JPS63306505A - Production of composite type magnetic head core - Google Patents

Abstract

PURPOSE:To prevent the generation of a contour effect based on a reproducing output and to improve the accuracy of track width by embedding a nonmagnetic material in track width regulating grooves on the abutting face of a ferrite block. CONSTITUTION:The grooves 32 for regulating track width are formed on a magnetic gap forming portion on the gap-opposed face (abutting face) 31a of the ferrite block 31. After embedding the nonmagnetic material 33 in the grooves, unnecessary nonmagnetic material parts on the face 31a are removed and a track part held between two grooves 32 is exposed, so that a ferrite block 31 embedding the nonmagnetic material 33 only in the grooves 32 can be obtained. A coupling interface between ferrite and metallic magnetic materials 37, 37' is inclined from the magnetic gap 41 to form rugged structure. Consequently, the contour effect can be neglected and the magnetic head cores with highly accurate track width can be mass-produced.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a method of manufacturing a core for a composite magnetic head, and particularly to a magnetic head suitable for recording and reproducing high frequency signals such as a VTR, particularly for high coercive force media. The present invention relates to a method for advantageously manufacturing a core for a composite magnetic head, which provides a composite magnetic head suitable for use in a composite magnetic head.

(Background Art) In high-density magnetic recording and reproducing devices, it is known that it is advantageous to increase the coercive crab Hc of the magnetic recording medium, but in order to record information on a magnetic recording medium with high coercive force, , it is necessary to strengthen the leakage magnetic field from the magnetic head.

However, the ferrite material currently used for the core that constitutes the magnetic head has a saturation magnetic flux density: B of 40
00 to 5,000 Gauss, there is a limit to the strength of the recording magnetic field that can be obtained, and if the coercive force of the magnetic recording medium exceeds 1,000 Oersteds, there is a drawback that recording becomes insufficient.

On the other hand, magnetic heads using crystalline alloys or amorphous alloys such as Fe-/1t-3i alloy (Sendust), N1-Fa gold alloy Permalloy, which are collectively called metal magnetic materials,
In general, it has superior properties such as higher saturation magnetic flux density and lower sliding noise than ferrite materials. However, the track width used for -a (more than 10 μm)
, the effective permeability in the video frequency region is lower than that of ferrite due to eddy current loss, resulting in a reduction in reproduction efficiency. Furthermore, in terms of wear resistance, it is several steps inferior to ferrite.

Therefore, in order to solve the above-mentioned problems, a composite magnetic head core has been proposed that combines ferrite and metal magnetic material to take advantage of the advantages of both.

For example, as shown in FIG. 1, which is a perspective view of one core for such a composite magnetic head, core portions 1, 1'
The core for a composite magnetic head has a structure in which the core is made of ferrite with high magnetic permeability, and the part near the magnetic gap 5, which is the main part of the recording action, is made of a metal magnetic material 2.2' formed by physical vapor deposition such as sputtering. is proposed. In this magnetic head core, for high-density recording, the track width is narrowed, and cutout grooves 7, 7 for narrowing the track width are provided on both sides near the magnetic gap 5, and non-magnetic material is used for reinforcement therein. 3 is filled. Note that 6 is a window (hole) for the coil@wire. FIG. 2 shows a plan view of the surface facing the recording medium of the conventional magnetic head core.
It has been recognized that there is a drawback in that the coupling boundary portions 4, 4' between the ferrite core portions 1, 1' and the metal magnetic materials 2, 2' act as a pseudo gap, impairing recording and reproducing characteristics. In particular, the coupling boundary 4.4' and the magnetic gap 5
When these lines become parallel, a considerable amount of signal is picked up at the boundary, which creates a problem in that the so-called contour effect becomes severe, causing undulations in the frequency characteristics of the reproduced output.

