JPH0438614A - Magneto-resistance effect element and its applied magnetic head and recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dedicated magneto-sensitive element for reading information recorded on a magnetic recording medium, and more specifically, to a magneto-sensitive element for reading information recorded on a magnetic recording medium. The present invention relates to a highly sensitive magnetoresistive magnetic sensing element, a magnetic head using the same, and a magnetic recording/reproducing device.

[Conventional technology]

For example, a conventional magnetoresistive element using a soft magnetic film as a bias magnetic field applying means is disclosed in Japanese Patent Application Laid-Open No. 50-65213.
As described in the publication, the structure is such that two conductor parts are provided at both ends of the magnetoresistive film, and the output of this type of magnetoresistive element is parabolic in response to an external magnetic field. This shows the output. On the other hand, JP-A-61-
No. 199684 proposes a magnetoresistive element for the purpose of expanding the dynamic range and reducing noise. This is a bias-type magnetoresistive element using a soft magnetic material in which the output of the magnetoresistive element is differentiated. This magnetoresistive element has a common conductor part provided in the center of the magnetoresistive film in order to make a differential signal, and a common conductor part provided at both ends of the magnetoresistive film. This is a magnetoresistive element having a configuration in which a total of three conductor parts are provided.

[Problem to be solved by the invention]

With the demand for increased magnetic recording density, it is also necessary to reduce the recording track width. The magnetoresistive element described in Japanese Patent Application Laid-Open No. 50-65213, which is the prior art mentioned above, has two conductor parts, so it is advantageous for magnetic recording media with narrow tracks. The drawback was that the dynamic range was narrow because the output was parabolic.

On the other hand, the conventional differential type magnetoresistive element described in 41 of JP-A-61-199684 is advantageous in that it has a wide dynamic range, but as the tracks of magnetic recording media become narrower, , the corresponding 3
In order to manufacture a magnetoresistive element having a conductor part, it is necessary to reduce the width of the conductor part connected to the center of the magnetoresistive film, and this is necessary from the viewpoint of patterning accuracy, electromigration, etc. The problem was that it was extremely difficult. Further, a problem common to both is that when the track is made narrower, the current density distribution in the magnetoresistive film affects the reproduction output of the element.

An object of the present invention is to solve the above-mentioned problems in the prior art, and to configure a magnetoresistive element having three conductor parts corresponding to narrower tracks of high-density magnetic recording media, and An object of the present invention is to provide a magnetoresistive element that can obtain a type of element output and has a wide dynamic range, a magnetic head using the same, and a magnetic recording/reproducing device.

[Means for Solving the Problems] In order to achieve the above-mentioned object of the present invention, the direction of the signal detection current flowing through the conductor connected to the magnetoresistive element is set so that the direction of the signal detection current flowing through the conductor connected to the magnetoresistive element is aligned with the track of the magnetic recording medium at least on the magnetoresistive film It is configured to be approximately parallel to the width direction. Specifically, the common conductor section provided in the center of the magnetoresistive film provided to differentiate the magnetoresistive element is arranged substantially parallel to the track width direction at least on the magnetoresistive film. The magnetoresistive element of the present invention can be realized by forming the magnetoresistive element as follows.

[For production]

By placing the conductor in the center of the magnetoresistive film, which is provided to make the magnetoresistive element differential, in parallel to the magnetoresistive film, detection is possible near the connection between the conductor and the magnetoresistive film. The current density distribution becomes uniform over the entire surface of the magnetoresistive film. As a result, when a magnetic field signal from the medium is applied to the magnetoresistive film, the direction of magnetization changes over the entire surface of the film, so even if the track is made narrower, the reduction in reproduction output due to the current density distribution of the detection current is suppressed. can do.

Further, the conductor portion formed on the magnetoresistive film generates bias magnetic fields in opposite directions on the right side and left side of the through hole, respectively. Due to this bias magnetic field in the opposite direction, the voltage change of the magnetoresistive film on the left side and the magnetoresistive film on the right side of the center changes to the signal magnetic field from the magnetic recording medium with reference to the bias point when the magnetic field is 0 (zero). It acts to increase or decrease. As a result, the voltage change of the entire magnetoresistive film in which both are combined exhibits a voltage change similar to the voltage change obtained when differentialization is performed.

〔Example〕

An embodiment of the present invention will be described below in more detail based on the drawings.

(Example 1) FIG. 1 is a perspective view showing an outline of the configuration of a magnetoresistive element exemplified in this example, and FIG. 2(a) is an example of the configuration of a magnetoresistive element in this example. 2(b) is a sectional view taken along the line AA in FIG. 2(,).

