JP3529668B2 - Magnetic reproducing element, magnetic head using the same, and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic reproducing element for reproducing information about video, audio, characters, etc. from a magnetic storage medium in which the direction and strength of magnetization are recorded and held.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for miniaturization and increase in storage capacity of magnetic storage devices due to higher storage densities. The larger the storage capacity of the storage device, the higher the speed of access to recorded information and the speed of transfer of information. In response to such a request, in a hard disk (HDD) device, for example, Japanese Patent Laid-Open No. 55-840.
Inductive type thin film magnetic heads such as those disclosed in Japanese Laid-Open Patent Publication No. 20-20 are becoming mainstream. The thin film magnetic head has a lower inductance than the bulk type magnetic head, and can perform recording and reproduction at a higher frequency.

For example, in an HDD device, the disk diameter becomes smaller due to the size reduction, and the relative speed between the head and the recording medium decreases. Therefore, it is desired to employ a magnetic flux response type magnetic head as the reproducing head. As a magnetic flux response type magnetic head, it is advantageous for narrowing the track,
An MR reproducing head using a magnetoresistive effect element (MR element) having a high reproducing output (sensitivity) per unit track width is drawing attention. Actually, this MR reproducing head is combined with an inductive thin film magnetic head for recording to form a composite type M.
The R head has been put to practical use. In order to further improve the reproduction output, research and development of a composite type MR head using a giant magnetoresistive effect element (GMR element) using a thin film material exhibiting a larger magnetoresistive effect has been actively conducted.

[0004]

In order to realize a high-density and large-capacity storage device, a technique of accurately reproducing the stored high-density information is important, and for that purpose, it has a high reproduction sensitivity. Playhead required. In this respect, the composite MR head is promising. However, when an MR element is used for the reproducing head, a shield layer and a reproducing gap are required around the MR element portion, and
It is necessary to make the film of the MR element into a single magnetic domain. Therefore, the head structure is considerably more complicated than the conventional inductive head. The more complicated the structure of the magnetic head, the more advanced manufacturing technology is required, and it becomes difficult to secure a high yield. It is an object of the present invention to provide a magnetic reproducing element having a relatively simple structure and high reproducing sensitivity, a magnetic head using the same, and a manufacturing method thereof.

The magnetic reproducing element of the present invention comprises a first non-magnetic insulating film formed on an insulating substrate, and a magnetic soft insulating film formed on the first non-magnetic insulating film and a metal soft magnetic film. With a membrane
Are alternately laminated to form a multi-layer magnetic pole core, a second non-magnetic insulating film formed on the magnetic pole core , formed on the insulating substrate, and electrically connected to both ends of the metal soft magnetic film. A conductor, a first pair of electrode terminals respectively connected to the conductor and supplying a high frequency current from an external constant current source to the conductor, and the magnitude of the external magnetic field in the magnetic pole core.
Therefore, the resistance due to the skin effect that changes according to the changing magnetic permeability
A second pair of electrode terminals, each connected to the conductor, for deriving a voltage generated by the impedance to which the resistance is added, to the outside.

According to the present invention, the impedance of the metal magnetic film changes when a magnetic field is applied to the metal soft magnetic film while a high-frequency current is flowing through the conductor. This change in impedance changes the voltage of the product of the high frequency current and the impedance. Since this change in voltage corresponds to the strength of the magnetic field, the magnetization of the magnetic recording medium can be detected as a change in voltage. For impedance of metal magnetic film
Contains the resistance due to the skin effect. Due to the skin effect
The resistance depends on the permeability, which changes depending on the magnitude of the external magnetic field.
Change due to the change in the magnitude of the magnetic field.
The change in resistance increases due to the resistance due to the skin effect.
Therefore, the detection sensitivity becomes higher.

According to another aspect of the present invention, there is provided a magnetic reproducing element in which a magnetic pole of a multilayer film formed on an insulating substrate by alternately laminating a metal soft magnetic film and a magnetic insulating film, and a magnetic pole of the multilayer film. formed, a metal soft magnetic film and the magnetic and electrical insulating film and the laminated alternately multi-layered magnetic pole cores are formed on the insulating substrate, the metallic soft magnetic film of the magnetic pole and the magnetic pole core of the multilayer film Conductors electrically connected to both ends, a first pair of electrode terminals respectively connected to the conductors for applying a high-frequency current to the conductors from an external constant current source, and the magnetic pole coil.
A) Depending on the magnetic permeability, which varies depending on the magnitude of the external magnetic field
Impeder with added resistance due to the changing skin effect
A second pair of electrode terminals respectively connected to the conductors for leading the voltage generated by the sensor to the outside.

