JPS62125509A - Magnetic head - Google Patents

Abstract

PURPOSE:To effectively utilize the high saturation magnetic flux density characteristic by abutting magnetic core halves on each other while shifting the halves from each other so that a ferromagnetic oxide is not confronted with a ferromagnetic thin film on a magnetic gap forming surface. CONSTITUTION:The magnetic core halves I and II are composed of magnetic core parts 11 and 12 each consisting of a ferromagnetic oxide and ferromagnetic metallic thin films 13A and 13B formed on the ferromagnetic thin film forming the surfaces of the core parts 11 and 12 by a vacuum thin film forming technique. The magnetic gap is formed by abutting the magnetic thin films 13A and 13B on each other, the ferromagnetic thin film forming surfaces and a magnetic gap forming surface 10 are inclined to a specified angle on the magnetic recording medium facing surface, and the abutted ferromagnetic metallic thin films 13A and 13B are connected almost in a straight line. Meanwhile, the ferromagnetic metallic thin films 13A and 13B of one magnetic core halves I and II and the ferromagnetic oxide of the other magnetic core halves I and II are not confronted with one another on the magnetic gap forming surface 10. By such a structure, the optical track width and the effective track width in recording or the effective track width in reproduction are almost equalized, and the high saturation magnetic flux density characteristic of the ferromagnetic metallic thin film can be effectively utilized.

Description

[Detailed description of the invention] The present invention will be explained in the following order.

A. Industrial application field Summary of B9 invention C0 conventional technology Problems that the invention attempts to solve Measures to solve E3 problems F0 action G. Example G-■ Explanation of magnetic head G-■ Effective track width measurement results G-■ Manufacturing process.

H0 Effects of the Invention A, Industrial Field of Application The present invention relates to a magnetic head, and particularly to a so-called composite magnetic head in which a portion near a magnetic gap is formed of a ferromagnetic metal thin film.

B0 Summary of the Invention The present invention provides a magnetic core half pair composed of a magnetic core portion made of a ferromagnetic oxide and a ferromagnetic metal thin film formed by a vacuum thin film formation technique on the ferromagnetic thin film forming surface of the magnetic core portion. A magnetic gap is formed by abutting the ferromagnetic metal thin films, and the ferromagnetic thin film forming surface and the magnetic gap forming surface are inclined at a predetermined angle on the surface facing the magnetic recording medium, and the abutted magnetic In a magnetic henode made up of magnetic metal thin films connected in a substantially straight line, the ferromagnetic metal thin film of one half-pair of magnetic cores butts against the ferromagnetic oxide of the other half-pair of magnetic cores so that they do not face each other on the magnetic gap forming surface. By doing so, the present invention aims to provide a magnetic head that can substantially equalize the effective gap length during recording and reproducing, and make effective use of the excellent magnetic properties (for example, high saturation magnetic flux density, etc.) of the ferromagnetic metal '1npI3. That is.

C1 Conventional technology For example, in magnetic recording and reproducing devices such as VTRs (video tape recorders), the density of recording signals is increasing, and in response to this high density recording, magnetic powder such as Fe and Co is being used as magnetic recording media. , using powder of ferromagnetic metal such as Ni,
So-called metal tapes and so-called vapor-deposited tapes in which a ferromagnetic metal material is deposited on a heather film by vapor deposition have come into use. Since this type of magnetic recording medium has a high coercive force Hc, the head material of the magnetic head used for recording and reproduction also has a high saturation magnetic flux density Bs.
It is required to have the following. For example, ferrite materials, which are conventionally widely used as magnetic head materials, have a low saturation magnetic flux density Bs, and permalloy has problems in wear resistance.

On the other hand, with the above-mentioned high-density recording, the recording trunk recorded on a magnetic recording medium is also becoming narrower, and accordingly, the track width of the magnetic head is also required to be extremely narrow.

Therefore, conventionally, a ferromagnetic metal 'III film with high saturation magnetic flux density is deposited on a non-magnetic substrate such as ceramic or glass.
A composite magnetic head has been proposed that uses this as a trunk part, but in this type of magnetic head, the magnetic path is composed only of a thin ferromagnetic metal thin film, so the magnetic resistance is large, which is undesirable in terms of efficiency. Furthermore, since the film of the ferromagnetic metal FI@ is formed using a vacuum thin film forming technique with an extremely slow film growth rate, there are problems such as the time required to produce the magnetic head.

