JP2002050007A - Magnetic head, its manufacturing method and magnetic reproducing device using the magnetic head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic head capable of making detection with sensitivity higher than that of the MI head of a conventional constitution even when a recording density becomes high, and its manufacturing method. SOLUTION: This magnetic head is provided with a first soft magnetic material film formed on a substrate made of a non-magnetic material, a conductive metal film formed to penetrate the first soft magnetic material film, and a return path yoke composed of a second soft magnetic material film formed on the substrate such that an end part is brought into contact with the first soft magnetic material film, and a center part faces the first soft magnetic material film through the non-magnetic material. At a frequency higher than a reproducing signal a frequency, the second soft magnetic material film has magnetic permeability lower than that of the first soft magnetic material film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head utilizing a magnetic impedance effect in which the impedance of a detection conductor is changed by an applied magnetic field, and a magnetic reproducing apparatus using the magnetic head.

[0002]

2. Description of the Related Art FIG.
FIG. 9 is a perspective view of a conventional reproducing magnetic head (hereinafter, referred to as “MI head”) 61 using a magneto-impedance effect (MI effect) reported in 95-80.

In FIG. 11A, an MI head 61 is provided.
Is a magnetic impedance effect detecting section (hereinafter, referred to as a “magnetic impedance effect detecting section”) in which a detection conductor line 42 made of a conductive metal thin film is sandwiched between a pair of soft magnetic cores 46 and 47 having a width 43 substantially equal to the track width of a magnetic recording medium 53. A magnetic detection unit is called.) A pair of soft magnetic cores 46 and 47
As shown in FIG. 11B, which is a partially enlarged view, is formed of a laminated film in which permalloy films 44 and SiO ₂ films 45 are alternately laminated.

[0004] A magnetic recording medium 53 is
When reproducing the magnetized signal 54 recorded in the RF signal, a high frequency carrier signal in the UHF band is applied to the detection conductor line 42 from the high frequency
Flow 0. Then, a voltage change generated between the terminals 51 and 52 connected to both ends of the detection conductor wire 42 is detected by the magnetic impedance effect. The directions of the axes of easy magnetization of the soft magnetic cores 46 and 47 are determined in advance by the magnetic recording medium 5.
3 is oriented in the width direction of the recording track.

When the magnetization signal 54 does not exist in the magnetic recording medium 53, the voltage between the terminals 51 and 52 is equal to the product of the high-frequency current 50 and the impedance between the terminals 51 and 52 of the detection conductor wire 42. A high-frequency carrier signal voltage is generated.

When the magnetization signal 54 exists in the magnetic recording medium 53, the directions of the axes of easy magnetization of the soft magnetic cores 46 and 47 are deviated from the directions orientated in advance by the magnetization signal 54, respectively. As a result, the impedance between the terminals 51 and 52 of the detection conductor wire 42 decreases due to the magnetic impedance effect.

The high-frequency carrier signal is AM-modulated and detected by the magnetization signal 54 of the magnetic recording medium 53 due to the change in the impedance of the detection conductor line 42. By subjecting this signal to AM detection, the magnetization signal 54 of the magnetic recording medium 53 can be read.

The detection sensitivity of the magnetization signal 54 of the magnetic recording medium 53 by the magneto-impedance effect is much higher than the detection sensitivity by the magneto-resistance effect. An MI head utilizing the magneto-impedance effect may provide about ten times as much output as a known giant MR head using a magnetic bubble which is currently under development.

FIG. 12 is a characteristic curve showing a change in high-frequency carrier signal level with respect to a magnetic field applied to the MI head 61. In FIG. 12, the characteristic curve 56 is
With the frequency of the high-frequency carrier signal being 1 GHz, the above-described MI head 61 is placed at the center of the Helmholtz coil,
It is obtained by changing the intensity of the applied DC magnetic field.

According to the characteristic curve 56, the high-frequency carrier signal level gradually changes when the applied magnetic field intensity is near zero. In order to modulate a high-frequency carrier signal with a large degree of modulation with respect to a change in magnetic field strength and to obtain a high-frequency carrier signal with little distortion, a DC bias magnetic field 55 for biasing to use a linear portion of the characteristic curve 56 is used. It is desirable to give. In the conventional MI head, in order to generate a DC bias magnetic field 55, a DC current is superimposed on a high-frequency carrier signal current by a DC power supply 58. In this way, a DC magnetic field is generated by flowing a DC current through the detection conductor wire 42 to be a bias magnetic field.

