JPH06101093B2 - Manufacturing method of core for composite type magnetic head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a core for a composite magnetic head, and more particularly to a magnetic head suitable for recording / reproducing a high frequency signal such as a VTR,
In particular, the present invention relates to a method for advantageously manufacturing a composite magnetic head core that provides a composite magnetic head suitable for a high coercive force medium.

(Background Art) In a high-density magnetic recording / reproducing apparatus, it is known that it is advantageous to increase the coercive force: H _C of the magnetic recording medium, but in order to record information on the magnetic recording medium having a high coercive force. Needs to increase the leakage magnetic field from the magnetic head.
However, the ferrite material currently used for the core of the magnetic head has a saturation magnetic flux density: B _S of 4000 to
Since it is 5000 gauss, there is a limit to the strength of the recording magnetic field that can be obtained, and when the coercive force of the magnetic recording medium exceeds 1000 Oersted, there is a drawback that the recording becomes insufficient.

On the other hand, crystalline alloys such as Fe-Al-Si alloys (Sendust) and Ni-Fe alloys (Permalloy), which are collectively referred to as metallic magnetic materials,
Alternatively, a magnetic head using an amorphous alloy generally has excellent characteristics such as a higher saturation magnetic flux density and a lower sliding noise than a ferrite material. However, in a commonly used track width (10 μm or more), the effective magnetic permeability in the video frequency region is lower than that of ferrite due to the eddy current loss, and the reproduction efficiency is lowered. Also, it is several steps inferior to ferrite in terms of wear resistance.

Therefore, in order to solve the above problems, a core for a composite magnetic head has been proposed in which ferrite and a metal magnetic material are combined and the advantages of both are utilized.

For example, as shown in FIG. 1 which is a perspective view of one of the cores for such a composite type magnetic head, the core portions 1, 1 ′ are made of ferrite having a high magnetic permeability, and the main portion of the recording action. There has been proposed a core for a composite type magnetic head having a structure in which a magnetic gap 5 near the magnetic gap 5 is formed of a metal magnetic material 2, 2'formed by physical vapor deposition such as sputtering. In this magnetic head core, for high-density recording, the track width is narrowed, and notch grooves 7, 7 for narrowing the track width are provided on both sides in the vicinity of the magnetic gap 5, and a nonmagnetic material for reinforcement is provided there. 3 is filled. In addition, 6 is a window (hole) for coil winding. FIG. 2 shows a plan view of the recording medium facing surface of such a conventional magnetic head core, in which the coupling boundary portion between the ferrite core portion 1,1 ′ and the metallic magnetic material 2,2 ′ is shown. It is recognized that 4,4 'acts as a pseudo gap and impairs the recording / reproducing characteristics. In particular, when the coupling boundaries 4 and 4'and the magnetic gap 5 are parallel to each other, a considerable amount of signals are picked up at the boundaries, and the so-called contour effect becomes severe, which causes undulations in the frequency characteristics of the reproduction output. Is inherent.

By the way, the cause of this contour effect is considered as follows. That is, the head core having the above structure is generally manufactured by the following steps. First, a metal magnetic material is applied to the mirror-finished gap facing surface of the ferrite block, and then a track width defining groove is formed, and a nonmagnetic material, generally glass, is embedded in the track width defining groove. After that, it is a process of performing gap junction. However, in such a manufacturing method, since the non-magnetic material (glass) is poured after forming the magnetic layer made of a metal magnetic material, in order to use reliable glass, the pouring temperature is 650 ° C or higher. Therefore, a diffusion reaction occurs at the interface between the ferrite and the metal magnetic layer, and a nonmagnetic layer is likely to occur. Then, the nonmagnetic layer at this interface acts as a pseudo gap, and the contour effect appears. In addition, when the track width defining groove is formed, the metal magnetic layer is cut by a grindstone, so that the grindstone wear is larger than that of ferrite and the metal magnetic layer is easily peeled off.