Alternatively, a composite magnetic head has been proposed in which the magnetic core portion is made of a ferromagnetic oxide such as ferrite, and a ferromagnetic metal thin film is coated on the magnetic gap forming surface of each magnetic core portion. Since the magnetic path and the metal thin film are located in a direction perpendicular to each other, eddy current loss may occur, leading to a decrease in the reproduction output, and a pseudo gap may be formed between the magnetic core portion and the metal thin film, making it difficult to There are problems such as not being able to obtain sufficient reliability.

Therefore, the applicant of the present application previously proposed in Japanese Patent Application No. 58-250988 a composite magnetic head suitable for high-density recording on 6-1 tape having high coercive force such as metal tape. . As shown in FIG. 15, this magnetic head includes a pair of magnetic core portions (101) formed of a ferromagnetic oxide such as Mn-Zn ferrite;
The abutting surfaces of (102) are cut diagonally, respectively, to form ferromagnetic metal thin film forming surfaces (103) and (104), and this ferromagnetic metal thin film forming surface (103).

(104) Fe-Af-3 was formed using vacuum thin film formation technology on (104).
Ferromagnetic metals such as i-based alloys (so-called sendust)
Films (105) and (106) are formed by depositing these ferromagnetic metals mIl! (105) and (106) are brought into contact to form a magnetic gap (107), and a tape sliding contact surface is secured within the trunk width regulating groove to form a ferromagnetic metal thin film (105).

(106) low melting point glass (10
8).

(109) or high melting point glass (110), (11
1), and has excellent characteristics in terms of reliability, magnetic properties, wear resistance, etc.

D0 Problems to be Solved by the Invention Incidentally, in a magnetic head configured as described above, track width regulating grooves (101a), (102
When the cutting position in a) is slightly shifted, a magnetic core portion (101) made of ferromagnetic oxide is formed on the magnetic gap forming surface.
A part of (102) may remain. If the ferromagnetic oxide remains on the magnetic gap forming surface in this way, depending on how the left and right magnetic core half pairs are butted together, the ferromagnetic oxide of one magnetic core half pair and the other magnetic core half pair may form on the magnetic gap forming surface. A case may occur in which the ferromagnetic metal thin film of the magnetic core half pair faces each other.

In this configuration in which the ferromagnetic oxide and the ferromagnetic metal thin film face each other, the opposing surfaces of the ferromagnetic oxide and the ferromagnetic metal thin film act as an operating gap during reproduction, but during recording, the saturation magnetic flux density Bs is different. The magnetic field is blunted on the ferromagnetic oxide side, and not all of it acts effectively as a working gap. In other words, the effective track width differs between recording and reproduction. Such a difference in effective trunk width causes crosstalk and the like.

On the other hand, the track width regulating grooves (101a) and (10
There are limits to the accuracy of cutting and the matching accuracy of the magnetic core halves in 2a), and the ferromagnetic metal thin film (105), (
106) is difficult to match completely, resulting in a significant decrease in yield.

Therefore, the present invention has been proposed in order to eliminate the drawbacks of the above-mentioned conventional devices.
The object of the present invention is to provide a magnetic head that can achieve excellent electromagnetic conversion characteristics by effectively utilizing the high saturation magnetic flux density of the film, and is also excellent in terms of productivity.

E1 Means for Solving Problems In order to achieve the above object, the present invention provides a magnetic core made of a ferromagnetic oxide and a ferromagnetic thin film formed on the ferromagnetic thin film forming surface of the magnetic core by vacuum thin film forming technology. A half-pair of magnetic cores is formed from the ferromagnetic metal thin film, and a magnetic gap is formed by abutting the ferromagnetic metal thin films, and the magnetic gap is formed with the ferromagnetic thin film forming surface on the surface facing the magnetic recording medium. In a magnetic head in which the abutted ferromagnetic metal thin films are arranged in a substantially straight line while the surfaces thereof are inclined at a predetermined angle, the ferromagnetic metal thin film of one magnetic core half pair is connected to the ferromagnetic metal thin film of the other magnetic core half pair. It is characterized in that it does not face the oxide at the magnetic gap forming surface.

