JPH08221704A - Magnetic head - Google Patents

Abstract

PURPOSE: To decrease noises in the boundary part between nomnagnetic materials and a magnetic gap by decreasing the inductance of a closed magnetic path and preventing the degradation in reproduced output. CONSTITUTION: This magnetic head consists of a joined body of a pair of magnetic head cores 9A, 10. Holes 8 for windings are formed between the respective magnetic head cores 9A and 10. Magnetic metallic films 14A, 14B are formed on the opposite surface sides of the respective magnetic head cores. A track working part 3 is formed on the magnetic recording surface side of the joined body. The one magnetic head core 10 is formed out of a magnetic material 7. The other magnetic head core 9A is composed of a magnetic material part 5 and a nonmagnetic material part 2. The magnetic material part 5 is formed on a track working part 3 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head particularly suitable for use in a floating magnetic head core slider.

[0002]

2. Description of the Related Art In a fixed magnetic disk device, a flying type magnetic head core slider includes a so-called composite type. In this type, a slider main body having an air bearing portion and a core chip are separately prepared, and these are combined and integrated to manufacture a magnetic head. According to this type of magnetic head, compared with the monolithic type, the thickness of the core for recording / reproducing, and hence the inductance can be reduced, and the high frequency characteristics can be improved.

Various types of magnetic heads are known. For example, in a so-called DMIG type magnetic head, a metal magnetic film is formed on each of the facing surfaces of a so-called C-type core and an I-type core, and then the C-type core and the I-type core are joined. Both the C-type core and the I-type core are made of ferrite. In particular, such a type of magnetic head has become the mainstream in a magnetic disk device.

In Japanese Patent Laid-Open No. 3-46104,
The I-shaped core is formed of crystallized glass, and the metal magnetic film is formed on this. Thereby, the thermal expansion coefficient and the like of the I-type core and the metal magnetic film are matched. JP-A-5-1
In Japanese Patent No. 43926, the I-type core is formed as a laminated body of a magnetic body and a non-magnetic body, in which case a metal magnetic film is formed on the magnetic body and a non-magnetic body portion is provided outside the magnetic body. ing. As a result, the inductance of the magnetic head is reduced and the read / write output is increased as much as possible. According to Japanese Patent Laid-Open No. 6-215312, both the C-type core and the I-type core are made of non-magnetic material.

[0005]

However, in the DMIG type magnetic head, each magnetic core made of ferrite and the metal magnetic film form a closed magnetic path.
Since the inductance increases, the number of coil turns cannot be increased. The present inventor also studied a technique of forming an I-type core from crystallized glass and forming a metal magnetic film on the I-type core. However, in this magnetic head, it was found that noise is generated at this boundary because the magnetic flux changes greatly at the boundary between the crystallized glass and the metal magnetic film. Moreover, the thinner the metal magnetic film and the closer the crystallized glass to the magnetic gap, the larger the noise at this boundary. Moreover, it has been found that when the metal magnetic film is made thin, the magnetic flux flowing in the closed magnetic path becomes too small, and the reproduction output decreases.

Even when the C-type core and the I-type core are both made of a non-magnetic material, there still remains a problem of noise generated at the boundary between the magnetic film and the non-magnetic material and a problem of reduction in reproduction output. there were. In addition, it is particularly necessary to form the metal magnetic film also on the facing surface side of the C-shaped core, and this forming method is usually the vapor deposition method or the sputtering method. However, when the metal magnetic film is formed by such a vapor phase method, the facing surface of the C-shaped core has a slope as described below, and the metal magnetic film is inevitably formed on this slope. Difficult to attach,
The thickness becomes thin. After forming the metal magnetic film, the attached elements are rearranged by an annealing process.
At this time, the internal stress of the metal magnetic film tends to increase at the sloped portion. On the other hand, in the above magnetic head, both the C-shaped core and the I-shaped core are made of a non-magnetic material,
The metal magnetic film forms a closed magnetic circuit. As a result, especially in the portion on the slope of the metal magnetic film, it becomes difficult for the magnetic flux to pass therethrough, and the reproduction output further decreases.