By providing a magnetic pole of a multi-layered film in which magnetic films and non-magnetic films are alternately laminated on the main magnetic pole core, the magnetic charges at the ends of the magnetic films of the respective layers cancel each other out. Therefore, even if the width of the magnetic pole is narrow, the magnetic domain of the magnetic film is not disturbed, and the magnetic permeability can be kept high even at a high frequency. as a result,
The characteristics of the magnetic reproducing element at high frequencies are improved. metal
The impedance due to the skin effect is included in the impedance of the magnetic film.
It is rare. The resistance due to the skin effect depends on the magnitude of the external magnetic field.
Therefore, since it changes according to the magnetic permeability that changes,
The change in impedance due to the change in depth is due to the skin effect
The resistance increases, and the detection sensitivity increases accordingly.

[0009]

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described with reference to FIGS. The first embodiment relates to the structure and reproducing operation of the magnetic reproducing element of the present invention, the second embodiment relates to the structure of the magnetic head of the present invention, and the third embodiment of the present invention. The present invention relates to a method of manufacturing a magnetic head.

<< First Embodiment >> FIG. 1 is a perspective view of a magnetic reproducing element according to a first embodiment of the present invention. FIG. 3 is a graph showing the relationship between the impedance Z and the external magnetic field of the magnetic reproducing element of the present invention. FIG. 4A shows the frequency characteristic of the relative permeability of the metal soft magnetic film forming the magnetic reproducing element, and FIG. 4B shows the frequency characteristic of the output level.

In FIG. 1, the trapezoidal main magnetic pole core 2 is a single-layer thin film of a NiFe alloy, which is a metal soft magnetic material, and is formed on a nonmagnetic substrate 100 by sputtering. Nonmagnetic insulating films 1a and 1b made of a SiO ₂ film are formed on the lower surface and the upper surface of the main magnetic pole core 2 by sputtering to insulate the lower surface and the upper surface of the main magnetic pole core 2.

The conductors 3a and 3b are thin film conductors of copper (Cu), and are provided in contact with the trapezoidal oblique side surfaces of the main magnetic pole core 2. The conductors 3a and 3b are formed by vapor deposition or sputtering of copper using a predetermined mask. At this time, the upper part projects like a ridge, but this projecting part does not affect the function of this embodiment. One ends of conductor lines 9a and 9b are connected to the conductors 3a and 3b, respectively. The other ends of the conductor wires 9a and 9b are connected to the terminals 5a and 5b, respectively. A high frequency power supply 6 is connected to the terminals 5a and 5b via a resistor R, and an alternating current is supplied to the main magnetic pole core 2. As is apparent from FIG. 1, the conductors 3a and 3b are separated on the upper surface of the main magnetic pole core 2, and are electrically connected to the oblique side surface of the main magnetic pole core 2. Conductor wires 9a, 9b
The alternating current supplied through the above flows inside the main magnetic pole core 2 in the left-right direction in the drawing. Another pair of conductor wires 4a and 4b is connected to the conductors 3a and 3b. Conductor wire 4a, 4b
The impedance Z between is expressed by the equation (1).

[0014]

[Equation 1]

Assuming that the AC current flowing through the main magnetic pole core 2 is Ic, a voltage Vc which is the product of the impedance Z of the formula (1) and the AC current Ic is generated between the conductor lines 4a and 4b ("Mag
netic Recording ", Volume (・) TECHNOLOGY, C. Denis
See Mee et al, McGraw-Hill Book Company, p342).

In the equation (1), Rdc is a direct current resistance of the main magnetic pole core 2, and Reddy is a resistance due to a skin effect, which is a resistance causing so-called eddy current loss. Also, μ ',
μ ”is the magnetic permeability, S is the cross-sectional area of the magnetic film forming the main magnetic pole core 2. L is the magnetic path length, and in FIG.
Is the length in the direction of arrow 7.

The resistance Reddy resulting eddy current losses is represented by the formula (2), when the main magnetic pole cores 2 having a thickness t _mag is more than twice the skin depth [delta], the film thickness t _mag, the skin depth It is proportional to the value divided by twice the value of the length δ.

[0018]

[Equation 2]

The skin depth δ is determined by the specific resistance ρ and magnetic permeability μ of the magnetic film and the angular frequency ω of the alternating current, as shown in the equation (3).

[0020]

[Equation 3]

As can be seen from the equations (2) and (3), the higher the angular frequency ω and the magnetic permeability μ, the shallower the skin depth and the larger the resistance Reddy. The resistance Rdc is represented by the equation (4).