On the other hand, in the case of the core shape shown in FIG. 3, since the metal magnetic film is formed after the track width defining groove is formed, abrasion of the grindstone and peeling of the metal magnetic film are unlikely to occur, but the track width defining groove is formed after the metal magnetic film is formed. Since non-magnetic material (glass) is poured into the
Similar to the head core having the structure as shown in FIG. 1, a diffusion reaction layer is generated at the interface, which easily acts as a pseudo gap. Also,
This has the drawback that the thickness accuracy of the metal magnetic film affects the track width.

Further, JP-A-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 has a saturation magnetic flux higher than that of ferrite on at least both sides of the protrusions of the two high magnetic permeability ferrite blocks 21, 21 'having protrusions whose cross-sectional shape on the surface facing the magnetic recording medium protrudes. The magnetic bodies 22, 22 'having a high density are deposited, the magnetic bodies 22, 22' face each other through the magnetic gap 23 at the tip of the protrusion, and the width of the ferrite at the tip of the protrusion. Is smaller than the track width. Note that 2
Reference numerals 5 and 26 denote a nonmagnetic embedding material and a coil winding window, respectively.

In the case of such a structure, the boundary coupling portions 24 and 4'of the ferrites 21 and 21 'and the metal magnetic materials 22 and 22' are connected to the magnetic gap 2
Since it is greatly inclined with respect to 3, there is an advantage that there is no contour effect of reproduction output as in the magnetic head core as shown in FIG. 1, but the strength of the protrusion of the ferrite block is weak and the desired shape is obtained. In addition, it is difficult to obtain the track width, and the track width easily changes depending on the polishing amount of the surface where the magnetic gap 23 is formed. Therefore, it is difficult to obtain the accuracy of the track width.

In addition, JP-A-61-265714 and JP-A-61-2737 are also used.
In the publication No. 06, etc., as a core for a composite magnetic head made by combining ferrite and a magnetic metal material, an uneven portion is provided at the joint between the ferrite and the magnetic material, and the position of the uneven portion on the left and right core portions is set. Have been laid out in an asymmetrical position, or at least one minute gap extending toward the magnetic gap portion has been formed in the magnetic material. , Manufactured as follows.

That is, a predetermined ferrite block is provided with a resist film formed by forming slits in stripes, and etching is performed to form a corrugated uneven surface, and then a corrugated uneven surface is formed. After forming a magnetic layer made of a metallic magnetic material and polishing the surface to a flat surface, a plurality of grooves defining the track width were formed in parallel with each other, and then a groove for coil winding was formed. After that, the two ferrite blocks are combined and joined together to form an integral combination, and then this ferrite block combination is cut at a predetermined position to obtain the desired core for the composite magnetic head. A manufacturing method that sequentially cuts out is clarified.

However, in such a method of manufacturing a core for a composite type magnetic head, a non-magnetic material (glass) is poured into the track width defining groove after the formation of the magnetic layer made of a metal magnetic material. There is a problem like this. That is, when the metal magnetic material is an amorphous alloy or a permalloy alloy, such a magnetic material is 500 ° C.
If heated above, its magnetic properties deteriorate, and especially in the case of amorphous alloys, it will be greatly deteriorated due to crystallization, so glass must be poured into the track width defining groove at 500 ° C or less. , Therefore low melting glass must be used. Thus, in the case of a low melting point glass, not only is there a difficulty in abrasion resistance when the magnetic recording medium is slid, but it is also weak in strength and has a drawback in that chips such as grinding and cutting occur. .

Further, when the metal magnetic material is sendust, there is no problem that the magnetic characteristics are deteriorated by pouring the high melting point glass as described above, but it is 500 ° C. or higher, for example, 700
When heated above 800 ℃, the difference in thermal expansion coefficient with ferrite is large (Sendust: 150 × 10 ^-7 , Ferrite: 110
~ 120 × 10 ^-7 ), the internal stress of Sendust becomes large during glass fusion, and the material itself of Sendust is not sticky and is fragile and adheres to the corrugated surface of ferrite. This causes problems such as cracking or easy peeling during grinding and cutting.