Further, as another core for a composite magnetic head, a structure as shown in FIG. 3 is also known. The magnetic head core shown in FIG. 3 is made by forming a metal magnetic material 12 having a high saturation magnetic flux density on a non-magnetic substrate 11 by physical vapor deposition such as sputtering or vacuum deposition to a film thickness equal to the track width. After bonding a non-magnetic material 11' with a glass thin film thereon, it is divided into three equal parts and the gap abutting surfaces are wrapped, and then a coil winding window 13 is formed, and a predetermined non-magnetic film is applied to the gap abutting surfaces. However, such magnetic head cores have the following problems. That is, when the track width is as large as 20 μm or more, a single layer of the metal magnetic material 12 has poor high frequency characteristics due to eddy current loss, so it is necessary to form a multilayer structure with a non-magnetic material interposed therebetween. Compared to the magnetic head core shown in the figure, the area where the metal magnetic material 12 is formed per core is larger, which is unproductive.Furthermore, the track width is determined by the film thickness of the metal magnetic material 12. Therefore, film thickness accuracy within a batch is strictly required, and there are inherent problems in that assembly of the magnetic head core is extremely complicated.

Further, Japanese Patent Application Laid-Open No. 58-155513 proposes a core for a composite magnetic head having a structure as shown in FIGS. 4(a) and 4(b). This magnetic head core is
Two high magnetic permeability ferrite blocks 21, each having a protrusion with a protruding cross-sectional shape on the surface facing the magnetic recording medium.
A magnetic material 22 and 22' having a higher saturation magnetic flux density than ferrite is adhered to at least both sides of the protruding part 21',
At the tip of the protrusion, through the magnetic gap 23,
The magnetic bodies 22 and 22' face each other, and the width of the ferrite at the tip of the protrusion is smaller than the track width. Note that 25 and 26 indicate a non-magnetic buried material and a coil winding window, respectively.

In the case of such a structure, ferrite 21.21
' and the boundary joint part 24.24 of the metal magnetic material 22.22'
' is largely inclined with respect to the magnetic gap 23, which has the advantage of not having the contour effect of the reproduction output as in the magnetic head core shown in FIG. 1, but the strength of the protrusion of the ferrite block is weak. In addition, it is difficult to obtain the desired shape, and the track width tends to fluctuate depending on the amount of polishing of the surface on which the magnetic gap 23 is formed, so it is also difficult to obtain precision in the track width, resulting in a low yield and poor mass productivity. is inherent.

Furthermore, in JP-A-61-265714 and JP-A-61-273706, a core for a composite magnetic head made of a combination of ferrite and a metal magnetic material is disclosed. By providing uneven parts on the
A structure in which the concavo-convex portions on the left and right core portions are asymmetrically arranged, and in which at least one minute gap extending toward the magnetic gap portion is formed in the magnetic material has been revealed. The core for such a magnetic head is
It is manufactured as follows.

That is, a resist film with striped slits is applied to a predetermined ferrite block and etched to form a ferrite block with a corrugated surface. After forming a magnetic layer made of a magnetic metal material and polishing its surface to make it a flat surface, a plurality of grooves that define the track width are formed parallel to each other, and then grooves for coil winding are formed. After that, the two ferrite blocks are combined and joined to form an integral assembly, and this ferrite block assembly is then cut at a predetermined position to form the desired composite magnetic head. A manufacturing method has been revealed in which the cores are cut out one after another.

However, in the manufacturing method of such a core for a composite magnetic head, a non-magnetic material (glass) is poured into the track width defining groove after forming a magnetic layer made of a metallic magnetic material. It has the following problems. That is, when the metal magnetic material is an amorphous alloy or a permalloy alloy, such magnetic material
When heated above 0°C, its magnetic properties deteriorate, and in the case of amorphous alloys in particular, they crystallize and deteriorate significantly, so glass must be poured into the track width defining groove at a temperature below 500°C. Therefore, low melting point glass must be used.In the case of low melting point glass, - not only does it have difficulty in abrasion resistance during sliding of the magnetic recording medium, but also has low strength and is difficult to grind. However, it has the disadvantage of causing chips when cutting.