In this embodiment, a magnetic shield 2 made of a soft magnetic material film such as a Ni-Fe alloy is placed on a substrate 1 with a thickness of 0.5 to 3
The layers were laminated to a thickness of μm by means such as vacuum evaporation or sputtering, and patterned into a predetermined shape by photolithography. On top of that, a layer of Sin or AQ203 to form the insulating layer 3 was laminated to a thickness of 0.05 to 0.5 μm using a sputtering method.

A Ni--Fe alloy, etc., which will become the magnetoresistive film 4, was laminated on the insulating layer 3 using a vacuum evaporation method, a sputtering method, or the like, and then patterned into a predetermined shape using a photolithography method. Note that the magnetoresistive film 3 is made of Ni-Fe.
In addition to alloys, there is no problem in using other alloy-based materials that have a magnetoresistive effect, such as Ni-Go alloys. Subsequently, a conductor section 5 for passing a detection current through the end of the magnetoresistive film 4 was fabricated by laminating a good conductor such as Cu and patterning it by photolithography. Here, the interval between the two conductor portions 5, ie, the track width, was set to 5 μm. Furthermore, as the material for the conductor portion 5, other materials such as Au and Ag can also be suitably used in addition to Cu.

Next, Sin, Afl, 03, which will become the insulating layer 6, is laminated to a thickness of 0.05 to 1.0 μm by sputtering or the like.
After opening a through hole 7 using a photolithography method, a conductor section 8, which also serves as a bias application means, through which a detection current is passed from the center of the magnetoresistive film 4, is laminated using a good conductor such as Cu. It was produced by patterning into a predetermined shape. Here, so that the output waveforms obtained from the magnetoresistive film 4 on the left side of the through hole 7 and the magnetoresistive film 4 on the right side are symmetrical,
The through hole 7 must be located at the center of the magnetoresistive film 4. Further, the conductor portion 8 is provided in parallel above or below the magnetoresistive film 4 so that it can also be used as a bias applying means. Here, through hole 7
The width was 0.8 μm. The material of the conductor part 8 is Cu.
In addition, Au, Ag, etc. can also be suitably used.

Next, the insulating layer 9 is made of Sin, Af1203, etc.
．． 05 to 1.0 μm lamination. On top of that, a soft magnetic material such as Ni-Fe alloy, which will become the magnetic shield 10, is applied to the
．． The layers were stacked to a thickness of 0 μm and patterned into a predetermined shape using photolithography.

Furthermore, a pad portion 1 for introducing a detection current is placed on the conductor portion 5.8.
2 using a good conductor such as Cu, and finally a protective layer 11 made of SiO□ or Af120. 1
By laminating layers of 0 to 50 μm, the magnetoresistive element 13
was created.

Next, the operation of the magnetoresistive element 13 manufactured by the above method will be explained. First, pad portions 12a and 12b,
Detection currents 11 and 12 are passed between conductor portions 8 and 5 between 12c and 12d, respectively.

At this time, the sizes of i□ and 12 are made equal. The bias magnetic fields generated by the detection currents 11 and 12 in the conductor section 8 are in opposite directions on the left and right sides of the through hole 7. As a result, the direction of magnetization in both magnetoresistive films 4 is M
As shown by 1 and M2, the directions are opposite to the currents 11 and 12 and form a certain angle θ. When a magnetic field signal 15 from the magnetic recording medium 14 is applied to this state, the voltage change measured through the magnetoresistive film 4 on the left side of the through hole 7 is +ΔV with respect to the signal magnetic field as shown in the curve 16 shown in FIG. causes a change in On the other hand, the voltage change measured through the magnetoresistive film 4 on the right side is -ΔV, which is completely 180° symmetrical with respect to the signal magnetic field, as shown in the curve 17 shown in the figure.
This indicates a change in

In the end, the voltage change ΔV across the entire magnetoresistive film, which is read from the pad portions 12a to 12d, is on the positive (plus) side and the negative (minus) side of the signal magnetic field H, as shown by the curve 18 shown in FIG. The positive and negative signal magnetic fields H written on the medium can be detected as an output waveform corresponding to the waveform of the curve 18.

Magnetoresistive element 13 produced in this example above
The output waveform obtained by the curve 18 in FIG. 3 is almost equivalent to the waveform obtained by a conventional magnetoresistive element in which the magnetoresistive film 4 is made differential. That is, there is an effect that the dynamic range for the signal magnetic field H can be expanded and at the same time noise can be reduced. Furthermore, since the direction of the detection current i□, 12 flowing through the conductor portion 8 is parallel to the track width direction on the magnetoresistive film 4, the detection current flows uniformly over the entire surface of the magnetoresistive film 4. This has the effect of preventing a reduction in reproduction output due to current density distribution caused by narrowing the track.