F1 effect By abutting the ferromagnetic metal thin film of one magnetic core half pair against the ferromagnetic oxide of the other magnetic core half pair so that they do not face each other on the magnetic gap forming surface, the optical magnetic gap length (i.e., visually The magnetic gap length when observed is approximately equal to the effective gap length during recording or the effective gap length during reproduction.

G. Example Embodiments of the present invention will be described below with reference to the drawings.

G-■ FIG. 1 is an external perspective view showing an example of a composite magnetic head to which the present invention is applied, and FIG. 2 is an enlarged plan view of the main part showing the magnetic tape contacting surface thereof. This magnetic head has a ferromagnetic metal thin film formed continuously from the front end, which is the tape contacting surface of the head, to the rear end, which forms the back gap.

In this magnetic head, a magnetic core portion (11).

(12) is formed of a ferromagnetic oxide, such as Mn-Zn ferrite, and these magnetic core parts (11) and (12)
The ferromagnetic thin film formation surface (11a
), (12a) include a ferromagnetic metal f11 film (13A), (13B) which is a high magnetic permeability alloy, for example, a Fe-AIf-3i alloy film, continuously extending from the front gap forming surface to the hack gap forming surface. ) are deposited using vacuum thin film formation technology, and each magnetic core half pair (+)
, (■). Then, these pair of magnetic core halves (1) and (II) are butted together via a gap material such as 5iC)z, and the above ferromagnetic metal thin film (13
The contact surfaces of A) and (13B) are configured to form a magnetic gap g having a track width TW.

Ferromagnetic metal thin film 1 deposited on each of the above magnetic core halves (1) and (II)! (13A) and (13B) are
When viewed from the magnetic tape contact surface, the bonding surface (10) is a nearly straight line and is the abutting surface of the magnetic core halves (1) and (II), that is, the magnetic gap forming surface (10).
It is inclined at an angle θ with respect to the

Here, the ferromagnetic thin film forming surface (lla), (12
The angle θ between a) and the magnetic gap forming surface (10) is 2
It is preferable to set it within the range of 0° to 80°. Here, if the angle is less than 20 degrees, crosstalk from adjacent tracks will increase, so it is desirable to have an angle of 30 degrees or more. Furthermore, if the above-mentioned inclination angle is 90°, the wear resistance will be poor, so it is preferable to set it to about 80° or less. Further, if the inclination angle is 90°, it is not preferable because it takes a lot of time to form a thin film using vacuum thin film forming technology and the film structure becomes non-uniform.

In addition, the above ferromagnetic metal 1 film (13A), (13B)
Examples of the material include ferromagnetic amorphous metal alloys, so-called amorphous alloys (for example, alloys consisting of one or more elements of Fe, Ni, and Co and one or more elements of P, C, B, and Si, or The main component is Al1.Ge.

Be, Sn, Inn, Mo, W, Ti, Mn, Cr.

Metal-metalloid amorphous alloys such as alloys containing Zr, Hf, Nb, etc., or Co, Hr.

Metals whose main components are transition elements such as Zr and rare earth elements.
metal type amorphous alloy), Sendust alloy which is Fe-1-3i type alloy, Fe-Aff type alloy, Fe-3
I-based alloys, Fe-3i-Co-based alloys, permalloy, etc. can be used, and their film deposition methods include flash deposition 1 vacuum evaporation, ion blasting, sputtering, and the Claskoo ion beam method. vacuum al
19 formation techniques are employed.

When using the above-mentioned Fe-Al4-3i alloy, the ferromagnetic metal thin films (13A) and (13B) have columnar structures whose growth direction is on the ferromagnetic thin film forming surface of the magnetic core portions (11) and (12). (lla) and (12a) are preferably applied so as to be inclined at a predetermined angle, for example, an angle of 5° to 45°. In this way, the ferromagnetic metal thin It! A ferromagnetic metal thin film (13A), (13B) obtained by growing (L3A), (13B) at a predetermined angle with respect to the normal direction of the ferromagnetic thin film formation surface (lla), (12a). 13B)
The magnetic properties of the magnetic head become stable and excellent, and the quality and performance of the obtained magnetic head are therefore improved.