In any case, the method for manufacturing the composite magnetic head core according to the method of pouring the nonmagnetic material (glass) into the track width defining groove after forming the magnetic film made of the metal magnetic material is practically used. However, there are some drawbacks, and it was not industrially advantageous.

Further, in Japanese Patent Laid-Open No. 61-242307, after a track glass is embedded in a track width regulating groove, a groove corresponding to the track width is formed between the track width regulating grooves (track grooving). ), A method of manufacturing a core for a composite magnetic head, which comprises forming a layer of an amorphous magnetic material, has been clarified. However, there is no specific disclosure regarding the track grooving method. Not
Therefore, there are still problems to be solved before putting such a method into practical use. For example, if such track grooving is performed using a grindstone, the track width will vary depending on the position accuracy and the cutting depth of the grindstone, and there is an inherent problem of lack of mass productivity. Of.

(Object of the Invention) Here, the present invention has been made in view of the above circumstances, and an object of the present invention is to solve the problems in the conventional core for a composite type magnetic head and the manufacturing method thereof. The present invention provides a core for a magnetic head that exhibits excellent recording / reproducing characteristics even for a high coercive force recording medium, and an easy manufacturing method therefor. In particular, it is easy to improve track width accuracy, and only ferrite is provided by an etching technique. Is preferentially etched to make the coupling interface between the ferrite and the metal magnetic material substantially parallel to the magnetic gap, while advantageously manufacturing a core for a composite magnetic head with less contour effect in reproduction output.

(Structure of the Invention) In order to achieve such an object, the present invention forms an annular magnetic path by abutting the first and second ferrite blocks, and at the abutting portions of the ferrite blocks, a predetermined gap is formed. In a method of manufacturing a core for a magnetic head using a combination body having a magnetic gap, (a) a track is formed on at least a magnetic gap forming portion of a butting 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 defining a width in a direction parallel to the abutting surface and orthogonal to the magnetic gap; and (b) forming the track width defining groove. Apply a predetermined non-magnetic material to the abutting surface of the ferrite block, and embed the non-magnetic material in the track width defining groove. A second step of: (c) a third step of removing an unnecessary portion of the non-magnetic material applied to the abutting surface of the ferrite block to expose the track portion sandwiched by the track width defining groove; d) After forming a predetermined resist film on the abutting surface of the ferrite block so that at least a portion of the exposed track portion located at the magnetic gap forming portion remains as an exposed portion, the exposed portion of the track portion is removed. A fourth step of chemically etching with phosphoric acid to form a recess having a predetermined depth in the exposed portion, and (e) a fifth step of depositing a predetermined metal magnetic material on the etched abutting surface of the ferrite block. And (f) removing a predetermined thickness portion of the abutting surface of the ferrite block coated with the metal magnetic material, and depositing the metal magnetic material deposited layer formed on the recess of the track portion. While leaving at is, the sixth step allowed to expose a non-magnetic material which is embedded in the track width defining grooves, after or said sixth step prior to (g) said sixth step,
A seventh step of forming a groove for coil winding on the abutting surface of at least one of the first and second ferrite blocks; and (h) the first and second steps completed from the first to seventh steps. An eighth step of forming a non-magnetic layer having a predetermined thickness on at least a magnetic gap forming portion of the abutting surface of at least one of the ferrite blocks of (1), and (i) first and second ferrites which have completed the eighth step. A ninth step in which the magnetic gap forming portions of the abutting surfaces of the blocks are opposed to each other and bonded to each other, and (j) such a bonded and integrated first and second ferrite block combination body is placed at a predetermined position. And a tenth step of obtaining at least one core for a composite magnetic head to cut the composite magnetic head core.

(Specific Configurations and Examples of the Invention) In the present invention, the first and second ferrite blocks that provide the combination used to manufacture the intended core for the composite magnetic head have been conventionally used. A ferrite material having a high magnetic permeability is used, and generally, it is used as a long plate-shaped block having a predetermined thickness so that a plurality of magnetic head cores can be manufactured, and the abutting thereof forms an annular magnetic path. It is confused. As for this high permeability ferrite block, Mn-
A single crystal or a polycrystal of Zn ferrite, Ni-Zn ferrite or the like or a composite thereof is used. In particular, when the single crystal is used, (100), (110),
Crystal planes such as (311) and (332) are advantageously selected as the gap facing surface (ferrite block butt surface).