In addition, when the metal magnetic material is sendust, there is no problem that its magnetic properties deteriorate by pouring the high melting point glass as described above, but if it is heated to 500°C or higher, for example 700 to 800°C or higher, Due to the large difference in thermal expansion coefficient with ferrite (Sendust: 150xlO-'
, ferrite: 110~120 Alternatively, problems such as cranking or peeling may occur during subsequent grinding or cutting processes.

In any case, there is no practical way to manufacture a core for a composite magnetic head, which involves forming a magnetic film made of a magnetic metal material and then pouring a non-magnetic material (glass) into the track width defining groove. There were several drawbacks to this method, and it could not be advantageously adopted industrially.

(Object of the Invention) The present invention has been made in view of the above circumstances, and its purpose is to solve the problems in the conventional composite magnetic head core and its manufacturing method. The present invention provides a core for a magnetic head that exhibits excellent recording and reproducing characteristics even on high coercive force recording media, and provides an easy manufacturing method thereof.In particular, it facilitates improvement of track width accuracy, and utilizes lithography technology and etching. The object of the present invention is to advantageously manufacture a core for a composite magnetic head without a contour effect in the reproduction output by making the bonding interface between the ferrite and the metal magnetic material oblique to the magnetic gap using technology.

(Structure of the Invention) In order to achieve this object, the present invention abuts first and second ferrite blocks to form an annular magnetic path, and at the same time, a predetermined gap is formed between the abutting portions of the ferrite blocks. In a method for manufacturing a core for a magnetic head using a combination body formed with a magnetic gap, (a) a track is formed on at least the magnetic gap forming portion of the abutting surface of at least one of the two ferrite blocks with respect to the other ferrite block; a first step of forming at least two mutually parallel grooves that define a width in a direction parallel to the abutment surface and perpendicular to the magnetic gap; (b) forming the track width defining groove; a second step of applying a predetermined non-magnetic material to the abutting surfaces of the ferrite blocks and embedding the non-magnetic material in the track width defining groove; a third step of removing an unnecessary portion of the magnetic material to expose a track portion sandwiched between the track width defining grooves; and (d) forming a track width defining groove in which a portion of the track portion has a predetermined width; A predetermined resist film is formed on the abutting surfaces of the ferrite blocks so as to be exposed as at least one exposed portion extending in the direction, and then the track portion is etched through the exposed portion to form an uneven surface. a fourth step; <e) a fifth step of depositing a predetermined metal magnetic material on the etched abutment surfaces of the ferrite block; (f) a fifth step of depositing a predetermined metal magnetic material on the etched abutment surfaces of the ferrite block; A portion with a predetermined thickness is removed to expose the non-magnetic material buried in the track width defining groove while leaving the adhesion layer of the metal magnetic material formed on the uneven surface of the track portion at a predetermined thickness. (g) prior to or after the sixth step, forming a groove for coil winding on the abutting surface of at least one of the first and second ferrite blocks; and (h) applying a nonmagnetic layer of a predetermined thickness to at least the magnetic gap forming region of the abutting surface of at least one of the first and second ferrite blocks that have undergone the first to seventh steps. an eighth step of forming (i
) a ninth step in which the magnetic gap forming portions of the abutting surfaces of the first and second ferrite blocks that have completed the eighth step are opposed and joined to each other to be integrated; (j) such joining is integrated; A tenth step of cutting the first and second ferrite block combination at predetermined positions to obtain at least one composite magnetic head core. The law is its gist.

According to an embodiment of the method of the present invention,
In the fourth step, the exposed portions include:
Curved or curved surfaces that are formed on the track portion at predetermined intervals and that form part of a waveform in the width direction of the track portion by etching the track portion through the plurality of exposed portions. is formed, thereby forming a surface inclined with respect to the magnetic gap.

Further, in the method of the present invention, prior to the fifth step, at least the surface of the exposed track portion of the abutting surface of the ferrite block is coated with ferrite constituting the track portion. An operation for forming a glass layer that brings the metal magnetic material into close contact with the metal magnetic material will be performed as necessary.