The rate of change of the impedance of the detection conductor due to the magnetic impedance effect is proportional to the product of the frequency of the high-frequency carrier signal applied to the detection conductor and the rate of change of the magnetic permeability of the soft magnetic core. In order to increase the rate of change of the impedance of the detection conductor and increase the detection sensitivity, a conventional MI
In the head, the permalloy film 44 having a large change in magnetic permeability is used as the material of the soft magnetic cores 46 and 47 as described above, and the permalloy film 44 and SiO ₂ as an insulator are used to prevent generation of eddy current due to high frequency. A laminated film in which the films 45 are alternately laminated is used. Further, the frequency of the high-frequency carrier signal is a high frequency of several hundred MHz or more.

[0012]

However, as the magnetic recording density increases, the track width tends to be narrower, and as the track width becomes narrower, the strength of the magnetization signal 54 also tends to decrease. is there. For this reason, in the MI head having the conventional configuration as described above, the detection sensitivity may be insufficient, and it is difficult to form an MI head having high sensitivity.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a magnetic head capable of detecting with higher sensitivity than a conventional MI head even when the recording density is increased. It is intended to provide a manufacturing method.

[0014]

To achieve the above object, a magnetic head according to the present invention comprises: a first soft magnetic film formed on a substrate made of a non-magnetic material; A conductive metal film formed so as to penetrate the body film, and an end portion on the substrate in contact with the first soft magnetic film, and a center portion formed on the first soft magnetic film.
And a return path yoke composed of a second soft magnetic film formed so as to face the soft magnetic film of FIG. 1 with a non-magnetic material interposed therebetween. At a frequency higher than the frequency, the magnetic permeability is lower than the magnetic permeability of the first soft magnetic film.

With this configuration, when the magnetic permeability of the second soft magnetic film constituting the return path yoke is sufficiently low, the magnetic flux generated from the magnetization signal of the magnetic recording medium efficiently returns the return path yoke and the magnetic core. Through the magnetic path consisting of
The external magnetic field of the conductive metal film through which the high-frequency current flows passes through the magnetic core sandwiching the conductive metal film without leaking to the return path yoke, so that even high-density recording signals can be reproduced with high sensitivity. .

Next, in order to achieve the above object, a magnetic head according to the present invention comprises a first soft magnetic film formed on a substrate made of a magnetic material, and a first soft magnetic film penetrating through the first soft magnetic film. A first soft magnetic film is formed on the substrate such that the first soft magnetic film is opposed to the magnetic substrate via the non-magnetic material, so that the substrate can be returned to the return path. The magnetic permeability of the substrate is also lower than the magnetic permeability of the first soft magnetic film at a frequency higher than the reproduction signal frequency.

With this configuration, the soft magnetic film is formed in a so-called one-core shape, instead of the magnetic core formed on the substrate sandwiching the conductive metal film. Since the external magnetic field passes through the return yoke from the core, it is possible to efficiently detect the external magnetic field from a change in impedance even with only one of the cores.

In the magnetic head according to the present invention, it is preferable that a high-frequency carrier signal current is caused to flow through the conductive metal film, and a direct-current current is superimposed on the high-frequency signal current to apply a direct-current bias magnetic field. This is because it is possible to obtain a high-frequency carrier signal having a large degree of modulation with respect to a change in the magnetic field strength and having little distortion.

Further, the magnetic head according to the present invention has a second
Of the first soft magnetic film at the frequency of the high-frequency carrier signal is one third of the magnetic permeability of the first soft magnetic film.
The following is preferred. Further, it is preferable that the magnetic permeability of the substrate is one third or less of the magnetic permeability of the first soft magnetic film at the frequency of the high frequency carrier signal. This is because the external magnetic field can be more efficiently detected from the change in impedance. Further, when the magnetic permeability of the substrate is at least one third of the magnetic permeability of the first soft magnetic film at the frequency of the high frequency carrier, the magnetic flux due to the high frequency carrier signal flows not only to the magnetic core but also to the substrate, As a result, the efficiency in the magnetic core is reduced.

Further, in the magnetic head according to the present invention, it is preferable that a non-magnetic conductive metal film is formed on the non-magnetic portion and a DC current for a DC bias magnetic field is applied to the conductive metal film. This is to obtain a high-frequency carrier signal having a large degree of modulation with respect to a change in the magnetic field strength and a small distortion.

Next, in order to achieve the above object, a magnetic head according to the present invention comprises a first magnetic head formed on a non-magnetic substrate.
And a conductive metal film formed on a surface of the first soft magnetic film opposite to the substrate, and is in contact with the first soft magnetic film at an end on the substrate, A center portion thereof includes a return path yoke composed of a third soft magnetic film formed so as to face the first soft magnetic film via the conductive metal film and the non-magnetic material. I do.