[0022]

[Equation 4]

Rewriting equation (1) using equations (2), (3) and (4) yields equation (5).

[0024]

[Equation 5]

The symbols a, b, and c are constant terms that are determined by the shape and material of the core without depending on the frequency or the magnetic characteristics of the main magnetic pole core 2. In Expression (5), the impedance Z increases as the product of the angular frequency ω and the magnetic permeability μ, that is, ωμ, ωμ ′, and ωμ ″ increases. As a result, the product of the alternating current Ic and the impedance Z is increased. Output voltage Vc
(Vc = Ic · Z) also becomes large.

In the magnetic reproducing element of the present embodiment, the magnetic permeability μ ′, μ ″ of the magnetic film changes according to the external magnetic field and the impedance Z changes as described above. The output voltage changes according to the change of the impedance. Since Vc changes, an external magnetic field can be detected.

FIG. 3 shows the impedance Z and the external magnetic field Hex of the magnetic reproducing element of this embodiment at a predetermined angular frequency ω.
It is a graph which shows the relationship with. When the external magnetic field Hex is zero, that is, when the value on the horizontal axis in the figure is zero, the impedance Z depends on the magnetic permeability μ of the magnetic film and the angular frequency ω of the alternating current to be conducted, as shown in Equation 5. It will be the maximum value determined. As the external magnetic field Hex increases, the magnetic film approaches saturation, and the magnetic permeability μ decreases, so the impedance Z decreases. When the magnetic film is completely saturated, the magnetic permeability μ
Becomes a very small value like the magnetic permeability of air, and the impedance Z becomes substantially equal to the DC resistance Rdc. The slope of the change in the impedance Z with respect to the external magnetic field Hex is the sensitivity. That is, as shown in Expression (6), a value k obtained by dividing the difference between the impedance Z and the DC resistance Rdc by the saturation magnetic field Hsat.
Is the sensitivity.

[0028]

[Equation 6]

As is clear from the equations (5) and (6),
Since both the output and the sensitivity are proportional to the angular frequency ω, it is desirable that the frequency of the high frequency current to be conducted be as high as possible. In general, since the magnetic permeability at high frequencies is larger than μ'in the complex magnetic permeability μ ', the shape and characteristics of the magnetic film are selected so that the resistance component in which the change in the complex magnetic permeability μ'is reflected more greatly. Preferably.

In the concrete example of the first embodiment, the film thickness (t _mag ).
Is 1 μm, the film width corresponding to the track width is 0.5 μm, and a NiFe alloy is used as the metal magnetic material.
The frequency characteristic of the magnetic permeability of the metal soft magnetic film in this example is shown by a curve C1 in FIG. The frequency characteristic of the output level is shown by the curve D1 in FIG.

<Second Embodiment> FIG. 2 is a perspective view of a magnetic reproducing element according to a second embodiment of the present invention. In the second embodiment,
On the non-magnetic substrate 100, a soft magnetic film 2 having a thickness of several microns
1A and a non-magnetic film 21 having a thickness of several hundred angstroms
B and B are alternately laminated to form a multi-layered main magnetic pole core 21. In the main magnetic pole core 21, each magnetic film 21A is magnetically and electrically separated by a non-magnetic film 21B. Due to the multilayer structure, even if the main magnetic pole core 21 has exactly the same size as that of the first embodiment, higher magnetic permeability can be obtained at a higher frequency and overcurrent loss can be reduced as compared with the first embodiment.

In FIG. 4A, a curve C2 shows the frequency characteristic of the magnetic permeability of the main magnetic pole core 21 of the second embodiment.
As is apparent from the figure, the magnetic permeability is less likely to decrease even at a higher frequency than the curve C1 of the first embodiment, and the change in magnetic permeability with frequency is small. Since it has a high magnetic permeability at a high frequency, the frequency of the high frequency power source 6 applied to the main magnetic pole core 21 can be increased. As a result, as shown by the curve D2 in FIG. 4B, the frequency characteristic of the output level is significantly improved, and the magnetization recorded at high density and high density can be detected with high sensitivity.