An object of the present invention is to form a bonded body of a pair of magnetic head cores, in which winding holes are formed between the magnetic head cores, and a metal magnetic film is formed on the facing surface side of each magnetic head core. In the magnetic head in which the track processing portion is formed on the magnetic recording surface side of the bonded body, the inductance of the closed magnetic path is reduced to prevent the reproduction output from being lowered, and the noise at the boundary between the non-magnetic body and the magnetic film is prevented. Is to prevent.

[0008]

The present invention comprises a bonded body of a pair of magnetic head cores, a winding hole is formed between each magnetic head core, and a metal magnetic film is formed on the facing surface side of each magnetic head core. A magnetic head having
One of the magnetic head cores is made of a magnetic material, and the other magnetic head core is made of a magnetic material portion and a non-magnetic material portion. Here, the magnetic material portion is formed on the magnetic recording surface side. Characterize.

[0009]

The present inventor has made various studies on the form of the magnetic head as described above. In this process, one magnetic head core is formed of a magnetic material, and the other magnetic head core is formed as a magnetic material portion. It has been conceived that it is formed of a non-magnetic material portion and that the magnetic material portion is formed on the magnetic recording surface side.

As a result, since the core of one of the magnetic head cores is made of a magnetic material, magnetic flux passes not only to the metal magnetic film but also to the magnetic material, and this magnetic material portion also constitutes a magnetic circuit. .

At the same time, the magnetic recording surface side of the other magnetic head core is made of a magnetic material. As a result, the change in the magnetic flux was reduced at the boundary between the magnetic head core and the magnetic gap on the magnetic recording surface side, and the noise at this boundary was reduced. Moreover, since the opposite side is formed of a non-magnetic material, it contributes to the reduction of the inductance as a whole.

Further, in manufacturing the magnetic head of the present invention, the bonded body of the magnetic head core needs to be track-processed, but the magnetic body portion of the magnetic head core can be formed on the track-processed portion side. That is, crystallized glass or calcium titanate is generally used as the non-magnetic material forming the magnetic head core. However, since these materials have a small Young's modulus or are easily cracked, the grindstone for grinding is likely to be clogged during track processing, which makes track processing difficult. However, since the magnetic material portion is provided in the track processing portion, the non-magnetic material portion does not exist in the track processing portion, or even if it exists, it is only at the end portion thereof, so that the track processing is very easy to perform.

[0013]

In the present invention, the entire track processed portion is composed of a magnetic material portion, and the boundary between the magnetic material portion and the non-magnetic material portion is located in the region between the track processed portion and the winding hole. It is preferably formed. This makes it easier to perform track processing. In addition, since the track processed portion has a narrow width, it is difficult for the magnetic flux to pass when viewed from the shape, while the magnetic body naturally allows the magnetic flux to pass easily. On the other hand, the opposite can be said for the body portion under the track processing portion.
Therefore, the magnetic flux easily passes through the magnetic head core as a whole.

Here, in the case where the track processing portion is formed as a plate-like portion extending vertically from the main body portion of the magnetic head, particularly between the track processing portion and the main body portion,
The dimension in the width direction decreases rapidly. Therefore, if a part of the track processing part is made of a non-magnetic material,
Since the magnetic flux suddenly becomes hard to pass through this boundary portion, the reproduction output may be reduced. So in this case,
In particular, it is preferable to form the entire track processed portion with a magnetic material.

Further, in a preferred aspect of the present invention, the track processing portion has an inclined surface extending from the main body portion of the magnetic head to the magnetic recording surface, and the thickness of the track processing portion is the main body of the magnetic head. It smoothly decreases from the portion toward the magnetic recording surface. As a result, the dimensional change at the boundary between the track processing portion and the main body portion becomes small, so that the obstacle to the passage of the magnetic flux at this portion becomes small. However, even in this case, it is still more preferable that the entire track processed portion is formed of a magnetic material.

Further, in the track processing for manufacturing the magnetic head of the present invention, an inclined surface extending from the main body portion of the magnetic head to the magnetic recording surface is formed, and the thickness of the track processed portion is set to the main body of the magnetic head. If it is smoothly reduced from the portion toward the magnetic recording surface, the track processing is relatively easy to perform even if the non-magnetic material is present in this portion.

The magnetic material is preferably ferrite such as Mn-Zn ferrite, and the metal magnetic film is Fe-T.
A-N alloy, sendust, etc. are preferred.