(Specific Structure and Embodiments of the Invention) In the present invention, the first and second ferrite blocks that provide the combination used to manufacture the target composite magnetic head core are conventionally used. A ferrite material with high magnetic permeability is used, and generally it is used as a long plate-shaped block of a predetermined thickness so that a plurality of cores for magnetic heads can be manufactured, and by butting them together, a ring-shaped magnetic path is formed. It is configured. Note that this high permeability ferrite block is made of Mn.
- Single crystals or polycrystals such as Zn ferrite, Ni-Zn ferrite, or composites thereof are used, and in particular when using a single crystal, the (100)
, (110), (311).

A crystal plane such as (332) is advantageously selected as the gap facing surface (ferrite block abutting surface).

In the present invention, first, in the first step,
At least two grooves parallel to each other defining a track width are provided in at least the magnetic gap forming region of the abutting surface of at least one of the two ferrite blocks against the other ferrite block, in a direction parallel to the abutting surface and with the magnetic gap. are formed in orthogonal directions.

By the way, FIG. 5(a) shows an example in which a plurality of grooves 32 defining a track width are formed in a magnetic gap forming region on a gap facing surface (abutting surface) 31a of a predetermined high magnetic permeability ferrite block 31. However, as shown in FIG. 5(a), this track width defining groove is formed only at the ridge of the ferrite block 31 (magnetic gap formation region), and as shown in FIG. 5(b), There is no problem even if the groove 32' is formed to pass through to the rear part of the core (the part opposite to the magnetic recording medium facing surface 31b).The groove shape of the track width defining groove 32 and 32' is as follows. The shape is selected as appropriate, for example, as shown in FIGS. 6(a) and 6(b), but even if the amount of polishing of the gap facing surface 31a is changed in the subsequent process, the track width will not fluctuate. A small groove shape, that is, a groove shape as shown in FIG. 6<a> having a straight portion perpendicular to the gap facing surface 31a is more preferably adopted than the groove shape of FIG. 6(b).

In this way, as shown in FIG. 7, the ferrite block 31 provided with the track width defining groove 32 has a gap facing surface 31a formed with the track width defining groove 32 as a second step. Predetermined non-magnetic material 3 on top
3 is applied, and the non-magnetic material 33 is buried and filled in the track width defining groove 32 as well. Note that this non-magnetic material 33 may be made of glass, ceramic-based inorganic adhesive, hard resin, or the like, but glass is suitable from the viewpoint of stability such as running performance of the magnetic recording medium.

Next, after embedding the non-magnetic material 33 in the track width defining groove 32 in this manner, at least the unnecessary portion of the non-magnetic material 33 on the gap forming surface 31a of the ferrite block 31 is removed to define the track width. The track portion sandwiched between the grooves 32 and 32 is exposed (third step).To remove the unnecessary portion of the non-magnetic material 33, a method of grinding it away with a grindstone is generally adopted. By the removal operation, a predetermined thickness portion of the gap facing surface 31a of the ferrite block 31 is removed. Through such a removal operation, a ferrite block 31 in which the non-magnetic material 33 is buried only in the track width defining groove 32 is obtained, as shown in FIG.

In the fourth step, a ferrite block 31 is formed in which a predetermined non-magnetic material 33 is embedded in the track width defining groove 32.
On the other hand, as shown in FIG. 9, a predetermined resist film 34 is formed on the gap facing surface 31a where the track portion is exposed, leaving a part of the track portion. That is,
A resist film 34 is formed on the gap-opposing surface 31a of the ferrite 31 so that a part of the track portion is exposed as at least one exposed portion (35) extending in the formation direction of the track width defining groove 32 with a predetermined width. It is.