And in the present invention, first, in the first step,
At least two grooves which are parallel to each other and define a track width in at least a magnetic gap forming portion of the abutting surface of at least one of the two ferrite blocks with respect to the other ferrite block are parallel to the abutting surface and have a magnetic gap. Will be 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 portion on a gap facing surface (butting surface) 31a of a predetermined high magnetic permeability ferrite block 31. The track width defining groove is formed in the ferrite block 31 as shown in FIG. 5 (a).
Is formed only on the ridge (magnetic gap formation site) of
As shown in FIG. 5 (b), the groove 3 is formed through the rear part of the core (the part opposite to the magnetic recording medium facing surface 31b).
Even if it is 2 ', it does not matter. The groove shapes of the track width defining grooves 32, 32 'are appropriately selected and provided, for example, in the shape as shown in FIGS. 6A and 6B. 6B has a shape in which the fluctuation of the track width is small even if the amount of polishing is large, that is, a groove shape as shown in FIG. 6A having a straight portion perpendicular to the gap facing surface 31a. It is more suitable than the groove shape.

In this way, in the ferrite block 31 provided with the track width defining groove 32, as shown in FIG. 7, in a second step, the gap facing surface 31a having the track width defining groove 32 is formed. A predetermined non-magnetic material 33 is applied on top of the non-magnetic material, and the non-magnetic material 33 is also provided in the track width defining groove 32.
33 will be buried and filled. As the non-magnetic material 33, glass, a ceramic-based inorganic adhesive, a hard resin, or the like is used, but glass is suitable in terms of stability such as running property of the magnetic recording medium.

Then, after the nonmagnetic material 33 is embedded in the track width defining groove 32 in this manner, at least the unnecessary nonmagnetic material 33 portion on the gap forming surface 31a of the ferrite block 31 is removed to define the track width defining area. The track portion sandwiched by the grooves 32, 32 is exposed (third step). To remove the unnecessary portion of the non-magnetic material 33, generally, a method of grinding and removing with a grindstone is adopted, and by such a removing operation, a predetermined thickness portion of the gap facing surface 31a of the ferrite block 31 is removed. . Then, by such a removing operation, as shown in FIG. 8, a ferrite block 31 in which the non-magnetic material 33 is embedded only in the track width defining groove 32 is obtained.

In the fourth step, with respect to the ferrite block 31 in which a predetermined nonmagnetic material 33 is embedded in the track width defining groove 32, the gap facing surface 31a where the track portion is exposed is formed.
Then, as shown in FIGS. 9 and 10, a predetermined resist film 34 is formed leaving at least the recording medium sliding portion side (magnetic gap forming portion) of the gap facing surface 31a. That is, the resist film 34 is formed on the gap facing surface 31a of the ferrite block 31 so that at least a portion of the exposed track portion located at the magnetic gap forming portion remains as an exposed portion.

Next, the ferrite block 31 on which the predetermined resist film 34 is formed is subjected to a chemical etching process using phosphoric acid, whereby a non-magnetic material 33 such as glass embedded in the track width defining groove 32 is formed. While avoiding the etching of, the exposed portion of the track portion not covered with the resist film 34 is removed as shown in FIGS. 11 and 12,
A recess having a predetermined depth having a width corresponding to the width of the track portion is formed. The chemical etching conditions are non-magnetic material embedded in the track width defining groove 32.
The condition that the etching ratio of ferrite to 33 is extremely large will be selected. Further, such chemical etching is generally carried out using an aqueous phosphoric acid solution, and for example, the liquid specific gravity is 1.60 to 1.70, the liquid temperature is 40 to 150 ° C.
It is carried out under a certain condition. As the glass that is a non-magnetic material for embedding the track width defining groove 32,
With the glass of the PbO-SiO ₂ system, the etching ratio of the glass to ferrite becomes 1/100 or less, not affect the track width accuracy. Then, after this etching, when the resist film 34 is removed, the shape as shown in FIG.
The track portion in which a recess having a predetermined depth is etched in a substantially parallel shape is exposed.