In addition, the above ferromagnetic metal FilJ film (13A), (1
3B) is formed as a single layer by vacuum thin film formation technology in this example, but for example, S! Oz, T a 2
05. A it zoi.

Z r 02. A plurality of layers may be formed via a highly wear-resistant insulating film such as S i 3N4. In this case, the number of laminated ferromagnetic metal thin films can be set arbitrarily.

On the other hand, near the formation surface of the magnetic gear g, that is, on both sides of the magnetic gear and the g, in contact with the air tape, the track width is regulated and the ferromagnetic metal thin film (13A), (
Non-magnetic material (14A) to prevent wear of 13B)
, (14B) and (158) , (15B) are (f
It is filled with fusion. Here, the above ferromagnetic metal thin film (1
3^), a track width regulating groove (llb) cut so that a magnetic gap g is formed only by (13B),
Since the processing position accuracy of (12b) is moderate, a portion of the magnetic core portions (11) and (12) remains on the magnetic gap forming surface (10).

In the present invention, the end faces (11c) and (12c) of the ferromagnetic oxide remaining on the magnetic gap forming surface (10) are connected to the magnetic gap between the ferromagnetic metal thin film (13A) or the ferromagnetic metal thin film (13B), respectively. The ferromagnetic metal thin film (13A), so as not to face each other on the formation surface (10),
(13B) are butted against each other with a slight shift.

That is, either the magnetic core half pair (1,) are shifted in the direction of the arrow X in FIG.
I) in the direction of the arrow Y in FIG.
) and the ferromagnetic metal thin film (13A) on the magnetic gap forming surface (
10) are arranged so that they do not face each other.

G-■ According to the inventor's experiments, when a ferromagnetic metal thin film and a ferromagnetic oxide face each other at the magnetic gap forming surface, the effective track width is equal to the optical track width (the ferromagnetic metal thin films are butted against each other). The magnetic gap tiger formed by
It was found that the ferromagnetic metal thin film-ferromagnetic oxide facing length is larger than the width TW0), and it is larger during reproduction than during recording. On the other hand, magnetic core half pair (I)
.

(n) was shifted, and the ferromagnetic metal thin film (13A
), (13B) and the end face of strong Lil oxide (llc)
, (12c) It was found that in the magnetic five-node structure configured so that the lines do not butt each other, the optical track width, the effective track width during recording, and the effective track width during playback are approximately equal.

For example, as schematically shown in FIG. 3, when the half pairs of magnetic cores were butted against each other so that the ferromagnetic oxide and the ferromagnetic metal thin film did not face each other, the reproduction sensitivity and recording sensitivity were measured. Characteristics as shown in Figs. and 6 were obtained.

These drawings show the relationship between the optical track width TWo, the distance ΔX from the center, the optical track width TWo, and the relative sensitivity Δeout with respect to the center.
is the sensitivity of the luminance signal, AFM is the sensitivity of the audio FM signal, C is the sensitivity of the chroma signal, and P is the sensitivity of the pilot signal. The same applies to the following drawings.

Here, when the optical track width Tw0□ is 13.5 μm, the effective track width of Y during reproduction is 14.5 μm.
m, the effective track width of AFM is 16.5 μm, the effective track width of C is 18.0 μm, and the effective track width of P is 31
．． 5 μm, while the effective track width in y during recording was +5.0. IIm, the effective trunk width of AFM is 1
5.5 μm, effective track width of C is 16.0 μm, effective track width of P is 20°0/Jm, optical track 1 depth - effective track width (during reproduction) - effective track width (
(at the time of recording).

On the other hand, as schematically shown in FIG. 4, when a ferromagnetic oxide and a ferromagnetic metal thin film are butted against each other with lengths FX, FX2 (optical track width T Wopt =
23.0 μm), the playback sensitivity characteristics are shown in Figure 7.
The recording sensitivity characteristics are as shown in Figure 8, and the effective track width during playback is T Wapt + F
+ +F X 2 , which is substantially equal to, and is larger than the effective track width during recording.

Using the same method, the values of optical track width TWo□, Tw6. t, X I, X z, FX l+
As Comparative Example 1 and Comparative Example 2 by changing the value of F X z,
We determined the playback sensitivity characteristics and recording sensitivity characteristics, respectively.
The effective track width was determined. The results are shown in the table below. The units are all μm, and the numerical values in parentheses are relative values when the optical track width TW, , □ is set to 0.