According to this structure, the magnetic flux generated from the magnetization signal of the magnetic recording medium efficiently passes through the magnetic path formed by the return path yoke and the magnetic core, and the external magnetic field of the conductive metal film through which the high-frequency current flows flows to the return path yoke. Since the signal passes through the magnetic core sandwiching the conductive metal film without leaking, even a high-density recording signal can be reproduced with high sensitivity.

In the magnetic head according to the present invention, it is preferable to apply a DC bias magnetic field by flowing a high-frequency carrier signal current through the conductive metal film and superimposing a DC current on the high-frequency signal current. This is because it is possible to obtain a high-frequency carrier signal having a large degree of modulation with respect to a change in the magnetic field strength and having little distortion.

Next, in order to achieve the above object, a method of manufacturing a magnetic head according to the present invention comprises the steps of: forming a first soft magnetic film on a substrate and patterning a lower magnetic core;
Forming a conductive metal film and patterning a conductor line across the lower magnetic core; forming a first soft magnetic film and upper magnetic core sandwiching the conductor line with the lower magnetic core; Patterning and forming a non-magnetic film,
A step of patterning a gap on a magnetic core formed by an upper magnetic core and a lower magnetic core, a step of forming and patterning a nonmagnetic film, and a second soft magnetic layer having a magnetic permeability different from that of the magnetic core. A step of forming a film and forming a return path yoke so as to face the magnetic core via the nonmagnetic film pattern.

With this configuration, the first soft magnetic film has a conductive metal film formed so as to penetrate the magnetic core made of the first soft magnetic film and a return path yoke made of the second magnetic film. A magnetic head having a configuration in which the magnetic permeability of the second magnetic film is higher at a frequency higher than the reproduction signal frequency, the magnetic permeability of the second magnetic film is the highest at the reproduction signal frequency, and lower than the reproduction signal frequency of the first magnetic film. Can be.

Next, in order to achieve the above object, a method of manufacturing a magnetic head according to the present invention comprises the steps of: forming a non-magnetic film on a magnetic substrate and patterning the same; Patterning the gap so as to be in contact with the non-magnetic film pattern, forming a first soft magnetic film, and patterning the lower magnetic core so as to face the magnetic substrate via the non-magnetic film pattern Forming a conductive metal film and patterning a conductor line across the lower magnetic core; forming a first soft magnetic film and forming the upper portion so as to sandwich the conductor line with the lower magnetic core A step of patterning the magnetic core.

[0027] According to this structure, the conductive metal film formed so as to penetrate the magnetic core made of the first soft magnetic film and the return path yoke made of the second magnetic film are provided.
The magnetic permeability of the first soft magnetic film is higher at a frequency higher than the reproduction signal frequency, the magnetic permeability of the second magnetic film is the highest at the reproduction signal frequency, and the first magnetic film at a frequency higher than the reproduction signal frequency. A magnetic head having a lower configuration can be obtained.

Next, in order to achieve the above object, a method of manufacturing a magnetic head according to the present invention comprises the steps of: forming a soft magnetic film on a non-magnetic substrate and patterning a magnetic core; Forming a film and patterning the conductor lines across the magnetic core; forming a non-magnetic film and patterning the gap on the magnetic core; forming and patterning the non-magnetic film And a step of forming a third soft magnetic film and forming a return path yoke so as to face the magnetic core via the nonmagnetic film.

According to this structure, the conductive metal film is formed so as to cross the first soft magnetic material without penetrating the first soft magnetic material. It is possible to obtain a magnetic head having a return path yoke made of a soft magnetic film formed so as to be opposed to a body film via a non-magnetic material portion including the conductive metal film.

Next, in order to achieve the above object, a magnetic reproducing apparatus according to the present invention comprises a magnetic head as described above,
Recording medium holding means for reproducing a recorded signal;
Positioning means for positioning the magnetic head at a designated position on the recording medium.

With this configuration, the magnetic flux generated from the magnetization signal of the magnetic recording medium efficiently passes through the magnetic path including the return path yoke and the magnetic core, and the external magnetic field of the conductive metal film through which the high-frequency current flows leaks to the return path yoke. Without passing through the magnetic core sandwiching the conductive metal film,
It is possible to realize a magnetic reproducing apparatus capable of reproducing a high-density recording signal with high sensitivity.

[0032]

Embodiment 1 Hereinafter, a magnetic head according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a configuration sectional view of a magnetic head according to the first embodiment of the present invention.