FIG. 1 is a perspective view showing a magnetic head 1 according to an embodiment of the present invention. The magnetic head 1 is composed of a joined body of one magnetic head core 10 and the other magnetic head core 9A. One magnetic head core is a so-called C-type core, and the other magnetic head core is a so-called I-type core. A winding hole 8 is formed between the C-shaped core 10 and the I-shaped core 9A.

A metal magnetic film 14 is formed on the facing surface of the I-shaped core 9A.
A is formed, and a metal magnetic film 14B is formed on the facing surface of the C-shaped core 10. A reinforcing glass layer 6 is formed on the apex portion. FIG. 1 of this magnetic head 1.
A plate-shaped track processing portion 3 is formed on the upper side of. The entire C-shaped core 10 is formed by the magnetic body 7. The track processed portion side of the I-shaped core 9A is the magnetic material portion 5, and the opposite side is the non-magnetic material portion 2. The portion of the I-shaped core 9A existing in the track processing portion 3 is entirely made of a magnetic material, and the magnetic material portion 5
The boundary 4 between the non-magnetic material portion 2 and the non-magnetic material portion 2 exists in the region between the track processing portion 3 and the winding I-type core 8. That is,
The magnetic material portion is a plate-like portion 5b in the track processing portion 3.
And a wide flat portion 5a on the main body side.

In such a magnetic head, in particular, when the metal magnetic film 14B of the C-shaped core 10 is formed by the vapor phase method, a portion where a magnetic flux is hard to pass is inevitably formed in the metal magnetic film. However, by forming the entire C-shaped core 10 with a magnetic material, it is possible to solve the problem that magnetic flux is difficult to pass through the metal magnetic film 14B. On the other hand, in the I-type core 5, since the metal magnetic film 14A is formed on substantially the same plane, the problem that the magnetic flux does not easily pass as described above does not occur. Therefore, the non-magnetic part 2 is used. However, it is possible to prevent the reproduction output of the entire magnetic head from decreasing.

FIG. 2 shows a magnetic head 15 according to another embodiment.
It is a perspective view which shows A. The magnetic head 15A is composed of a joined body of a C-shaped core 17 and an I-shaped core 16A. C-type core 1
The whole 7 is formed by the magnetic body 7. The I-shaped core 16A includes a magnetic material portion 11A and a non-magnetic material portion 2. The track processing portion 13 includes the inclined surface 12 extending from the main body portion of the magnetic head 15A toward the magnetic recording surface 18, and the thickness of the track processing portion 13 extends from the main body portion of the magnetic head toward the magnetic recording surface 18. It is decreasing smoothly.

The boundary 4 between the non-magnetic material portion 2 and the magnetic material portion 11A exists in the main body portion below the track processing portion 13, and the portion of the I-shaped core 16A in the track processing portion 13 is: All are made of magnetic material.

FIG. 3 shows a magnetic head 15 according to another embodiment.
It is a perspective view which shows B. The magnetic head 15B is composed of a joined body of a C-shaped core 17 and an I-shaped core 16B. C-type core 1
The whole 7 is formed by the magnetic body 7. The I-shaped core 16B is composed of a magnetic material portion 11B and a non-magnetic material portion 2A. The track processing portion 13 includes the inclined surface 12 extending from the main body portion of the magnetic head 15B to the magnetic recording surface 18, and the thickness of the track processing portion 13 extends from the main body portion of the magnetic head to the magnetic recording surface 18. It is decreasing smoothly.

The boundary 4 between the non-magnetic material portion 2A and the magnetic material portion 11B exists on the lower side of the track processing portion 13, and most of the portion of the I-shaped core 16B inside the track processing portion 13 is present. Although it is made of a magnetic material, its lower end is made of a non-magnetic material.

An example of the flying type magnetic head core slider is shown in the perspective view of FIG. First, the magnetic head core slider 22 and the magnetic head core 1 shown in FIG.
Create separately. The slider 22 is made of nonmagnetic polycrystalline ceramics. A pair of rail-shaped air bearing portions 21A and 21B are provided on the upper surface of the slider 22. In the slider 22, a coil winding groove 24 and an insertion hole 23 are formed at one end in the sliding direction of the magnetic disk. The magnetic head 1 having the track portion is inserted into the insertion hole 23. A stick (not shown) made of a binder for sealing is placed on the track portion 3,
This rod is heated and melted, the binder is poured into the insertion hole 23, and the magnetic head 1 is fixed to the slider 22. Next, the air bearing portion 21 of the slider 22
A and 21B are polished, but at the same time, the gap depth of the track portion 3 of the magnetic head 1 is adjusted. Of course, the magnetic heads shown in FIGS. 2 and 3 can also be attached to the magnetic head core slider in this way.