<< Third Embodiment >> FIG. 5 is a perspective view of a magnetic reproducing element according to a third embodiment of the present invention. The basic structure of the main magnetic pole core 21 is the same as that of the second embodiment. In this embodiment, in order to detect the magnetization of a very small area of the magnetic recording medium, a thin magnetic pole 32 serving as a magnetic flux introducing pole is provided. Generally, when the magnetic pole 32 is thinned, the magnetic charge on the end face F of the magnetic pole 32 increases the in-plane magnetic domain (90 degree domain wall) in the plane of the magnetic film of the magnetic pole 32, and the magnetic permeability of the magnetic film decreases. In this embodiment, as shown in the enlarged view of FIG. 6, the magnetic film 32A having a thickness of 50 to 500 angstroms is used.
And the non-magnetic film 32B are alternately laminated to form a magnetic pole 32.
To form. As a result, the adjacent magnetic films 32A are magnetically separated. In this embodiment, by providing the magnetic pole 32 with the protrusion 32C having a narrow width W, it can be used for a magnetic medium having a narrow track width. Such a multi-layer magnetic pole 3
In No. 2, since the magnetic charges at the end portions of the magnetic films of the respective layers cancel each other out between the multilayer films, even if the magnetic pole 32 is processed to have a narrow width W, the magnetic domains of the magnetic film are not disturbed and the magnetic permeability at a high frequency is kept high. Be drunk However, when the magnetic pole 32 of the multi-layered film is compared with that of the single-layered film having the same thickness, the cross-sectional area of the magnetic film is reduced due to the presence of the non-magnetic film, so that the absolute value of the magnetic permeability becomes low. However, in the third embodiment, the portion that functions to convert the impedance change into the voltage is the main magnetic pole core 21. Therefore, even if the absolute value of the magnetic permeability of the magnetic pole 32 is low, the magnetic flux is guided to the main magnetic pole 21 core by the magnetic pole 32 magnetized by the external magnetic field, so that the main magnetic pole 21 is magnetized by the external magnetic field even at high frequencies. Therefore, the frequency characteristic of magnetic permeability is improved.

The main magnetic pole core 21 is similar to that of the second embodiment.
The magnetic flux generated by the high-frequency current causes the main magnetic pole core 21 to move by the eddy current.
In order to prevent the magnetically sensitive parts from being localized on the surface of the
The multi-layer is formed by using the non-magnetic film 21B thicker than the magnetic pole 32. FIG. 4B is a graph showing the frequency characteristic of the reproduction output level when the reproducing head is constructed using the magnetic reproducing elements of the first, second and third embodiments. In the figure, curves D1, D2 and D3 show the frequency characteristics of the magnetic head using the magnetic reproducing elements of the first, second and third embodiments, respectively. As is apparent from the figure, the frequency characteristics of the second and third embodiments are improved as compared with the first embodiment. Comparing the first embodiment and the third embodiment,
In the third embodiment, a large output can be obtained in a high frequency range even though the film width W corresponding to the track width is made smaller than that in the first embodiment.

When the composite magnetic head is constructed by combining the magnetic reproducing element of the present invention described in each of the above embodiments with the inductive type thin film magnetic head, the magnetic flux having excellent high frequency characteristics is simpler than the conventional one. A responsive magnetic reproducing head is obtained.

<Fourth Embodiment> As a fourth embodiment of the present invention, a method of manufacturing a magnetic head will be described below with reference to the exploded perspective view of FIG. Since each element of the magnetic head of the present invention is formed of a thin film, the magnetic head can be manufactured using a film forming technique that is widely used in the field of manufacturing semiconductor devices.
The processing steps of each element in FIG. 7 will be described below in order.

A step 70A is formed on a part of the substrate 70 made of an oxide magnetic material such as ferrite by dicing. A nonmagnetic insulating film 71 such as SiO ₂ is formed on the step portion 70A by sputtering, and then the upper surface to be adhered in the drawing is flattened by lapping. A non-magnetic film of SiO ₂ having a thickness of 50 Å and a magnetic film of a NiFe alloy having a thickness of at least 100 Å are alternately stacked on the insulating film 71 by sputtering to form a convex multi-layer magnetic pole 32. Conductor layers 74a and 74b are formed on both ends of the magnetic pole 32 by sputtering of Cu or the like. The conductor layers 74a and 74b have conductors 3a formed thereon,
This is for ensuring the connection between 3b and the magnetic pole 32.

Next, the NiFe alloy magnetic film 21A and SiO
_{The two} non-magnetic films 21B are alternately laminated by sputtering, and then trapezoidal etched by ion milling to form the main magnetic pole core 21. Further, a Cu film or a Ta film is formed on the trapezoidal slope of the main magnetic pole core 21 by a sputtering method, and then the conductors 3a and 3b are formed by ion milling. At this time, the conductor lines 4a and 9a connected to the conductor 3a are simultaneously formed, and the conductor lines 4b and 9b connected to the conductor 3b are formed. Finally, the magnetic pole 77 covering the substrate 70 is formed by sputtering NiFe to complete the magnetic head. According to the manufacturing method of the present embodiment, film formation of each element of the magnetic head is performed by sputtering. Therefore, the manufacturing efficiency is high and the manufacturing cost is low.