In FIG. 1, a magnetic core 2 made of a first soft magnetic film is formed on a non-magnetic substrate 21. The magnetic sensor unit 4 is formed by forming a conductor wire 1 made of a conductive metal film that is a film of a good conductor such as copper so as to penetrate the magnetic core 2. One of the magnetic sensor units 4 is in contact with the return path yoke 6 of the second soft magnetic material film via the magnetic gap 8 and the other directly. The return path yoke 6 has a non-magnetic portion 5 at a portion corresponding to the conductor wire 1.
Is provided. The return path yoke 6 and the magnetic sensor section 4 form a ring-shaped magnetic path surrounding the non-magnetic body section 5 to form a ring head type magnetic head.

Here, the substrate 21 was made of a ceramic made of nickel, titanium and magnesium, the gap 8 and the non-magnetic material portion 5 were made of SiO ₂ , and the conductor wire 1 was made of copper. As the magnetic film, an alloy containing iron, tantalum, and nitrogen was used in which SiO ₂ was laminated as an interlayer insulating film, but the lamination method was changed as disclosed in Japanese Patent Application No. 11-740. Can also control the magnetic permeability. FIG. 2 shows the frequency characteristics of the effective magnetic permeability of the soft magnetic film used in the first embodiment. Here, the soft magnetic film B is used as the first soft magnetic film and the soft magnetic film A is used as the second soft magnetic film.

FIG. 3 is a right side view of the magnetic head according to the first embodiment of the present invention. In FIG. 3, the conductor wire 1
Are provided with electrodes 15 and 16 at both ends.
A constant-current high-frequency oscillator 11 and a DC power supply 20 for generating a bias magnetic field connected in parallel to a first pair of electrode terminals 13 and 14 connected to the electrodes 15 and 16 are connected via a resistor 12 to superimpose a DC current. High frequency current (for example, 1GH
z) is applied to the conductor wire 1. A high frequency amplifier 19 is connected to the second pair of electrode terminals 17 and 18. In this state, as shown in FIG. 1, when the magnetic head runs on the magnetic recording medium 10, the magnetization signal 9 of the magnetic recording medium 10
From the gap 8 flows into the magnetic head. Magnetic core 2 and return path yoke 6
Is the signal frequency from the medium (for example, 20 MHz)
In the magnetic core 2 using the soft magnetic film B,
0, 2 in the return path yoke 6 using the soft magnetic film A.
Since the magnetic flux is high enough to pass the magnetic flux, the magnetic flux passes through the magnetic core 2 sandwiching the conductor wire 1 and enters the return path yoke 6 to form a closed loop returning to the magnetization signal 9 of the magnetic recording medium 10.

At this time, as shown in FIG. 2, the magnetic permeability at a high frequency (for example, 1 GHz) shows a relatively high value of 1050 in the magnetic core 2 using the soft magnetic film B. In the return yoke path 6 made of the magnetic film A, 8
0, which is very low. Therefore,
The magnetic permeability of the magnetic core 2 mainly at a high frequency (1 GHz) changes. As a result, the impedance of the conductor line 1 changes according to the intensity of the magnetization signal 9 generated from the magnetic recording medium due to the MI effect, and the high-frequency current is AM-modulated. The magnetized signal 9 is detected by amplifying and detecting a signal based on the AM modulation current by the high frequency amplifier 19 connected to both ends of the electrodes 15 and 16. The magnetic permeability shown in FIG. 2 is a magnetic permeability measuring device (PHF-F1000B) of Naruse Chemical Instruments Co., Ltd.
H).

As a test magnetic recording medium, a CoCrPt-based magnetic material having an areal recording density of 3.1 gigabits per cm ² was used, and the distance between the head and the magnetic recording medium was 1 μm.
As m, a magnetization signal previously recorded using an inductive ring head was reproduced using the magnetic head according to the first embodiment of the present invention.

For the above magnetic head, the intensity H of the magnetization signal and the magnetic flux density B in the magnetic head caused by the magnetization signal
FIG. 4 shows the result of examining the relationship with. In FIG. 4, the horizontal axis represents the magnetic field strength H due to the magnetization signal, and the vertical axis represents the magnetic flux density B of the magnetic core 2. The curve in FIG.
It is called “HB curve”. )), The magnetic flux density B is also equal to the magnetic flux density B2 until the magnetic field strength H due to the magnetization signal is about H2.
However, if it exceeds that, the rate of increase of the magnetic flux density B decreases. A bias magnetic field is applied by the DC power supply 20 shown in FIG. 3 so that the magnetic flux density B becomes the magnetic flux density Bb. In this state, when the magnetic field generated by the magnetization signal changes between the intensity H1 and the intensity H2, the input voltage of the high-frequency amplifier 19 changes between the voltage V1 and the voltage V2 to become an AM modulation signal.