(Left below) From this table, it can be said that the effect of the butting state of the magnetic core halves on the effective track width is extremely large.

G-■ Next, in order to make the structure of the magnetic head of the above embodiment more clear, a manufacturing method thereof will be explained.

In order to manufacture the above-mentioned magnetic head, first, as shown in FIG. Forming a plurality of parallel first kerfs (21) with a cross-sectional shape of a square cross section using a rotary grindstone or the like on the joint surface of the substrate (20) when the magnetic core halves are butted together,
A ferromagnetic thin film forming surface (21a) is formed. Note that the ferromagnetic thin film forming surface (21a) is formed on the ferromagnetic oxide substrate (
Upper surface (20a) corresponding to the magnetic gap forming surface of 20)
is formed as a slope so as to be inclined at a predetermined angle θ,
The angle θ is here set to approximately 45°.

Next, as shown in FIG. 10, the ferromagnetic thin film formation surface (
A Fe-AA-Si alloy, an amorphous alloy, etc. is deposited over the entire upper surface (20a) of the substrate (20a) including 21a) using a vacuum thin film forming technique such as sputtering, ion blasting, or vapor deposition. , forming a ferromagnetic metal thin film (22).

Next, as shown in FIG. 11, a ferromagnetic metal thin film (22
) is filled with a non-magnetic material (23), and then the upper surface (20
A) is surface-ground to provide a smooth surface, and the ferromagnetic thin film forming surface (2) is placed on the upper surface (20a) of the substrate (20).
1a) exposing the end face of the ferromagnetic metal thin film (22) deposited thereon; Note that here, the ferromagnetic metal thin film (22)
A protective film may be provided by sputtering a non-magnetic material such as SiO□ or Cr on the surface of the non-magnetic material (23) in advance to prevent erosion during melt filling of the non-magnetic material (23).

Next, as shown in FIG. 12, the ferromagnetic thin film formation surface (21a) on which the ferromagnetic metal F'l film (23) is deposited is formed.
A second kerf (24) is cut in parallel to the first kerf (21) adjacent to the upper surface (2) of the substrate (20).
Apply mirror finishing to 0a). Here, the cutting position of the second cutting groove (24) is -
Side 1! Ideally, it should completely match (21b), but in order to moderate the machining accuracy, some strong chemical compounds should remain.

Note that the shape of the second cut rM (24) may be any shape, such as a polygonal cross-section or a substantially semicircular cross-section.
When viewed from the tape facing surface of the magnetic head, a distance between the strong oxide and the ferromagnetic metal thin film is ensured.

With such a groove shape, it is possible to reduce the crosstalk component caused by reproducing a long wavelength component signal while keeping the bonding area between the ferromagnetic oxide and the ferromagnetic metal thin film large. Furthermore, by forming the above-mentioned shape, the end face of the ferromagnetic oxide is tilted in a direction different from the azimuth angle of the magnetic gap, and the amount of pink-up of signals from adjacent or adjacent tracks due to azimuth loss, i.e. Crosstalk can be reduced.

As shown in FIG. 13, the first cut /I( 21) and a groove in a direction perpendicular to the second kerf (24),
A winding groove (25) is formed to obtain a ferromagnetic oxide substrate (30).

Subsequently, a gap spacer is attached to at least one of the upper surface (20a) of the substrate (20) and the upper surface (30a) of the substrate (30), as shown in FIG.
These substrates (20) and (30) are bonded and arranged so that the ferromagnetic metal thin films (22) are butted against each other.

At this time, the substrate (30) or the substrate (20) is shifted in the direction of arrow R or in the direction indicated by the arrow in FIG. 14 so that the ferromagnetic metal thin film (22) does not face the ferromagnetic oxide.

Then, at the same time as these groups Fi (20) and (30) are fused with glass, the second kerf (24) is filled with the non-magnetic material (26). In addition, as the above-mentioned gap spacer, S I Oz+ Z r Oz, T
azos+Cr etc. are used. In addition, in this manufacturing process, the non-magnetic material (26
) is not filled at the same time as the fusion of the substrates (20) and (30), but by filling the second kerf (24) with a non-magnetic material (26) in advance in the process shown in FIG. 12, for example. In the step shown in FIG. 14, only glass fusion may be performed.