[0039]

As is apparent from the above description of each embodiment, the magnetic head using the magnetic reproducing element of the present invention has a simpler structure than the conventional inductive magnetic head and the conventional MR magnetic head. The manufacturing process is also simpler. Therefore, it is easy to secure a relatively high yield and it is excellent in mass productivity. Further, since reproduction can be performed by the magnetic impedance effect having higher sensitivity than before, the recording density of the magnetic recording medium can be further increased. Further, since it is a magnetic flux response type like the conventional MR magnetic head, it is possible to cope with the speed reduction due to the miniaturization of the recording / reproducing apparatus.

[Brief description of drawings]

FIG. 1 is a perspective view of a magnetic reproducing element according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a magnetic reproducing element according to a second embodiment of the present invention.

FIG. 3 is a graph showing the relationship between the impedance of the magnetic reproducing element of the present invention and the external magnetic field.

FIG. 4A is a graph showing the frequency dependence of the magnetic permeability of the magnetic poles of the magnetic reproducing elements of the first and second embodiments of the invention. FIG. 4B is the graph of the first, second and third embodiments of the invention. Graph showing frequency dependence of output level of magnetic reproducing element

FIG. 5 is a perspective view of a magnetic reproducing element of a magnetic head according to a third embodiment of the invention.

FIG. 6 is an enlarged view of a magnetic pole 32 according to a third embodiment.

FIG. 7 is an exploded perspective view showing a method of manufacturing a magnetic head of the present invention.

[Explanation of symbols]

1a, 1b Non-magnetic insulating film 2 Main pole core 3a, 3b conductor 4a, 4b conductor wire 4c, 4d AC voltage output terminals 5a, 5b terminals 6 high frequency power supply 7 External magnetization 9a, 9b Conductor wire 21 Main pole core 21A magnetic film 21B non-magnetic film 32 magnetic poles 32A magnetic film 32B non-magnetic film 32C protrusion 70 board 70A step 71 insulating film 74a, 74b Conductor layer 77 magnetic pole 100 substrates

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-7-287057 (JP, A) JP-A-7-63832 (JP, A) JP-A-5-145143 (JP, A) JP-A-4- 102215 (JP, A) JP-A-8-75835 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G11B 5/33 G11B 5/31 H01L 43/08 G01R 33/09

Claims (4)

(57) [Claims] 1. A first non-magnetic insulating film formed on an insulating substrate, and a metal soft magnetic film formed on the first non-magnetic insulating film.
And a magnetic / electrical insulating film are alternately laminated to form a multilayer magnetic pole core, a second non-magnetic insulating film formed on the magnetic pole core, both ends of the metal soft magnetic film formed on the insulating substrate. A conductor electrically connected to the conductor, a first pair of electrode terminals connected to the conductor and supplying a high-frequency current from an external constant current source to the conductor, and
The transparency in the magnetic pole core that changes depending on the magnitude of the external magnetic field.
Resistance due to the skin effect that changes according to magnetic susceptibility was added
The voltage generated by impedance is derived to the outside
And a second pair of electrode terminals respectively connected to the conductors. 2. A formed on an insulating substrate, the magnetic poles of the multi-layer film formed by alternately laminating a metal soft magnetic film magnetically insulating film, formed on the magnetic poles of the multilayer film, a metal soft magnetic film and the magnetic
Electrical insulating film and the laminated alternately multi-layered magnetic pole cores, wherein formed on the insulating substrate, at both ends electrical of the multilayer film pole and the <br/> pole core of soft magnetic metal film connected conductor, are connected to the conductor, the electrode terminals of the first pair a high-frequency current is applied to the conductor from an external constant current source, and before
Magnetic permeability in the magnetic pole core that changes depending on the magnitude of the external magnetic field
The resistance due to the skin effect that changes depending on the rate is added.
Impedance, it was to derive a voltage to the outside caused by the
Because of the magnetic reproducing device having the electrode terminals of the second pair, which are respectively connected to the conductor. 3. The magnetic reproducing element according to claim 2, wherein the magnetic poles of the multi-layer film have a protruding portion facing a recording medium having a narrow track width . 4. A magnetic head having the magnetic reproducing element according to claim 1 and an inductive thin film recording element.