The reason why the input voltage changes between the voltage V1 and the voltage V2 is as follows. That is, as the magnetic flux density B changes, the axis of easy magnetization of the magnetic core 2 shifts from the direction in which the magnetic core 2 is oriented in advance. As a result, the magnetic permeability of the magnetic core 2 changes, the impedance of the conductive film 1 penetrating the magnetic core 2 changes, and the high-frequency voltage applied from the constant-current high-frequency oscillator 11 changes.

FIG. 5 is a sectional view showing a method of manufacturing the magnetic head according to the first embodiment.

FIG. 5A shows that a soft magnetic film B having a thickness of 0.5 μm is formed on a ceramic substrate 21 by sputtering, and the lower magnetic core 2 is formed by ion milling.
2 is patterned.

FIG. 5B is a diagram in which copper is formed as a metal conductor thin film to a thickness of 1 μm by sputtering, and the conductor wire 1 is patterned by ion milling.

FIG. 5C shows a soft magnetic film B having a thickness of 0.5 μm formed by sputtering, and the upper magnetic core 23 is patterned by ion milling. The conductor core 1 is patterned so as to sandwich the conductor wire 1 between the lower magnetic core 22 and the upper magnetic core 23 to form the magnetic core 2.

FIG. 5D shows a SiO ₂ film having a thickness of 0.5 μm formed as a gap material by sputtering, and the magnetic gap 8 is patterned by ion milling. Since the non-magnetic portion 5 following this also uses SiO ₂ , the pattern was extended to the portion covered by the non-magnetic portion 5. Thereby, the magnetic core 23 can be protected from over-etching during the patterning of the magnetic gap 8, and the gap can be formed continuously even in the uneven portion of the magnetic core.

FIG. 5E shows a SiO ₂ film having a thickness of 2 μm formed as a non-magnetic film by sputtering, and the non-magnetic portion 5 is patterned by ion milling.

FIG. 5F shows a soft magnetic film A having a thickness of 3 μm formed by sputtering and a return path yoke 6 patterned by ion milling.

Further, a gap depth of the head is determined by forming an alumina film of 5 μm as a protective film and wrapping the medium facing surface 7. The polished surface becomes the surface facing the magnetic recording medium 10.

FIG. 6 is a sectional view showing a structural example of a magnetic head according to one embodiment of the present invention. In FIG. 6, a magnetic path portion 3 made of a soft magnetic film is provided in a portion of the magnetic core 2 where the conductor wire 1 does not penetrate. As described above, by providing the magnetic path portion 3 when the thickness of the magnetic core 2 is small, the magnetic flux generated from the magnetization signal 9 of the magnetic recording medium 10 can be smoothly transferred to the magnetic core 2.
And a return path yoke 6.

FIG. 7A is a sectional view showing a structural example of a magnetic head according to another embodiment of the present invention. The return yoke path 6 is formed by using a substrate as a magnetic material (eg, ferrite). The step of forming the soft magnetic film forming the return yoke path can be omitted. The manufacturing order is different from the above-described manufacturing method. The non-magnetic part 5 and the gap 8 are formed on the substrate, and the lower magnetic core 22, the conductor wire 1, and the upper magnetic core 2
After forming the protective film, the magnetic head is manufactured by cutting, wrapping, and the like. As shown in FIG. 7B, a concave portion corresponding to the non-magnetic portion 5 is provided in advance on the substrate, a non-magnetic film (such as SiO ₂ ) is formed, and the surface is made uniform by wrapping. , Lower magnetic core 2
2, the conductor wire 1, and the upper magnetic core 23 in this order,
The magnetic core 2 can be formed relatively flat, and cutting of the magnetic surface can be prevented.

As described above, according to the first embodiment, in forming the magnetic core and the return path yoke in the ring-type high-frequency impedance head, the magnetic recording medium is formed by using soft magnetic films having different magnetic permeability. It is possible to reproduce a high-density recording signal recorded in a high sensitivity with high sensitivity.

Embodiment 2 Hereinafter, a magnetic head according to Embodiment 2 of the present invention will be described with reference to the drawings. The magnetic head according to the second embodiment is different from the first embodiment in that the magnetic core 82 is formed only of the lower magnetic core, and the return yoke path 6 is a soft magnetic material having a high magnetic permeability even at a high frequency. It is characterized by being composed of a film. Other configurations are the same as those shown in FIG.

Here, the substrate 21 was made of a ceramic made of nickel, titanium, and magnesium, the gap 8 and the nonmagnetic portion 5 were made of SiO ₂ , and the conductor wire 1 was made of copper. As a magnetic film forming the magnetic core 82 and the return yoke path 86, an alloy containing iron, tantalum, and nitrogen is made of Si.
A soft magnetic film B in which O ₂ was laminated as an interlayer insulating film was used.