Then, as shown in FIG. 13, the ferrite block 31 subjected to the etching treatment is covered with a metal magnetic material 37 having a saturation magnetic flux density higher than that of ferrite by sputtering or the like on the entire surface 31a facing the gap. Dressed up (fifth step). This metallic magnetic material 37 contains Fe-Si
(Si: 6.5% by weight), Fe-Al-Si alloy (Sendust), Ni
There are known crystalline alloys represented by -Fe alloy (permalloy) and the like, while amorphous alloys such as Fe-Co-Si are also available.
-Well-known metal-metalloid alloys represented by B system,
Well-known metal-metal alloys such as Co-Zr and Co-Zr-Nb are used. In addition, when using Fe-Si, Fe-Si-Al based alloys, in order to improve the corrosion resistance, 5% by weight or less of Cr, T
Elements such as i and Ta are added as appropriate. Further, in addition to such deposition of the magnetic material, vacuum deposition, ion plating, CVD, plating and the like are also possible, but due to large composition fluctuations and the deposition material is limited, A sputtering method is preferably adopted.

Prior to the deposition of such a metal magnetic material 37, at least the track surface of the ferrite block 31 is etched.
A glass layer, for example, several tens to 100 as an intermediate layer on
It is possible to further improve the adhesiveness of such a layer of the metal magnetic material by applying it at a thickness of about Å. Also, if the thickness of this intermediate glass layer is 100 Å or less, the action as a pseudo gap is small and there is no practical problem, and at least one element of Fe, Ni, Co, etc. is used for the intermediate layer. If so, it will be advantageous in terms of adhesion. Further, in the case of these magnetic materials, if it is 1000 Å or less, the action as a pseudo gap is small and it does not pose a problem in practical use.

Next, the ferrite block 31 to which the metal magnetic material 37 is adhered is subjected to usual cutting and polishing operations on the gap facing surface 31a, and the ferrite block 31 is
The unnecessary portion of the metallic magnetic material 37, the ferrite portion and a part of the non-magnetic material 33 adhered to 31 are removed (sixth step).
That is, by removing a portion of the predetermined thickness of the gap facing surface 31a of the ferrite block 31 to which the metal magnetic material 37 is deposited, as shown in FIG. 14, it is formed on the etched surface 36 of the track portion. The nonmagnetic material 33 buried 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 remaining magnetic metal material layer and the ferrite portion are formed. The width of the track portion to be specified will be specified.

In addition, prior to or after the sixth step, at least one of the two ferrite blocks 31 and 31 'is provided on the gap facing surface 31a side thereof with a groove 38 for coil winding, and if necessary. As a result, a groove for filling the reinforcing glass is formed in the rear part. Here, the first to sixth steps are applied only to one ferrite block 31, but the other ferrite block 31 is also applied.
Even if 31 ′ is similarly provided with the first to sixth steps, it does not matter at all, and particularly in the present invention,
The above first to sixth steps are advantageously applied to the two ferrite blocks 31 and 31 ', respectively. Then, after that, the gap facing surfaces (31a) of the ferrite blocks 31, 31 'which are abutted against each other are surface-polished to be finally finished, and as shown in FIG. Ferrite blocks 31, 31 'having

And the ferrite block obtained in the seventh step
At least one of 31,31 'gap facing surface 39 (3
A non-magnetic material for forming a gap such as SiO ₂ or glass is applied to the gap forming portion of 9 ′) by sputtering to a predetermined thickness to form a gap forming layer having a predetermined thickness (eighth step). .

Then, the two ferrite blocks 31, 31 ′ obtained in the eighth step are treated with respective gap facing finish surfaces 39,
By aligning and facing 39 'so that the respective track parts match, an annular magnetic path is formed, and by inserting a glass rod into the coil winding groove and, if necessary, the rear groove, heating and pressing , The glass put in these grooves is melted and the ferrite blocks 31, 31 'are joined. For example,
It uses glass with a softening point of 360 ° C and is joined at 500 ° C.