Note that the patterning of the resist film 34 is performed using ultraviolet light, X-rays, electron beams, or the like. In addition, the resist film 3
The pattern No. 4 is as shown in FIG.
As shown in FIG. 10(b), there is a form with two such thin slits 35, or as shown in FIG. 10(c), there is a resist film 34 in the center. A configuration in which narrow slit-shaped exposed portions (35) are formed at both ends of the track portion in the width direction, leaving a portion of the width of the track portion, is preferably adopted.

In particular, the width of such a track portion is, for example, 50 mm. If the size is larger than un, the number of slits 35 should be at least 2.
It is desirable to arrange the slits in stripes at predetermined intervals.If the track width is large and the number of slits is small, if you try to etch the entire track width, it will result in etching in the depth direction. The amount increases,
The required thickness of the metal magnetic material becomes thicker, which becomes unproductive.

To solve this problem, increasing the slit width increases the
7. The slope of the etched ferrite surface with respect to the gap becomes smaller, and the effect of improving the contour effect becomes smaller.

Next, the ferrite block 31 on which the predetermined resist film 34 has been formed is subjected to a known electrolytic etching treatment or chemical etching treatment. As a result, the exposed surface of the track portion that is not covered with the resist film 34, in other words, the portion of the track portion corresponding to the slit 35 of the resist film 34 is etched through the slit 35, as shown in FIG. Thus, the surface of the track portion becomes an uneven surface 36. Note that the etching conditions are selected such that the etching ratio of the ferrite to the non-magnetic material 33 buried in the track width defining groove 32 is extremely large.

After this etching d, when the resist film 34 is removed, a track portion having an uneven surface 36 etched into a shape as shown in an enlarged view in FIG. 12 is exposed. Regarding the surface shape of this exposed track portion, the first
Figure 2 (a), (b).

(c) corresponds to the formation forms of resist@34 in Figs. 10 (a), (b), and (C), and in any of the forms, the resist is inclined with respect to the magnetic gap. The surface shape, in other words, is formed as a curved or bent surface forming part of a waveform in the width direction of the track portion.

As shown in FIG. 13, the etched ferrite block 31 is coated with a metal magnetic material 37 having a higher saturation magnetic flux density than the ferrite by sputtering or the like over the entire gear facing surface 31a. Dressed (fifth step). This metal magnetic material 37 includes Fe-3i (Si: 6.5% by weight), Fe-Aff
There are known crystalline alloys such as i-3i alloy (sendust) and N t Fe alloy (permalloy), while amorphous alloys such as Fe-co-3t
A well-known metal-metalloid alloy represented by -B series, a well-known metal-metal alloy such as Co-Zr, Co-Zr-Nb, etc. are used. In addition, other methods for depositing such magnetic materials include vacuum evaporation, ion blating, and CVD.
, plating, etc. are also possible, but sputtering is preferably employed because compositional fluctuations are large and the materials to be deposited are limited.

Note that, prior to the deposition of such metal magnetic material 37, the uneven surface 3 of at least the track portion of the ferrite block 31 is
6, a glass layer is placed as an intermediate layer, for example, several tens to ten
By depositing the metal magnetic material at a thickness of approximately zero, it is possible to further improve the adhesion of the layer of the metal magnetic material. The presence of this intermediate glass layer increases the playback output due to the simulated gap, and there is concern about the contour effect.
If the ferrite interface of the etched track portion is made sufficiently inclined with respect to the gap, this is not a serious problem.

Next, the ferrite block 31 with the metal magnetic material 37 adhered thereto is subjected to normal cutting and polishing operations on its gap-opposing surface 31a, so that the metal magnetic material 37 adhered to the ferrite block 31 is removed. Unnecessary parts, ferrite parts, and part of the non-magnetic material 33 are removed (
6th step). That is, by removing a predetermined thickness portion of the gap facing surface 31a of the ferrite block 31 to which the metal magnetic material 37 is adhered, the metal magnetic material 37 is formed on the uneven surface 36 of the track portion, as shown in FIG. The non-magnetic material 33 embedded in the track width defining groove 32 is exposed while leaving the adhered layer of the metal magnetic material 37 with a predetermined thickness, and the non-magnetic material 33 is made up of the remaining metal magnetic material layer and the ferrite portion. The width of the track section is defined.