The right side view of FIG. 8 is as shown in FIG. 3 as in the first embodiment. In FIG. 3, electrodes 15 and 16 are provided at both ends of the conductor wire 1, respectively. Electrode 15
First pair of electrode terminals 13 and 14 leading to
Is connected via a resistor 12 to a constant-current high-frequency oscillator 11 connected in parallel via a resistor 12, and a high-frequency current (for example, 1 GHz) in which a DC current is superimposed.
Is supplied to the conductor wire 1. The second pair of electrode terminals 17
And 18 are connected to a high-frequency amplifier 19.

In this state, when the magnetic head runs on the magnetic recording medium 10 as shown in FIG. 8, the magnetic flux generated from the magnetization signal 9 of the magnetic recording medium 10 flows from the gap 8 into the magnetic head. Inflow. The magnetic permeability of the magnetic core 82 and the return yoke path 86 is 1500 at the signal frequency (for example, 20 MHz) from the medium in the magnetic core 82 using the soft magnetic film B and 1500 in the return path yoke 86 using the soft magnetic film A. 2200, which is high enough to allow the magnetic flux to pass therethrough, the magnetic flux passes through the magnetic core 82 adjacent to the conductor wire 1, enters the return path yoke 86, and forms a closed loop returning to the magnetization signal 9 of the magnetic recording medium 10. Here, as shown in FIG. 2, the magnetic permeability at a high frequency (for example, 1 GHz) is relatively high at 1050 in the magnetic core 82 and the return yoke path 86 using the soft magnetic film B, and is generated by the high frequency current. The magnetic flux of the external magnetic field passes through the loop of the magnetic core 82 and the return yoke path 86 similarly to the signal magnetic flux from the medium.

At this time, the magnetic permeability at a high frequency (1 GHz) of the magnetic core 82 adjacent to the conductor wire 1 changes mainly. As a result, the impedance of the conductor line 1 changes according to the intensity of the magnetization signal 9 generated from the magnetic recording medium due to the MI effect, and the high-frequency current is AM-modulated. A high frequency amplifier 19 connected to both ends of the electrodes 15 and 16 amplifies and detects a signal based on the AM modulation current, thereby obtaining a magnetization signal 9.
Is detected.

As in the first embodiment, a CoCrPt-based magnetic material having a surface recording density of 3.1 gigabits per 1 cm ² was used as a test magnetic recording medium, and the distance between the head and the magnetic recording medium was 1 μm. A magnetic signal recorded in advance using an inductive ring head was reproduced by the magnetic head according to the second embodiment.

As a result of examining the relationship between the magnetic field strength H due to the magnetization signal and the magnetic flux density B in the magnetic head caused by the magnetization signal, as in the first embodiment, as shown in FIG. Curve was obtained. Therefore, similarly, a bias magnetic field is applied by the DC power supply 20 shown in FIG. 3 so that the magnetic flux density B becomes the magnetic flux density Bb. When the magnetic field generated by the magnetization signal changes between the strengths H1 and H2, the input voltage of the high-frequency amplifier 19 changes between the voltages V1 and V2 to become an AM modulation signal.

The reason why the input voltage changes between the voltage V1 and the voltage V2 is as follows. That is, as the magnetic flux density B changes, the axis of easy magnetization of the magnetic core 2 deviates from the direction in which it is oriented in advance. As a result, the magnetic core 2
Is changed, the impedance of the conductor film 1 penetrating the magnetic core 2 is changed, and the high-frequency voltage applied from the high-frequency oscillator 11 of constant current is changed.

FIG. 9 is a sectional view showing a method of manufacturing the magnetic head of this embodiment.

FIG. 9A shows a soft magnetic film B having a thickness of 1 μm formed on a ceramic substrate 21 by sputtering, and a magnetic core 82 patterned by ion milling.

FIG. 9 (b) shows a metal conductor thin film in which copper is formed to a thickness of 1 μm by sputtering and the conductor wire 1 is patterned by ion milling.

FIG. 9 (c) shows a SiO ₂ film having a thickness of 0.5 μm formed as a gap material by sputtering, and the magnetic gap 8 is patterned by ion milling. Since the non-magnetic portion 5 following this also uses SiO ₂ , the pattern was extended to the portion covered by the non-magnetic portion 5. Thus, the magnetic core 82 can be protected from over-etching during the patterning of the magnetic gap 8, and the gap can be formed continuously even in the uneven portion of the magnetic core.

FIG. 9D shows a SiO ₂ film having a thickness of 2 μm formed as a non-magnetic film by sputtering, and the non-magnetic portion 5 is patterned by ion milling.