Here, there is a close relationship between the width of the through hole 7 and the width of the dynamic range, and if the width of the through hole 7 is doubled or tripled, the dynamic range will be reduced to 1/2.1/3. Two terminal heads and three with the same track width
If the dynamic range of the terminal heads were to be the same, there would be no point in forming a differential head. Therefore, it is necessary to make the width of the through hole 7 as narrow as possible. With the current photolithography technology, it is possible to form a pattern of 0.5 μm@ by using excimer laser light, and the width of the through hole 7 can also be set to 0.5 μm. Therefore, in order to narrow the track and make the width of the through hole 7 from 1/2 of the track width to a minimum of 0.5 μm, the ratio of the width of the through hole 7 to the track width should be 1/2 to 0.5 μm.
A range of 1/40 is desirable.

Although this embodiment shows a case in which the conductor section 8 is provided in parallel to the upper part of the magnetoresistive film 4 as a bias applying means, the present invention may also be applied in combination with a shunt film, a current line, a permanent magnet, etc. The effect remains unchanged.

In addition, in this example, an example is given in which a soft magnetic thin film is used for the magnetic shield 2.10, but the same effect as above can be obtained even if a bulk soft magnetic material is used instead. Needless to say.

(Example 2) FIG. 4 is a perspective view schematically showing the configuration of a magnetoresistive element exemplified in this example. In this example, in the conductor portion 5.8 of the magnetoresistive element 13 shown in Example 1, the width of the portion connected to the magnetoresistive film 4 or its vicinity is narrower than that of the rear part. It is. According to this embodiment, the detection current 11 is applied to the conductor portion 8.5.
．． When a current of 12 is applied, the current density becomes high in the narrow conductor portion, and a magnetic field of H is generated on the left side of the magnetoresistive film 4, and a magnetic field of H2 is generated on the right side of the magnetoresistive film 4. This provides the same effect as when permanent magnets are provided at both ends of the magnetoresistive film 4, and prevents fluctuations in the magnetic domain structure of the magnetoresistive film when a signal magnetic field from a magnetic recording medium enters. This makes it possible to eliminate waveform distortion such as Barkhausen noise that occurs in the reproduced output waveform.

As a result of examining the characteristics of the obtained magnetoresistive element, it was found that almost the same performance as the magnetoresistive element 13 of Example 1 was obtained, and the same results were obtained in terms of operation and effect. .

Although this embodiment also shows the case where a conductive film is provided in parallel above the magnetoresistive film 4 as a bias applying means, the present invention can also be achieved by using a shunt film, a current line, a permanent magnet, etc. The effect remains the same. Further, although an example has been given in which a soft magnetic material film is used for magnetic shielding, it goes without saying that the same effect as described above can be obtained even if a bulk soft magnetic material is used instead.

(Example 3) FIG. 5(,) is a perspective view schematically showing the configuration of the magnetoresistive element illustrated in this example, and FIG. FIG. 2 is a cross-sectional view showing a substrate 1 and an insulating layer 3.
．． 9. Consists of a magnetic shield 2.10 and a protective layer 11. In this embodiment, the shape of the magnetoresistive film 4 of the magnetoresistive element 13 shown in the first embodiment is T-shaped. According to this embodiment, the tip of the magnetoresistive film 4 protrudes, as shown in FIG. 5(b).
The gap length 19 can be shortened when the magnetic shield 2.10 is formed as shown in FIG. As a result of examining the characteristics of the obtained magnetoresistive element, it was found that almost the same performance as the magnetoresistive element 13 of Example 1 was obtained, and the same results were obtained in terms of operation and effect. .

In this embodiment, a conductive film is installed parallel to the upper part of the magnetoresistive film as a bias applying means, but the present invention may also be applied using a shunt film, a current line, a permanent magnet, etc. The effect remains unchanged. Further, although an example has been given in which a soft magnetic material film is used for magnetic shielding, it goes without saying that the same effect as described above can be obtained even if a bulk soft magnetic material is used instead.

(Example 4) FIG. 6 is a perspective view schematically showing the configuration of a magnetoresistive element exemplified in this example. In this example, the conductor portion 8 of the magnetoresistive element 13 shown in Example 1 above is used.
is provided parallel to the conductor portion 5, and the width of the conductor portion 8 is wider than the width 20 of the through hole.

