and linear response deteriorate as well.
As a result, it is also known that the reproduction output decreases and the amplitude asymmetry of the reproduction waveform increases.

Therefore, an examination was first conducted to evaluate the linear response. (Evaluation of linear responsiveness) The linear responsiveness is evaluated based on the relationship between amplitude vertical asymmetry and the second harmonic distortion defined by the ratio (in decibel notation) of the second harmonic component to the fundamental frequency component of the reproduced signal. Was done. Amplitude vertical asymmetry (A Asy
m) is A Asym = (Ep−En) / (Ep + E), where Ep is the positive output of the solitary wave reproduction output in the magnetization region of the soft magnetic film by the detection current, and En is the negative output.
n) × 100 [%]. FIG. 13 is a diagram showing the dependence of the second harmonic distortion factor on the amplitude vertical asymmetry of the thin film MR effect type magnetic head according to one embodiment of the present invention. The evaluation is based on the product of the thickness of the soft magnetic layer and the saturation magnetization (B sd
SAL) and the ratio (BsdSAL / BsdM) of the product (BsdMR) of the film thickness of the magnetoresistive film layer 20 and the saturation magnetization (BsdMR).
R) was changed over a wide range, and the amplitude vertical asymmetry was intentionally varied, except that the evaluation was performed under the same conditions as those for the evaluation of the off-track characteristics. In general, the second harmonic distortion factor is 30 dB or less in a practical range, and the results in FIG. 13 show that the amplitude vertical asymmetry is in a practical range in a range of -10% to 10%. This result simply shows the amplitude asymmetry, that is, the relationship between the reproduced waveform shape and the second harmonic distortion, and the relationship between the bias angle of the magnetoresistive film and the second harmonic distortion is clearly unique. Can not decide. This is because the linear response of the recording magnetic field detection obviously depends on the allowable input magnetic field width of the magnetoresistive element and the recording magnetic field intensity. For example, when the residual magnetic flux density of the magnetic recording layer of the magnetic recording medium to be used is Br, and when the film thickness of the magnetic recording layer is δ, Br · δ [Gauss · μm] is reduced, the amplitude vertical asymmetry is reduced. It is possible to reduce it. Therefore, it is understood that the range of the amplitude vertical asymmetry of −10% or more and 10% or less shown in FIG. 13 needs to be practically achieved regardless of the bias angle of the magnetoresistive film.

(Evaluation of Reproduction Sensitivity) Next, in order to evaluate the deterioration of the reproduction sensitivity, an evaluation was made in relation to the amplitude vertical asymmetry and the reproduction output. The evaluation samples were performed using the thin film magnetoresistive head of the example manufactured this time and a conventional thin film magnetoresistive head as a comparative example. FIG. 14 shows the result.

FIG. 14 also shows the negative normalized outputs En and En 'shown in FIGS. FIG. 14 is a diagram showing the dependence of the reproduction output and the negative normalized reproduction output on the amplitude vertical asymmetry of the thin film MR effect type magnetic head according to one embodiment of the present invention. Generally, the playback output is 0.4 mV
If it is more than pp, it is practically possible.
From the results, it has been clarified that there is no practical problem in linear response and reproduction sensitivity even under the constitution conditions of the present invention. Further, as shown in FIG. 14, it was found that the embodiment of the present invention has a remarkable effect of improving the negative normalized reproduction output En over the comparative example having the conventional configuration.

A summary of the comparison results between the above-described embodiment of the present invention and a comparative example is shown in (Table 2).

[0031]

[Table 2]

As is clear from Table 2, according to the present embodiment, there is no practical problem in the reproduction output and the second harmonic distortion, and the off-track characteristic left-right asymmetry with respect to the comparative example. It has become clear that it is possible to significantly improve the negative normalized reproduction output En, and as a result, it is possible to obtain a magnetoresistive head having an extremely high track density.

(Study on Magnetic Recording Medium) Next, using the thin film MR effect type magnetic head of the embodiment, the residual magnetic flux density (Br) and the film thickness (δ) of the magnetic recording layer are variously changed to optimize the magnetic recording medium. Was studied. As a result, when Br · δ exceeded 185 [Gauss · μm], the tendency that the amplitude asymmetry deteriorated was recognized. Also Br · δ
Is smaller than 120 [Gauss · μm], there is a tendency that the reproduction output decreases.

From the above results, Br · δ [Gauss · μm] on which the thin film MR effect type magnetic head of the present invention is mounted is 1
It was found that 20 ≦ Br · δ ≦ 185 was preferable.

[0035]

As described above, according to the present invention, the left-right asymmetry of off-track characteristics in a reproduced signal can be improved, and a negative reproduced signal generated at the time of off-track can be reduced. As a result, the recording density can be significantly increased. An excellent magnetoresistive head that can be improved can be realized, and has a high track recording density.

[Brief description of the drawings]

FIG. 1 is an enlarged view of a main part of an MR element of a thin film MR effect type magnetic head according to an embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a main part of a partial cross section of an MR element of a thin film MR effect type magnetic head according to an embodiment of the present invention.

FIG. 3 is a schematic view of an MR effect element portion of a thin film MR effect type magnetic head according to one embodiment of the present invention.

FIG. 4 is a schematic view showing a method of measuring off-track of a thin-film MR effect type magnetic head according to one embodiment of the present invention.

FIG. 5 is a diagram showing the dependence of the normalized output on the off-track of the thin film MR effect type magnetic head in one embodiment of the present invention.

FIG. 6 is a schematic view showing a method of measuring a microtrack profile of a thin-film MR effect type magnetic head according to one embodiment of the present invention.

FIG. 7 is a diagram showing a microtrack profile of a thin film MR effect type magnetic head according to one embodiment of the present invention.

FIG. 8 is a diagram showing the dependence of a normalized output normalized with a maximum output on off-track of a thin film MR effect type magnetic head of a comparative example.

FIG. 9 is a view showing a microtrack profile of a thin film MR effect type magnetic head of a comparative example.

FIG. 10 is a magnetization vector diagram during operation of the MR element portion of the thin film MR effect type magnetic head of the comparative example.

FIG. 11 is a magnetization vector diagram during operation of the MR element portion of the thin film MR effect type magnetic head of the comparative example.

FIG. 12 shows the MR of the thin-film MR effect type magnetic head of this embodiment.
Operation part magnetization vector diagram

FIG. 13 is a diagram showing the dependence of the second harmonic distortion on the amplitude vertical asymmetry of the thin film MR effect type magnetic head according to one embodiment of the present invention.

FIG. 14 is a diagram showing the dependence of the reproduction output and the negative normalized reproduction output on the amplitude vertical asymmetry of the thin film MR effect type magnetic head in one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower shield 2 Insulating layer 3 MR element 4 Lead layer 5 Upper shield 6 Recording gap 7 Recording core 8 Protective layer 9 Recording opposing surface magnetic field 10 Coil 20 Magnetoresistive film layer 21 Nonmagnetic insulating layer 22 Soft magnetic layer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 5/39

Claims (1)

(57) [Claims] A soft magnetic layer laminated on one surface of the magnetoresistive layer or via a nonmagnetic insulating layer, wherein the soft magnetic layer is magnetized by a current flowing through the magnetoresistive layer, and the magnetization causes the soft magnetic layer to be magnetized. A thin-film magneto-resistance effect type magnetic head for applying a bias magnetic field to a magneto-resistance effect layer, wherein the product of the thickness of the soft magnetic layer and the saturation magnetization is 30 times the product of the thickness of the magneto-resistance effect layer and the saturation magnetization. % To 50%.