FIG. 9E shows a soft magnetic film B having a thickness of 3 μm formed by sputtering, and a return path yoke 86 patterned by ion milling.

Further, a gap depth of the head is determined by forming an alumina film of 5 μm as a protective film and wrapping the medium facing surface 7. The polished surface becomes the surface facing the magnetic recording medium 10.

In the magnetic head according to the second embodiment, since the magnetic core 82 is a so-called single core, the step of providing the upper magnetic core can be omitted, and the magnetic head can be manufactured in fewer steps than a head in which the conductor wire passes through the magnetic core. .

FIG. 10 is a sectional view showing a structural example of a magnetic head according to another embodiment of the present invention. A magnetic path portion 83 made of a soft magnetic film is provided in a portion of the magnetic core 82 not in contact with the conductor wire 1. By providing the magnetic path portion 83 when the thickness of the magnetic core 62 is thin, the magnetic flux generated from the magnetization signal 9 of the magnetic recording medium 10 smoothly passes through the magnetic path formed by the magnetic core 82 and the return path yoke 86.

In the second embodiment, FeTaN was used as the soft magnetic film. However, any soft magnetic film such as an Fe-based, Co-based metal magnetic film, or oxide magnetic film having an excellent effective magnetic permeability at high frequencies can be used. Can be used. Although the same soft magnetic material film is used for the magnetic core and the return yoke path, different films may be used. Further, although copper is used as the conductive metal film, a metal film such as Au or Ag having a small specific resistance may be used.

Although SiO ₂ is used as the gap material 8, an inorganic dielectric film such as alumina or glass may be used. Although the substrate 21 is a NiTiMg ceramic substrate, another ceramic such as AlTiC, a glass-based material, or a carbon substrate may be used. Although SiO ₂ is used as the material of the non-magnetic part 5, another non-magnetic substance may be used. Although alumina was used as the protective film, another dielectric such as SiO ₂ , a resin, or the like may be used.

In the manufacturing method, an ion milling process is mainly used as an etching method, but another etching method such as wet etching may be used. Although the film formation method was mainly performed by sputtering, a method such as vapor deposition or plating may be used.

As described above, according to the second embodiment, when forming the magnetic core and the return path yoke in the ring-type high-frequency impedance head, the magnetic core is used as one core, and the conductor wire and the non-magnetic material are connected to the return path yoke. By forming a loop of the magnetic path so as to be sandwiched by the yoke, it becomes possible to reproduce a high-density recording signal recorded on the magnetic recording medium with high sensitivity.

[0072]

As described above, according to the magnetic head of the present invention, when forming the magnetic core and the return path yoke in the ring-type high-frequency impedance head, it is possible to use soft magnetic films having different magnetic permeability. By forming a magnetic path loop so that the magnetic core is a single core and the conductor wire and the non-magnetic part are sandwiched by the return path yoke, high-density recording signals recorded on the magnetic recording medium can be reproduced with high sensitivity. Becomes

[Brief description of the drawings]

FIG. 1 is a sectional view of a magnetic head according to a first embodiment of the present invention;

FIG. 2 is a view showing the magnetic permeability of a soft magnetic film used in the magnetic head according to the first embodiment of the present invention;

FIG. 3 is an explanatory diagram of a connection state of the magnetic head according to the first embodiment of the present invention;

FIG. 4 is a characteristic diagram of the magnetic head according to the first embodiment of the present invention;

FIG. 5 is a cross-sectional view of the magnetic head according to Embodiment 1 of the present invention for each manufacturing process.

FIG. 6 is a sectional view of a magnetic head according to an embodiment of the present invention.

FIG. 7 is a sectional view of a magnetic head according to another embodiment of the present invention.

FIG. 8 is a sectional view of a magnetic head according to a second embodiment of the present invention;

FIG. 9 is a sectional view of a magnetic head according to Embodiment 2 of the present invention for each manufacturing process.

FIG. 10 is a sectional view of a magnetic head according to another embodiment of the present invention.

FIG. 11 is a perspective view showing a usage state of a conventional MI head.