Further, prior to or after the sixth step, a groove 38 for coil winding is formed in at least one of the two ferrite blocks 31, 31' on the side facing the gap 31a. Here, the first to sixth steps are applied only to one ferrite block 31, but the first to sixth steps are also applied to the other ferrite block 31'. There is no problem even if the ferrite blocks 31 and 31' are provided, and in particular, in the present invention, the first to sixth steps are advantageously applied to each of the two ferrite blocks 31 and 31'. After that, the gap facing surfaces (
31a) is given a final finish by surface polishing, resulting in a ferrite block 31.31' having a finished surface 39 facing the gear knob, as shown in FIG.

Then, a non-magnetic material for gap formation such as SiO2 or glass is applied to a predetermined thickness on the gap formation portion of at least one gap facing finished surface 39 (39') of the ferrite block 31, 31' obtained in the seventh step. A gap forming layer with a predetermined thickness is formed by sputtering (eighth step). At this time, a crystalline alloy such as Fe-3iSFe-Al-3i is used as the metal magnetic material 37. Si
It is desirable to use NG or high melting point glass as the non-magnetic material for forming the gap, and when Ni-Fe alloy or amorphous alloy is used as the metal magnetic material,
It is desirable to use a low melting point glass that can be bonded and heat treated at 400°C to 450°C as the nonmagnetic material for forming the gap.

Next, the two light blocks 31 and 31' obtained in the eighth step are aligned and opposed so that the finished surfaces 39 and 39' facing the gap are matched with each other, and an annular shape is formed. A magnetic path is formed, and by heating and pressurizing, they are joined and integrated in a conventional manner to form a ferrite block joined body 40 as a combination as shown in FIG. 16 (ninth step).
.

In this case, if the non-magnetic material 33 filled in the track width defining groove 32 is glass, the bonding is performed by bonding this glass to glass as the non-magnetic material for forming the gap.

Further, by cutting the ferrite block assembly (combined body) 40 joined in the ninth step so as to have the required core width (T) shown by the dotted line in FIG. 17 with the track width as the center. The target cores for the composite magnetic head are sequentially cut out, and at least one of the cores is thus obtained. Note that when cutting out the core, a well-known method of cutting the core at an angle of the azimuth angle may also be adopted, as the case may be.

The structure of the core for a composite magnetic head according to the present invention thus obtained is shown in a perspective view in FIG. This structure corresponds to the case shown in FIG. 5(a) in which the track width defining groove 32 is formed only in the ridge of the ferrite block 31 in the first step, and FIG. 19 shows the core for such a magnetic head. The configuration of the main part as seen from the surface facing the magnetic recording medium is shown. On the other hand, the structure of the magnetic head core shown in FIG. 20 corresponds to the case shown in FIG. It is. In these figures, 41 is a magnetic gap formed between the metal magnetic material layers 37 and 37' of the left and right track portions.

As is well known, the core for a composite magnetic head obtained according to the present invention is further wound with a coil using the hole 42 formed by the groove 38 for coil winding. Thus, the desired composite magnetic head is achieved.

The method for manufacturing a core for a magnetic head according to the present invention has been described in detail above based on an example of manufacturing a core for a magnetic head for a VTR. It should be understood that the invention is in no way intended to be different from the spirit of the invention, and that it can be implemented in forms with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, without departing from the spirit of the invention. be.

Furthermore, the method of manufacturing a core for a composite magnetic head according to the present invention is applicable not only to the exemplified VTR head but also to the manufacture of cores for magnetic heads such as FDD heads, RDD heads, and even DAT heads. Needless to say, it is also applicable.