In addition, the ferrite block bonded body (combined body) 40 bonded in the ninth process is
By cutting the core so that it has a required core width (T) indicated by a dotted line in the drawing, the target composite magnetic head core is sequentially cut out, and at least one of the cores is obtained. Incidentally, when cutting out the core, a method of tilting by an azimuth angle and cutting the core may be used depending on the case.

The structure of the composite type magnetic head core according to the present invention thus obtained is shown in FIG. 18 as a perspective view. This structure corresponds to the case of FIG. 5 (a) in which the track width defining groove 32 is formed only on the ridge portion of the ferrite block 31 in the first step, and FIG. 19 shows such a core for a magnetic head. The morphology of the main part as viewed from the surface facing the magnetic recording medium is shown. On the other hand, the structure of the magnetic head core shown in FIG.
The structure corresponds to the case of FIG. 5B in which the track width defining groove 32 'is formed up to the rear portion. 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.

In this way, the core of the composite magnetic head obtained according to the present invention is wound with a coil by utilizing the hole 42 formed by the groove 38 for coil winding, as is well known. Thus, the desired composite magnetic head is obtained.

The method for manufacturing the magnetic head core according to the present invention has been described in detail above based on the manufacturing example of the VTR magnetic head core, but the present invention is construed as being limited to only the specific examples. It should be understood that the present invention is not limited to the above, and may be implemented in a form in which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention. is there.

Further, the manufacturing method of the composite magnetic head core according to the present invention is not limited to just the exemplified VTR head, and the FDD head,
Needless to say, the present invention can be applied to the manufacture of cores for magnetic heads such as RDD heads and even DAT heads.

(Effects of the Invention) As is clear from the above description, the manufacturing method of the core for a composite magnetic head according to the present invention is (a) in the obtained core for a composite magnetic head, as compared with the conventional one, in the main magnetic circuit. Is composed of ferrite and the magnetic metal material exists only in the vicinity of the magnetic gap, which is a method that can reduce eddy current loss. (B) After the glass is embedded in the track width defining groove, the metal Since a highly reliable track glass can be used to form a magnetic material, and the gap junction can be formed at a low temperature, the diffusion reaction layer of the metal magnetic material and ferrite can be thinned, and the pseudo gap effect, That is, the contour effect can be reduced, and since the ferrite surface in contact with the metal magnetic layer is an etched surface, there is no deterioration in magnetic characteristics, and pseudo It also has the advantage that it does not contribute to the gap. (C) By eliminating the need to form a groove for burying a metallic magnetic material, and also for a non-magnetic pre-embedded groove for defining the track width. It is possible to mass-produce magnetic head cores with a highly accurate track width by using the ratio of the etching rate of the material and ferrite. (D) A large number of ferrite blocks can be obtained by combining the lithography technology using a resist and the etching technology. Can be simultaneously etched into a uniform shape, and thus a magnetic head core with uniform head characteristics can be mass-produced. (E) A non-magnetic material is poured into the track width defining groove in advance, and then a magnetic metal material is removed. Since it forms a magnetic film, it is free from problems such as wear resistance and chipping during processing.
High melting point glass can be used, especially when using amorphous alloy or permalloy alloy as the metal magnetic material, there is no thermal deterioration, while when sendust is used, cracks occur in the subsequent processing steps. Since there is no problem such as peeling, industrial production of the magnetic head core can be advantageously carried out, and there are a number of great advantages.