The experimental results of manufacturing the magnetic head 1 shown in FIG. 1 will be described below. First, a C type core substrate and an I type core substrate were prepared. As shown in FIG. 5A, a rod-shaped magnetic material 25 and a non-magnetic material 26 are prepared, and
Both are joined as shown in (b). And FIG.
As shown in (c), this joined body was cut along an imaginary line indicated by an arrow A to obtain a joined body shown in FIG. 6 (d). Further, as shown in FIG. 6A, a C-shaped core substrate 27 having a predetermined shape was prepared. As these magnetic materials, Mn-
Zn ferrite is used, and as a non-magnetic material, the same coefficient of thermal expansion (α = 11) as this Mn-Zn ferrite is used.
A crystallized glass with 0 × 10 ⁻⁷ / ° C.) was used. The step of joining the magnetic material 25 and the non-magnetic material 26 was performed at 800 ° C. for 30 minutes in a nitrogen atmosphere.

The C-shaped core substrate 27 shown in FIG. 6A is lapped, and the C-shaped core substrate 2 is lapped as shown in FIG. 6B.
The metal magnetic film 14B was formed on the facing surface of No. 7. Fe-Ta-N alloy (Bs1.5T) is used as the metal magnetic film 14B.
Was sputtered to a thickness of 6 μm. As shown in FIG. 6C, the bonding glass layer 28B was formed on the metal magnetic film 14B. As the glass layer for bonding, a SiO ₂ layer having a thickness of 500 Å,
A glass paste having a thickness of 500 Å was formed by sputtering.

The I-shaped core substrate shown in FIG. 6 (d) is composed of a joined body of a magnetic material portion 29 and a non-magnetic material portion 30. This is lapped, and as shown in FIG. 6 (e), an Fe-Ta-N alloy (Bs1.5 is formed on the facing surface of the I-type core substrate).
T) was formed. At this time, sputtering was performed so that the thickness was 6 μm. As shown in FIG. 6F, the bonding glass layer 28A was formed on the metal magnetic film 14A. As the bonding glass layer, a SiO ₂ layer having a thickness of 500 Å and a glue glass having a thickness of 500 Å were formed by sputtering.

The reinforcing glass is set in the apex portion, and the I-type core substrate and the C-type core substrate are set at 1 at 550 ° C.
Bonding was performed in a nitrogen atmosphere for a time to obtain a bonded body or a gap bar shown in FIG. Cut this gap bar,
The joined body shown in FIG. 7 (b) was obtained. Here, the C-shaped core material 3
2 and the I-shaped core material are joined together, and the I-shaped core material is composed of the magnetic material portion 31 and the non-magnetic material portion 2.

The thickness of the metal magnetic film on the I-shaped core is preferably 6 μm or more, especially considering that the magnetic circuit is composed of only the metal magnetic film in the non-magnetic portion.

The bonded body was track processed to manufacture the magnetic head 1 shown in FIG. 1. The magnetic head core slider was assembled as shown in FIG. 4 and the air bearing portion was processed. During this track processing, # 5000
The width of the track part is 4.5 by using the diamond whetstone of
μm. In the I-type core, the boundary 4 between the magnetic material portion and the non-magnetic material portion is provided 50 μm below the apex portion, and the specified depth of the track processing portion is 3 of the apex portion.
It was set to 0 μm below. Therefore, the boundary 4 is located below the track processing portion. When the characteristics of this magnetic head were examined, the inductance was 0.8 μH and 31 turns.

On the other hand, in Comparative Example 1, in the magnetic head having the shape shown in FIG. 1, when each magnetic head core was formed of ferrite, the inductance was 1 μH and 31 turns.

Therefore, it can be seen that the magnetic head of the embodiment of the present invention has a greatly reduced inductance. Moreover, regarding the reproduction output, the magnetic head according to the above-described embodiment of the present invention and the magnetic head of Comparative Example 1 were equivalent.