(Effects of the Invention) As is clear from the above explanation, the method for manufacturing a core for a composite magnetic head according to the present invention has the following advantages: (a) In the core for a composite magnetic head obtained, the main magnetic circuit is is made of ferrite, and the metal magnetic material exists only near the magnetic gap, so this method can reduce eddy current loss. (b) The bonding interface between the ferrite and the metal magnetic material is magnetic. Due to the uneven structure that is diagonal to the gap, the contour effect can be ignored.
In addition, in order to improve adhesion, even if a glass layer is provided as an intermediate layer between the ferrite and the metal magnetic material, it has the advantage that such a contour effect can be ignored. (d) By combining lithography technology using resist and etching technology, it is possible to mass-produce magnetic head cores with highly accurate track widths by utilizing the etching speed ratio of the non-magnetic material buried in advance and the ferrite. , it is possible to simultaneously etch a large number of ferrite blocks into a uniform shape, and as a result, it is possible to mass produce magnetic head cores with uniform head characteristics; (e) after pouring a non-magnetic material into the track width defining groove in advance; Since it forms a magnetic film made of a metallic magnetic material, it is possible to use high-melting point glass, which has no problems such as wear resistance or chipping during processing.In particular, amorphous alloys and When permalloy alloy is used, there is no thermal deterioration, and when Sendust is used, there are no problems such as cranking or peeling in subsequent processing steps, making it suitable for industrial use in magnetic head cores. It has a number of great advantages, such as being able to be manufactured advantageously.

[Brief explanation of drawings]

1 and 2 are a perspective view and a top view, respectively, showing an example of a conventional composite magnetic head core, and FIG. 3 shows another example of a conventional composite magnetic head core. FIG. 4 is a perspective view, and FIGS. 4A and 4B are a perspective view and a top view, respectively, showing still another example of a conventional composite magnetic head core. 5 to 20 are explanatory diagrams of each process according to an embodiment of the present invention, and FIGS. 5(a) and 20(b) illustrate a ferrite block provided with different track width defining grooves, respectively. 6(a) and 6(b) are schematic cross-sectional views showing different cross-sectional forms of the track width defining groove, respectively. FIG. 7 is a perspective view of the main part of the ferrite block after the second step, and FIG. Fig. 8 is a perspective view of the ferrite block showing the state after the third step, Fig. 9 is a perspective view of the ferrite block showing the state in which the resist film is formed in the fourth step, and Figs. 1O (a) and (b). ) and (C) are perspective views of essential parts of ferrite blocks provided with resist films of different shapes, FIG. 11 is a perspective view of the ferrite block showing the state after etching in the fourth step, and FIG. 12 (a) ), (b), and (c) are perspective views of main parts showing different examples of the uneven surface forms of track portions formed based on different slit forms of resist films, and Fig. 13 is a diagram showing the implementation of the fifth step. FIG. 14 is a perspective view of the ferrite block subjected to the sixth step, FIG. 15 is a perspective view of the ferrite block subjected to the seventh step, and FIG. FIG. 17 is a perspective view of a combination body formed by integrating two ferrite blocks in the ninth process; FIG. 18 and 19 are a perspective view and a top view, respectively, showing an example of a composite magnetic head core obtained according to the process of the present invention, and FIG. 20 is a perspective view and a top view showing an example of a composite magnetic head core obtained according to the present invention. FIG. 18 is a diagram corresponding to FIG. 18 showing an example. 31.31': Ferrite block 31a: Gap facing surface 32.32':) Rack width defining groove 33.33': Non-magnetic embedding material 34 Ni resist film 35 Nislit 36: Uneven surface 37.37': Metal magnetic material 38: Three coil winding grooves: Gap opposing finished surface 40: Ferrite block assembly 41: Magnetic gap FIG. Figure 3 vK4 (a) Figure 5 Figure 6 (a) (b) Figure 13 Figure q Procedural amendment (voluntary) August 3, 1988 Patent application No. 142749 2, Invention (406) Nippon Insulators Co., Ltd. (4) Column 6 of the detailed description of the invention in the attorney's specification; Contents (1) On page 23, line 13 of the specification, insert the following sentence after "...is used." without starting a new line. Note: When using Fe-3t, Fe-Aj!-3t alloys, etc., as is well known, in order to improve corrosion resistance, etc., Cr, Ti, Ta, etc. (2) On page 24, line 4 of the same document, after "...is possible.", insert the following sentence (without a line break). , it is advantageous for adhesion if at least one element among Fe, Ni, Co, etc. is used as the intermediate layer.When these magnetic materials are used as the intermediate layer, the thickness is 100 mm.
It shall be less than oÅ. Furthermore, the existence of these intermediate layers increases the false gap and there is a concern about the contour effect, but this will not be a problem if the interface of the etched track section is made sufficiently inclined with respect to gear two. (3) In the 11th line of page 27, insert the following sentence without a line break. In other words, as a non-magnetic material for gap formation, S
To! , a high melting point oxide such as Al2O3 is formed on the surface facing the gap, and the coil winding groove is further formed as necessary.
It is also possible to join a pair of ferrite blocks by inserting glass rods into the rear grooves and applying heat and pressure to melt the glass rods inserted into these grooves. As for the glass that is inserted into this groove and melted, the bonding temperature will be selected depending on the type of metal magnetic material, as described above. "that's all