[Brief description of drawings]

1 and 2 are a perspective view and a top view showing an example of a conventional composite type magnetic head core, respectively, and FIG. 3 shows another example of a conventional composite type magnetic head core. Second
It is a figure equivalent to a figure, and Drawing 4 (a) and (b) is a perspective view and a top view showing other examples of the conventional core for compound type magnetic heads, respectively. 5 to 20 are explanatory views of each step according to one embodiment of the present invention, and FIGS. 5 (a) and 5 (b) show a ferrite block provided with different track width defining grooves, respectively. 6A and 6B are schematic cross-sectional views showing different cross-sectional shapes of the track width defining groove, and FIG. 7 is a perspective view of a main part of the ferrite block after completion of the second step. FIG. 8 is a perspective view of the ferrite block showing a state where the third step is completed, FIG. 9 is a perspective view of the ferrite block showing a state where the resist film is formed in the fourth step, and FIG. 10 is a perspective view of FIG. An enlarged explanatory view of a main part of a ferrite block provided with a resist film, FIG. 11 is a perspective view of a ferrite block showing a state after etching in a fourth step, FIG. 12 is an enlarged explanatory view of a main part in FIG. 11, Thirteenth
Figure is a cross-sectional explanatory view of the main parts of the ferrite block subjected to the fifth step, Figure 14 is a perspective view of the ferrite block subjected to the sixth step, and Figure 15 is a perspective view of the ferrite block subjected to the seventh step. Fig. 16 is a perspective view of a combination body in which two ferrite blocks are integrated in the ninth step, and Fig. 17 shows a cutting position for obtaining one composite magnetic head core in the tenth step. 18 and 19 are perspective views and top views, respectively, showing an example of a composite magnetic head core obtained by the process of the present invention, and FIG. 20 is obtained by the present invention. FIG. 19 is a diagram corresponding to FIG. 18 showing another example of the core for the composite magnetic head. 31, 31 ': Ferrite block 31a: Gap facing surface 32, 32': Track width defining groove 33, 33 ': Non-magnetic embedding material 34: Resist film, 36: Etched surface 37, 37': Metal magnetic material 38: Coil Winding groove 39: Gap facing finished surface 40: Ferrite block bonded body 41: Magnetic gap

Claims (1)

[Claims] 1. A magnetic head using a combination body in which a first and a second ferrite block are butted against each other to form an annular magnetic path, and a magnetic gap having a predetermined gap is formed at the butted portion of these ferrite blocks. In the method for manufacturing a core for use, at least two grooves parallel to each other that define a track width are provided in the abutting surface at least at a magnetic gap forming portion of the abutting surface of at least one of the two ferrite blocks with respect to the other ferrite block. The first step of forming in the parallel direction and in the direction orthogonal to the magnetic gap, and applying a predetermined non-magnetic material to the abutting surface of the ferrite block in which the track width defining groove is formed, thereby defining the track width The second step of embedding the non-magnetic material in the groove, and the non-magnetic material applied to the abutting surface of the ferrite block. The third step of removing unnecessary portions of the conductive material to expose the track portion sandwiched by the track width defining grooves, and at least the portion of the exposed track portion located at the magnetic gap forming site is the exposed portion. To remain
After forming a predetermined resist film on the abutting surface of the ferrite block, a fourth step of chemically etching the exposed portion of the track portion with phosphoric acid to form a recess having a predetermined depth, A fifth step of depositing a predetermined metal magnetic material on the etched abutting surface of the ferrite block, and removing a predetermined thickness portion of the abutment surface of the ferrite block coated with the metal magnetic material, and removing the track portion of the track portion. A sixth step of exposing the non-magnetic material embedded in the track width defining groove while leaving the adhered layer of the metal magnetic material formed on the recess with a predetermined thickness, and prior to the sixth step. Or after the sixth step, a seventh step of forming a groove for coil winding on the abutting surface of at least one of the first and second ferrite blocks, and the end of the first to seventh steps First and foremost And a second ferrite block, an eighth step of forming a nonmagnetic layer having a predetermined thickness on at least a magnetic gap forming portion of the abutting surfaces of the first and second ferrite blocks, and the first and second ferrites having completed the eighth step. The ninth step in which the magnetic gap forming portions of the abutting surfaces of the blocks are opposed to each other and are joined to each other and integrated, and the first and second ferrite block combination bodies thus joined and integrated are cut at a predetermined position. And a tenth step of obtaining at least one core for a composite magnetic head.