As Comparative Example 2, in the magnetic head of FIG. 1, when the entire I-shaped core was formed of calcium titanate which is a non-magnetic material, the inductance was about 0.8 μH and 31 turns. It was However, the reproduction output was reduced by about 10% with respect to both Comparative Example 1 and the magnetic head of the present invention. Further, in this magnetic head, noise of about 5% of the reproduction output was generated at the boundary between the I-shaped core made of a non-magnetic material and the magnetic gap. Further, when the entire I-shaped core is formed of calcium titanate which is a non-magnetic material, the grinding stone is clogged during the track processing, so that the processing requires a long time.

As described above, in the magnetic head of the present invention, the reproduction output does not decrease even when compared with the magnetic head of Comparative Example 1 because the area of the track processed portion is made of ferrite, so that the magnetic resistance is increased. It seems that there is almost no.

A magnetic head 15A shown in FIG. 2 was prototyped and the same experimental results as above were obtained.

[0037]

As described above, according to the present invention, in the magnetic head as described above, the inductance of the closed magnetic circuit is reduced, the reproduction output is prevented from being lowered, and the boundary between the non-magnetic material and the magnetic gap is reduced. The noise in the part could be reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a magnetic head 1 according to an embodiment of the invention.

FIG. 2 is a perspective view showing a magnetic head 15A according to another embodiment of the present invention.

FIG. 3 is a magnetic head 15 according to still another embodiment of the present invention.
It is a perspective view which shows B.

FIG. 4 is a perspective view schematically showing a state in which the magnetic head 1 is attached to a predetermined position of the magnetic head core slider 22.

FIG. 5 (a) is a rod-shaped magnetic material 25.
And (b) is a perspective view showing the non-magnetic material 26 and
It is a perspective view which shows the joined body of the magnetic body material 25 and the non-magnetic body material 26, (c) is a perspective view for showing the direction which cut | disconnects this joined body.

6 (a), (b) and (c) are perspective views sequentially showing a process of processing a C-shaped core substrate, and (d),
(E) And (f) is a perspective view which shows the processing process of the board | substrate for I type cores one by one.

7A is a circuit diagram of the C-shaped core substrate of FIG. 6C and FIG.
It is a perspective view which shows the joined body with the board | substrate for I type cores of (f), and (b) is a perspective view which shows the magnetic head material obtained by cutting the joined body of (a).

[Explanation of symbols]

1, 15A, 15B Magnetic head 2, 2A Non-magnetic part of I-type core 3 Vertically extending plate-shaped track processing part 4 Boundary between magnetic part and non-magnetic part
5 Magnetic part of I type core 6 Glass for reinforcement 7
Magnetic material 8 Winding hole 9A, 16A, 16B
I-type core 10, 17 C-type core 11A, 11
BI Magnetic part of I-type core 12 Sloping surface of track processing part 13 Track processing part 14A, 14B
Metal magnetic film 22 Magnetic head core slider 2
7 C-type core substrate 28A, 28B bonding glass layer

Claims (4)

[Claims] 1. A joined body of a pair of magnetic head cores,
A magnetic head in which a winding hole is formed between each of the magnetic head cores, and a metal magnetic film is formed on the facing surface side of each of the magnetic head cores, wherein one of the magnetic head cores is a magnetic body. The magnetic head core is formed of a magnetic material portion and a non-magnetic material portion, and the magnetic material portion is formed on the magnetic recording surface side. . 2. A track processed portion is formed on the magnetic recording surface side, the entire track processed portion is constituted by the magnetic material portion, and the boundary between the magnetic material portion and the non-magnetic material portion is the above-mentioned. It is formed in the area | region between a track processing part and the said hole for windings, It is characterized by the above-mentioned.
The magnetic head described. 3. The magnetic head according to claim 1, wherein the track processing portion is formed as a plate-shaped portion extending vertically from a main body portion of the magnetic head. 4. The track processing portion has an inclined surface extending from the main body portion of the magnetic head toward the magnetic recording surface, and the thickness of the track processing portion is from the main body portion of the magnetic head to the magnetic recording. The magnetic head according to claim 1, wherein the magnetic head is smoothly reduced toward the surface.