Claims (3)

[Claims] (1) A core for a magnetic head using a combination body in which first and second ferrite blocks are butted against each other to form an annular magnetic path, and a magnetic gap of a predetermined distance is formed at the butted portion of the ferrite blocks. In the manufacturing method, at least two grooves parallel to each other and defining a track width are formed in at least a magnetic gap forming region of an abutting surface of at least one of the two ferrite blocks with respect to the other ferrite block. a first step of forming the magnetic gap in a direction perpendicular to the magnetic gap; and applying a predetermined non-magnetic material to the abutting surfaces of the ferrite blocks in which the track width defining groove is formed, thereby forming a magnetic gap in the track width defining groove. a second step of embedding the non-magnetic material in the ferrite block; and a third step of removing unnecessary portions of the non-magnetic material applied to the abutting surfaces of the ferrite blocks to expose the track portions sandwiched between the track width defining grooves. and after forming a predetermined resist film on the abutting surfaces of the ferrite blocks so that a part of the track portion is exposed as at least one exposed portion extending in the forming direction of the track width defining groove with a predetermined width. a fourth step of etching the track portion through the exposed portion to form an uneven surface; a fifth step of depositing a predetermined metal magnetic material on the etched abutment surface of the ferrite block; A predetermined thickness portion of the abutting surface of the ferrite block to which the metal magnetic material is adhered is removed, and the adhesion layer of the metal magnetic material formed on the uneven surface of the track portion is left at a predetermined thickness. a sixth step of exposing the non-magnetic material buried in the track width defining groove; and prior to or after the sixth step, the abutting surface of at least one of the first and second ferrite blocks; a seventh step of forming a groove for coil winding; and at least a magnetic gap forming region of the abutting surface of at least one of the first and second ferrite blocks after the first to seventh steps have been completed; An eighth step of forming a non-magnetic layer with a predetermined thickness; and the first and second ferrite blocks that have completed the eighth step, with their magnetic gap forming portions on the abutting surfaces facing each other and joined to each other to be integrated. a ninth step; and a tenth step of cutting the joined and integrated first and second ferrite block combination at a predetermined position to obtain at least one composite magnetic head core. A method for manufacturing a core for a composite magnetic head characterized by: (2) in the fourth step, a plurality of the exposed portions are formed on the track portion at predetermined intervals;
Claim 1, wherein the track portion is etched through the plurality of exposed portions, thereby forming a curved or bent surface that forms part of a waveform in the width direction of the track portion. Manufacturing method. (3) Prior to the fifth step, the ferrite constituting the track portion and the metal magnetic material deposited thereon are coated on at least the surface of the exposed track portion of the abutting surface of the ferrite block. The manufacturing method according to claim 1 or 2, wherein a glass layer that is brought into close contact is formed.