FIG. 12 is a diagram illustrating the operation principle of a conventional MI head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Conductor wire 2, 82 Magnetic core 3, 83 Magnetic path part 4, 84 Magnetic sensor part 5 Non-magnetic material part 6, 86 Return path yoke 7 Medium facing surface 8 Gap 9, 54 Magnetization signal 10 Magnetic recording medium 11, 48 High frequency Oscillator 12, 49 Resistance 13, 14, 17, 18 Electrode terminal 15, 16 Electrode 19 High frequency amplifier 20, 58 DC power supply 21 Substrate 22 Lower magnetic core 23 Upper magnetic core 42 Detecting conductor film 43 Track width 44 Permalloy film 45 SiO ₂ film 46, 47 Soft magnetic core 50 Current 51, 52 Terminal 53 Magnetic recording medium 61 MI head

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hirotsugu Basuyasu 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (13)

[Claims] A first soft magnetic film formed on a substrate made of a nonmagnetic material; a conductive metal film formed so as to penetrate the first soft magnetic film; And a second soft magnetic film formed so that an end portion is in contact with the first soft magnetic film and a central portion is opposed to the first soft magnetic film via a non-magnetic material. A magnetic path of the second soft magnetic film, wherein the magnetic permeability of the second soft magnetic film is lower than the magnetic permeability of the first soft magnetic film at a frequency higher than the reproduction signal frequency. 2. A substrate comprising: a first soft magnetic film formed on a substrate made of a magnetic material; and a conductive metal film formed to penetrate the first soft magnetic film. In the above, the first soft magnetic film is formed so as to face the substrate which is a magnetic material via a non-magnetic material, so that the substrate also functions as a return path yoke, and the magnetic permeability of the substrate is reproduced. A magnetic head, wherein the magnetic permeability is lower than the magnetic permeability of the first soft magnetic film at a frequency higher than a signal frequency. 3. The magnetic head according to claim 1, wherein a high-frequency carrier signal current flows through the conductive metal film, and a direct-current bias magnetic field is applied by superimposing a direct current on the high-frequency signal current. 4. The magnetic permeability of the second soft magnetic film is less than one third of the magnetic permeability of the first soft magnetic film at the frequency of the high-frequency carrier signal. The magnetic head as described. 5. The magnetic head according to claim 2, wherein a high-frequency carrier signal current flows through the conductive metal film, and a DC bias magnetic field is applied by superimposing a DC current on the high-frequency signal current. 6. The magnetic head according to claim 5, wherein the magnetic permeability of the substrate is one third or less of the magnetic permeability of the first soft magnetic film at the frequency of the high-frequency carrier signal. 7. The magnetic head according to claim 1, wherein a nonmagnetic conductive metal film is formed on the nonmagnetic portion, and a DC current for a DC bias magnetic field is applied to the conductive metal film. 8. A first soft magnetic film formed on a non-magnetic substrate, and a conductive metal film formed on a surface of the first soft magnetic film opposite to the substrate. On the substrate, the first soft magnetic film is formed so as to be in contact with an end portion at an end portion, and a central portion thereof is opposed to the first soft magnetic film via the conductive metal film and the non-magnetic material. A magnetic head comprising a return path yoke composed of a third soft magnetic film formed as described above. 9. The magnetic head according to claim 8, wherein a high-frequency carrier signal current flows through the conductive metal film, and a direct-current bias magnetic field is applied by superimposing a direct current on the high-frequency signal current. 10. A first soft magnetic film is formed on a substrate,
Patterning a lower magnetic core; forming a conductive metal film and patterning a conductor line across the lower magnetic core; forming the first soft magnetic film; Patterning an upper magnetic core so as to sandwich a line with the lower magnetic core; and forming a non-magnetic film and patterning a gap on the magnetic core formed by the upper magnetic core and the lower magnetic core. Forming a non-magnetic material film and patterning; forming a second soft magnetic film having a magnetic permeability different from that of the magnetic core, and forming the second soft magnetic film with the magnetic core through the non-magnetic material film pattern. A method of manufacturing a magnetic head, comprising: forming a return path yoke so as to face each other. 11. A step of forming and patterning a non-magnetic film on a magnetic substrate; a step of forming a non-magnetic film and patterning a gap so as to be in contact with the non-magnetic film pattern; Forming a soft magnetic film, and patterning a lower magnetic core so as to face the magnetic substrate via the non-magnetic film pattern; and forming a conductive metal film and forming the lower magnetic core on the lower magnetic core. Patterning a conductor line so as to cross, and forming a first soft magnetic film, and patterning an upper magnetic core so as to sandwich the conductor line with the lower magnetic core. Manufacturing method of a magnetic head. 12. A step of forming a soft magnetic film on a non-magnetic substrate and patterning a magnetic core, a step of forming a conductive metal film and patterning a conductor line across the magnetic core. Forming a non-magnetic film and patterning a gap on the magnetic core; forming and patterning a non-magnetic film; forming a third soft magnetic film; A method of manufacturing a magnetic head, comprising: forming a return path yoke so as to face the magnetic core via a body film. 13. A magnetic head according to claim 1, a recording medium holding means for reproducing a recorded signal, and positioning the magnetic head at a designated position on a recording medium. And a positioning means for performing the operation.