After cutting out a plurality of head chips by slicing at the positions of line A-A and line A'-A' in FIG.
The n-type head shown in the figure is completed. At this time, by making the slicing direction of the substrates (20) and (30) inclined with respect to the abutting surfaces, a magnetic head for azimuth recording can be fabricated.

Here, one magnetic core part (11) of this magnetic head has a ferromagnetic oxide substrate (20) as a base material, and the other magnetic core part (12) has a ferromagnetic oxide substrate (30) as a base material. It is said that In addition, ferromagnetic metal thin film (13A), (1
3B) is ferromagnetic oxide 1ll (22), non-magnetic material (1
44) and (14B) correspond to the non-magnetic material (23), and the non-magnetic materials (15A) and (15B) correspond to the non-magnetic material (26), respectively.

Although specific examples of the present invention have been described above, the present invention is not limited to these examples. For example, a magnetic head in which a ferromagnetic metal film is deposited only in the vicinity of the magnetic gap, a magnetic head in which a ferromagnetic metal thin film is bent at a position away from the magnetic gap, etc., within the scope of the present invention. It is applicable to various magnetic heads.

Effects of the H0 Invention As is clear from the above explanation, in the magnetic head of the present invention, the half pairs of magnetic cores are arranged so that the ferromagnetic oxide and the ferromagnetic gold W; and the thin film do not face each other on the magnetic gap forming surface. Since they are offset and matched, the optical track width and the effective track width during recording are the same.

Alternatively, it is possible to provide a magnetic head in which the effective track widths during reproduction are approximately equal, and the high saturation magnetic flux density characteristics of the ferromagnetic metal thin film can be effectively utilized. Furthermore, since the effective track widths during recording and reproduction are approximately the same, there is less risk of crosstalk and the like, which is advantageous for increasing recording density.

Furthermore, since the machining accuracy of the grooves provided to regulate the track width and the butting accuracy of the ferromagnetic metal thin films are moderate, the effect is large in terms of productivity.

[Brief explanation of drawings]

FIG. 1 is an external perspective view showing an embodiment of a magnetic head to which the present invention is applied, and FIG. 2 is an enlarged plan view of a main part showing the magnetic tape contacting surface thereof. FIG. 3 is a schematic diagram of the magnetic head of the present invention in which the ferromagnetic metal thin film is butted against each other, and FIG. 4 is a schematic diagram of the magnetic head in which the ferromagnetic metal thin film and the ferromagnetic oxide are opposed to each other. . FIG. 5 is a characteristic diagram showing reproduction sensitivity characteristics in a magnetic head in which a ferromagnetic metal thin film and a ferromagnetic oxide are butted against each other so as not to face each other, and FIG. 6 is a characteristic diagram showing recording sensitivity characteristics. FIG. 7 is a characteristic diagram showing the reproducing sensitivity characteristics of a magnetic head in which a ferromagnetic metal thin film and a ferromagnetic oxide face each other, and FIG. 8 is a characteristic diagram showing the recording sensitivity characteristics. FIGS. 9 to 14 are schematic perspective views showing the manufacturing process for producing the magnetic nozzle shown in FIG. FIG. 11 shows the metal thin film forming step, FIG. 11 shows the glass filling and surface polishing step, FIG. 12 shows the second kerf processing step, FIG. 13 shows the winding groove processing step, and FIG. 14 shows the glass fusing step. FIG. 15 is an external perspective view showing a conventional magnetic head.

Claims (1)

[Claims] A magnetic core half pair is constituted by a magnetic core made of a ferromagnetic oxide and a ferromagnetic metal thin film formed by a vacuum thin film formation technique on the ferromagnetic thin film forming surface of the magnetic core, A magnetic gap is formed by abutting the ferromagnetic metal thin films, and the ferromagnetic thin film forming surface and the magnetic gap forming surface are inclined at a predetermined angle on the surface facing the magnetic recording medium, and the abutted ferromagnetic metal A magnetic head having thin films arranged in a substantially straight line, characterized in that the ferromagnetic metal thin film of one half-pair of magnetic cores does not face the ferromagnetic oxide of the other half-pair of magnetic cores on the magnetic gap forming surface. head.