In this embodiment, first, a detection current i is caused to flow from the conductor section 8 toward the conductor section 5. Since the width of the conductor portion 8 is wider than the width 20 of the through hole, the detection current i flows from the width direction of the conductor portion 8 toward the center of the through hole so as to be exactly parallel to the magnetoresistive film 4 . Thereby, the conductor part 8 can also serve as a bias applying means, similar to the case where the conductor part 8 is provided in parallel with the magnetoresistive film 4 as in the first embodiment.

As a result of examining the characteristics of the obtained magnetoresistive element, it was found that almost the same performance as the magnetoresistive element 13 of Example 1 was obtained, and the same results were obtained in terms of operation and effect. .

In this embodiment, even if a shunt film, a current line, a permanent magnet, or the like is used above the magnetoresistive film, the effects of the present invention do not change. Further, although an example has been given in which a soft magnetic material film is used for magnetic shielding, it goes without saying that the same effect as described above can be obtained even if a bulk soft magnetic material is used instead.

〔Effect of the invention〕

As explained in detail above, the magnetoresistive element of the present invention has one conductor section on the central film surface of the magnetoresistive film and two conductor sections at both ends, so that the magnetoresistive element of the present invention is different from the conventional differential type magnetoresistive element. Since the same effect as an effect element can be obtained, it is possible to realize high-density recording and reproduction in response to narrower tracks, and at the same time, it is possible to achieve the effect of expanding the dynamic range and reducing noise even with narrower tracks.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing the structure of the magnetoresistive element illustrated in Example 1 of the present invention, and FIG.
2(b) is a sectional view taken along the line A-A in FIG. 2(a); FIG. FIG. 4 is a perspective view schematically showing the structure of the magnetoresistive element illustrated in Example 2 of the present invention, and FIG. 5(a) is a perspective view schematically showing the structure of the magnetoresistive element illustrated in Example 3 of the present invention. FIG. 5(b) is a sectional view taken along line BB in FIG. 5(a), and FIG. 6 is a perspective view schematically showing the structure of the magnetoresistive element illustrated in Example 4 of the present invention. be. 1... Substrate 2.10... Magnetic shield 3.6.9... Insulating layer 4... Magnetoresistive film 5.8... Conductor part 7... Through hole 11
...Protective layer 12...Pad portion 13...
Magnetoresistive element 4...Magnetic recording medium 15...Magnetic field signal 6...
Voltage change that changed to the positive side 7... Voltage change that changed to the negative side

Claims (1)

[Scope of Claims] 1. A magnetoresistive film for detecting a leakage magnetic flux signal from a magnetic recording medium, means for applying a bias to the magnetoresistive film, and simultaneously applying a current to the magnetoresistive film, The magnetoresistive element comprises conductor parts for reading the voltage, which are provided at three locations at both ends and the center of the magnetoresistive film, and a pair of magnetic shield members that magnetically shield the magnetoresistive film. A magnetoresistive element characterized in that, at least on the magnetoresistive film, an electrode portion formed by the central conductor portion is arranged substantially parallel to the track width direction of the magnetic recording medium. 2. In claim 1, the direction of the signal detection current flowing through the conductor connected to the center of the magnetoresistive film is substantially parallel to the track width direction of the magnetic recording medium, at least on the magnetoresistive film. A magnetoresistive effect element characterized by being configured so that: 3. Claim 1 or 2 is characterized in that the ratio of the width of the connection portion between the conductor portion provided in the center and the magnetoresistive film to the track width is 1/2 to 1/40. A magnetoresistance effect element. 4. In the two conductor portions connected to both ends of the magnetoresistive film of the magnetoresistive element according to claim 1, 2, or 3, the portion connected to the magnetoresistive film or its A magnetoresistive element characterized in that the width of a nearby conductor part is smaller than the width of the rear part of the conductor part. 5. A magnetoresistive element according to any one of claims 1 to 4, characterized in that the magnetoresistive film has a T-shape. 6. The magnetoresistive element according to any one of claims 1 to 5, characterized in that a thin film or bulk magnetic shielding member is provided on both sides of the magnetoresistive film. element. 7. In the magnetoresistive element according to any one of claims 1 to 6, the bias applying means is a combination of at least one selected from a shunt film, a current line, and a permanent magnet. 1. A magnetoresistive effect element configured using 8. A magnetoresistive element according to any one of claims 1 to 7, characterized in that a conductor portion is provided above or below the magnetoresistive film. 9. A leakage magnetic flux signal from a narrow track high-density magnetic recording medium is detected with high sensitivity using the magnetoresistive element according to any one of claims 1 to 8. A magnetic head comprising a magnetic head for reading recorded information. 10. A means for reading information recorded on the magnetic recording medium by detecting leakage magnetic flux signals from the high-density magnetic recording medium using the magnetic head according to claim 9 is provided. A magnetic recording/reproducing device characterized by: