JP2625838B2 - Magnetic head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used for recording and reproducing on a high coercive force magnetic recording medium such as a so-called metal tape.

[Summary of the Invention]

According to the present invention, a pair of magnetic core halves each having at least one magnetic core half composed of an oxide magnetic material and a metal magnetic thin film are abutted, and a magnetic gap is formed on the abutting surface of the metal magnetic thin film. In the magnetic head, the interface between the metal magnetic thin film and the oxide magnetic material has an electronegativity.
By arranging an oxygen-containing thin film made of a metal or alloy of 1.9 or more as a reaction prevention film, the reaction between the metal magnetic thin film and the oxide magnetic material is prevented to suppress the generation of a pseudo gap, and electromagnetic It is intended to improve conversion characteristics and reproduction output characteristics.

[Prior Art] For example, in a magnetic recording / reproducing apparatus such as a VTR (video tape recorder), recording of short-wavelength information signals has been promoted for the purpose of improving image quality and the like. High coercive force magnetic recording media such as so-called metal tapes using powder or so-called vapor-deposited tapes in which a ferromagnetic metal material is directly applied on a base film have been used.

In the field of magnetic heads, on the other hand, research is being carried out to cope with this, and various magnetic heads using a metal magnetic thin film for a magnetic core have been developed as magnetic heads suitable for high coercive force magnetic recording media.

As an example of such a magnetic head, for example, a magnetic head configured as shown in FIG. 8 is known.

In the magnetic head, as shown in FIG. 8, a pair of left and right magnetic core halves (I) and (II) produced separately from each other with a magnetic gap G as a boundary, but are joined and integrated by, for example, glass fusion. It is.

Here, the magnetic core halves (I) and (II) are composed of auxiliary core portions (1) made of an oxide magnetic material such as ferrite.
Metal magnetic thin films (3) and (4) are formed on the facing surfaces of (2) from the front side to the back side, respectively. A magnetic gap G is formed by abutting these metal magnetic thin films (3) and (4) with a gap spacer (not shown) sandwiched therebetween. A winding groove (5) for winding a coil is formed in the one auxiliary core portion (2).

Since the magnetic head is formed of a metal magnetic thin film (3) or (4) having a high saturation magnetic flux density in the vicinity of the magnetic gap G, for example, a ferromagnetic metal thin film such as Sendust, a magnetic field generated from the magnetic gap G is formed. The strength is increased, making it suitable for a high coercive force magnetic recording medium such as a metal tape.

[Problems to be solved by the invention]

The metal magnetic thin films (3) and (4) are usually formed by a vacuum thin film forming technique such as a sputtering method.
For this reason, oxygen is transferred at interfaces K ₁ and K ₂ between the metal magnetic thin films (3) and (4) and the auxiliary cores (1) and (2) made of ferrite, and a diffusion layer may be formed. There is.

That is, when the metal magnetic thin films (3) and (4) are deposited on the auxiliary core portions (1) and (2) made of ferrite by, for example, sputtering, the ferrite is unstable as an oxide, so that the ferrite is not stable. Oxygen atoms forming the ferrite are diffused by the heat of the ferrite and are combined with Fe atoms, Al atoms or Si atoms forming the sendust.
As a result, the ferrite at the interfaces K ₁ and K ₂ is in a reduced state, and the metal magnetic thin films (3) and (4) are in an oxidized state, so that a so-called diffusion layer is formed. This diffusion layer is close to non-magnetic, and not only increases the magnetic resistance between these auxiliary cores (1) and (2) and the metal magnetic thin films (3) and (4) but also reduces the efficiency. In particular, when it is positioned in parallel with the magnetic gap G, it operates as a so-called pseudo gap that causes undulation in the frequency characteristics, causing deterioration of the recording / reproducing signal. For this reason, it is difficult to apply the present invention to a magnetic head such as an 8 mm video tape recorder which requires high performance.

The diffusion layer is generated not only when the metal magnetic thin films (3) and (4) are formed, but also when the glass cores (I) and (II) are joined and integrated. Sometimes.

Therefore, it is conceivable to prevent the formation of the diffusion layer by disposing a thin film such as an oxide or a nitride made of, for example, SiO ₂ or Si ₃ N _{4 at the} interfaces K ₁ and K ₂ as a reaction prevention film. As a result of repeated studies by the present inventors, these SiO ₂ films and Si ₃ N ₄ films did not effectively eliminate the pseudo gap.

That is, if the thickness of the SiO ₂ film or the Si ₃ N ₄ film is large, diffusion at the interfaces K ₁ and K ₂ can be prevented, but since these thin films are nonmagnetic, they depend on the film thickness. As a result, the reaction prevention film itself may operate as a pseudo gap. Conversely, when the thickness of these reaction preventing films is reduced,
Diffusion easily occurs through the thin film of the SiO ₂ film or the Si ₃ N ₄ film, and a diffusion layer is formed. The diffusion layer also operates as a pseudo gap, and swells the reproduced signal.

Therefore, the present invention has been proposed to solve the above-described problems, and prevents a reaction between a metal magnetic thin film and an oxide magnetic material, thereby reducing the effect of a pseudo gap to reduce electromagnetic interference. An object of the present invention is to provide a magnetic head having excellent conversion characteristics and recording / reproducing characteristics.

[Means for solving the problem]

The present inventors have conducted extensive studies with the achievement of the above-mentioned object, and found that a thin film mainly composed of a metal or alloy having an electronegativity of 1.9 or more is effective in preventing a reaction at the interface. To complete the present invention.

That is, in the magnetic head of the present invention, at least one of the magnetic core halves has a pair of magnetic core halves each formed of an oxide magnetic material and a metal magnetic thin film, and a magnetic gap is formed at the abutting surface of the metal magnetic thin films. A magnetic head formed, wherein a thin film made of a metal or alloy having an electronegativity of 1.9 or more is disposed as a reaction preventing film between the metal magnetic thin film and the oxide magnetic material, and the reaction preventing film is formed. Is characterized by containing oxygen.

The electronegativity indicates the ability to attract electrons when an atom forms a chemical bond. In this specification, a value determined by Pauling (L. Pauling) is used.

[Action]

Electronegativity indicates the ability of the element to attract electrons, and its value is approximately proportional to the sum of ionization energy and electron affinity. Then, it can be said that as the combination of elements has a larger difference in electronegativity, electrons are attracted to one side, the ionicity of the bond increases, and the combination becomes chemically stable.

From this point of view, metals having an electronegativity of 1.9 or more have a weaker bonding force to oxygen than metal atoms (Fe, Mn, Zn, etc.) constituting oxide magnetic materials, for example, ferrite. Even if it is in contact, oxygen in the ferrite does not migrate into the metal.

Therefore, when a thin film of a metal or alloy having an electronegativity of 1.9 or more is interposed between the oxide magnetic material and the metal magnetic thin film as a reaction prevention film, the thin film acts as a barrier, and sputtering and glass fusion are performed. Transfer and diffusion of oxygen constituting the oxide magnetic material to the metal magnetic thin film side are suppressed even after the heat treatment.

Further, if the reaction prevention film is made of an alloy of a metal having a electronegativity of 1.9 or more and a magnetic metal, the reaction prevention film itself will be provided with magnetism, which not only suppresses the diffusion of oxygen but also reduces the magnetic field. Deterioration is reduced.

Further, if oxygen is introduced into the above-mentioned thin film made of a metal or alloy having an electronegativity of 1.9 or more, or a thin film made of an alloy of a metal and a magnetic metal having an electronegativity of 1.9 or more, an oxide magnetic material-metal magnetic thin film can be obtained. The oxygen concentration gradient between them is reduced, and the transfer and diffusion of oxygen to the metal magnetic thin film side is further suppressed.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the magnetic head of this embodiment has auxiliary cores (6) and (7) made of an oxide magnetic material such as Mn-Zn ferrite or Ni-Zn ferrite. The magnetic core thin films (8) and (9) are formed by joining and joining pairs of magnetic core halves (III) and (IV) having the main components.

Here, the magnetic gap g is formed by abutting the metal magnetic thin films (8) and (9) with a gap spacer (not shown) sandwiched therebetween. Core part (6),
The track width Tw of the magnetic gap g is determined by the track width regulating grooves (10) and (11) provided in (7), and the track width Tw is smaller than the head chip thickness Cw.

In the magnetic head of the present embodiment, the metal magnetic thin films (8) and (9) near the magnetic gap g are
And therefore, the track width can be increased irrespective of the thickness of the metal magnetic thin films (8) and (9), and the track width accuracy can be improved.
The efficiency of this film forming process can be improved.

The notched portions cut off by the track width regulating grooves (10) and (11) are filled with bonding glasses (12) and (13) to ensure the contact characteristics with the magnetic recording medium. .

A winding groove (14) as a groove for winding a coil is provided in the middle of the abutting surface of one of the auxiliary cores (6) constituting the magnetic core halves (III) and (IV). Are formed.

The metal magnetic thin films (8) and (9) are connected to the winding groove (1).
4) It is formed from the front side to the back side along the abutting surfaces of the auxiliary core portions (6) and (7), including the inside. Therefore, the magnetic core half (III),
(IV) By joining and integrating each other, the metal magnetic thin film (8) having a high saturation magnetic flux density near the magnetic gap g,
The magnetic field strength at the magnetic gap g is increased by (9), and a magnetic head suitable for a high coercive force magnetic recording medium such as a metal tape is realized.

Ferromagnetic materials having a high saturation magnetic flux density and excellent soft magnetic properties are used for the metal magnetic films (8) and (9). Can also be used, regardless of whether it is crystalline or non-crystalline. For example, Fe-Al-Si alloy, Fe-Al alloy, Fe-Si
-Co alloy, Fe-Ni alloy, Fe-Al-Ge alloy, Fe-Ga
Ferromagnetic metal materials such as -Ge alloys, Fe-Si-Ge alloys, Fe-Co-Si-Al alloys, or Fe-Ga-Si alloys, and further, the above Fe-Ga-Si alloys In order to further improve the corrosion resistance and abrasion resistance of alloys, alloys containing Fe, Ga, Co (including those where Fe is partially replaced by Co) and Si,
n, Zr, Nb, Mo, Ta, W, Ru, Os, Rh, Ir, Re, Ni, Pd, Pt, Hf and V may be added.

Ferromagnetic amorphous metal alloys, so-called amorphous alloys (for example, alloys composed of one or more elements of Fe, Ni, Co and one or more elements of P, C, B, Si, or Metal-metalloid amorphous alloys such as alloys containing Al, Ge, Be, Sn, In, Mo, W, Ti, Mn, Cr, Zr, Hf, Nb, etc., or transitions of Co, Hf, Zr, etc. A metal-metal-based amorphous alloy containing an element or a rare earth element as a main component is also used.

As a method of forming these metal magnetic films (8) and (9), a vacuum thin film forming technique represented by a vacuum evaporation method, a sputtering method, an ion plating method, a cluster ion beam method, or the like is employed.

Further, the metal magnetic films (8) and (9) may be single-layer films of the ferromagnetic alloy material, for example, SiO ₂ , Ta ₂ O ₃ , A
l ₂ O _3, ZrO _2, or a multilayer film via an insulating film such as Si ₃ N _4.

In the magnetic head of this embodiment, the reaction preventing film (15) is provided on the interfaces k ₁ and K ₂ between the metal magnetic thin films (8) and (9) and the auxiliary cores (6) and (7). , (16) are formed.

The material of the reaction prevention films (15) and (16) is, for example, a metal having an electronegativity of 1.9 or more, or an alloy thereof.

Metals having an electronegativity of 1.9 or more include Re, Cu, Ag,
Au, Ru, Rh, Pd, Os, Ir, Pt and the like can be mentioned. Among them, platinum group elements (Ru, Rh, Pd, Os, Ir, Pt) having an electronegativity of 2 or more are preferable. In addition, the metal alone is used as a reaction prevention film (15),
(16) or an alloy film combining metals having an electronegativity of 1.9 or more.

These metals are chemically stable compared to the metal elements (Fe, Mn, Zn, etc.) constituting the oxide magnetic material and are difficult to bond with oxygen. Metal magnetic thin films (8) and (9) and auxiliary core parts (6) and (7)
It serves to prevent reactions at the interfaces k ₁ and k ₂ with.

The above-mentioned reaction prevention films (15) and (16)
Not only a combination of 1.9 or more metals, but also an alloy in which the metal (a metal having an electronegativity of 1.9 or more) and a magnetic metal are combined.

In this case, usable magnetic metals include Fe, Co, and Ni.

By forming an alloy with these magnetic metals, the reaction preventing films (15) and (16) are also provided with magnetism, so that magnetic degradation caused by interposition at the interface can be minimized.

In the case of forming an alloy with the magnetic metal, the proportion of the metal having an electronegativity of 1.9 or more contained in the alloy is preferably 2 atomic% or more, and if it is less than this, the diffusion preventing effect becomes insufficient. .

In the present invention, oxygen is introduced into the reaction prevention films (15) and (16) made of a metal, an alloy or an alloy with a magnetic metal having an electronegativity of 1.9 or more.

According to this, between the auxiliary core portions (6) and (7) and the reaction prevention films (15) and (16), and between the reaction prevention films (15) and (16) and the metal magnetic thin films (8) and (9). The change in the oxygen concentration gradient between the auxiliary core portions (6) and (7) is reduced, and the movement of oxygen atoms constituting the auxiliary core portions (6) and (7) is suppressed, and the formation of a diffusion layer is prevented.

As a method for introducing oxygen into the reaction preventing films (15) and (16), the above-mentioned metals such as Re, Cu, Ag, Au or Ru, Rh, Pd, O
When a platinum group metal such as s, Ir, or Pt is formed on the auxiliary core portion by sputtering, vapor deposition, or the like, a method of introducing oxygen gas into the atmosphere may be used. The amount of oxygen gas introduced at this time may be, for example, in the case of sputtering, such that about 10% of the oxygen gas is mixed into Ar gas which is a normal atmosphere. If the amount of the introduced oxygen gas is excessive, the sputtering efficiency may be reduced.

Thereby, oxygen is forcibly dissolved in the formed thin film. Needless to say, oxygen may be introduced in the form of a metal oxide having an electronegativity of 1.9 or more, instead of the form in which oxygen penetrates between metals.

The reaction prevention films (15) and (16) may be a single-layer film made of a metal or alloy having an electronegativity of 1.9 or more and oxygen introduced as described above, or a multi-layer film obtained by combining these. It may be a laminated film combined with a film or a magnetic metal film.

Therefore, as the laminated film, a metal or alloy film having an electronegativity of 1.9 or more and a metal or alloy film containing oxygen having an electronegativity of 1.9 or more, or an electronegativity of 1.9 or more.
The above metal or alloy film, a laminated film of a magnetic metal and alloy film containing oxygen, a metal or alloy film having an electronegativity of 1.9 or more, a laminated film of a magnetic metal film containing oxygen, A stacked film of metal or alloy films containing electronegativity 1.9 or more containing oxygen, a metal or alloy film containing oxygen 1.9 or more containing oxygen, and a metal having an electronegativity 1.9 or more,
A laminated film composed of an alloy film of a magnetic metal and a metal or alloy film containing electronegativity 1.9 or more containing oxygen, a laminated film composed of a magnetic metal, and a metal containing electronegativity 1.9 or more containing oxygen, A laminated film composed of a magnetic metal alloy film and a magnetic metal film is exemplified.

In this case, it is preferable that diffusion does not occur between the layers of the laminated film, and therefore, it is preferable that the combination is such that the mutual affinity potential is negative.

For example, when a metal having an electronegativity of 1.9 or more is to be multilayered, a combination of Pd-Pt, Pd-Rh, or the like is used.

As is clear from the phase diagram shown in FIG. 3, the Pd-Pt laminated film is separated into two phases at a temperature of about 800 ° C. or less in the Pd-50% Pt laminated film. That is, if the films are formed in the order of Pt-Pd-Pt, this means that the laminated film exists stably up to about 800 ° C.

Similarly, in the case of a laminated film composed of a metal film having an electronegativity of 1.9 or more and a magnetic metal film, a combination of Ag-Fe or the like is preferable, and in the case of an Ag-Fe system, it is not mixed in a solid phase or a liquid phase. Are known. Such a combination has been actively studied in the field of artificial lattice films and the like. Therefore, a combination which is stable at high temperature and has magnetism may be selected from these. In particular, in the case of a laminated film in which the magnetic metal films are combined, the substantial nonmagnetic layer can be reduced to a thickness of about several atomic layers, and the output due to the reduction of the pseudo gap effect and the reduction of the magnetoresistance. Is achieved.

The film thickness of the reaction preventing films (15) and (16) is preferably 1000 ° or less in each case, and practically 5 ° or more and 1/10 or less of the optical gap length. It is preferred that That is, if the thickness of the reaction preventing films (15) and (16) is smaller than this range, the effect of preventing the reaction cannot be obtained, and if the film is thicker, adverse effects due to the pseudo gap may occur. In particular, in the case of forming a laminated film, the effect of preventing the reaction is extremely high.

As described above, in the magnetic head of this embodiment, the diffusion layer is formed at the interface between the metal magnetic thin film and the oxide magnetic material by the interposition of the reaction prevention films (15) and (16) formed of the above-mentioned materials. Since there is no such condition, it is possible to control the conditions for depositing the metal magnetic thin film, for example, the conditions such as the sputtering temperature and the sputtering rate under mild conditions. Further, since conditions such as heat treatment at the time of glass fusion are relaxed, it is advantageous in terms of improvement in yield, management of manufacturing conditions, and the like, and sufficiently satisfactory in reliability.

In the magnetic head of this embodiment, the track width regulating grooves (10) and (11) are obliquely cut at both ends of the magnetic gap g with respect to both magnetic core halves (III) and (IV). Although the track width Tw is determined, for example, the track width may be defined by only one magnetic core half (III) as shown in FIG.

That is, for one magnetic core half (III),
The metal magnetic thin film (8) after the deposited and formed, cutting out the magnetic gap g vicinity by L ₂ becomes wide matches a predetermined track width Tw. On the other hand, regarding the magnetic core half (IV), the track width regulation (11) is provided in advance on the auxiliary core part (7), and then the metal magnetic thin film (9) is applied. Width L ₂ of the magnetic core half (IV) side
Is set to be slightly larger than the actual track width Tw.

With such a setting, the magnetic core halves (III), (I
Even if a track shift occurs at the time of joining of V), the track width Tw is equal to the length L of the butted surface of the magnetic core half (III).
Regulated by ₂ . Furthermore, since both ends of the magnetic gap g become clear, the track width Tw is accurately controlled.

In FIG. 4, the same members as those of the magnetic head shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

Further, in the present embodiment, the magnetic head in which the metal magnetic thin film is formed on both magnetic core halves has been described. However, the present invention is not limited to this. Needless to say, the present invention can be applied to a magnetic head on which a magnetic thin film is formed.

Next, a description will be given of a magnetic head actually manufactured by the present inventors.

Reference Example 1 In this example, among the materials listed above, the electronegativity was 1.9
Using the above metals for the reaction preventing films (15) and (16), a magnetic head (a magnetic head for an 8 mm video tape recorder) as shown in FIG. 1 was manufactured.

That is, the Pt and Pd metals are respectively reacted with a reaction prevention film (15),
(16) and sputtered on the auxiliary cores (6) and (7) made of Mn-Zn ferrite, and Fe-Ga-
Metal magnetic thin film made of Si-Ru (8), to prepare a magnetic core halves by adhering the (9), these magnetic cores halves and glass fusing sandwich the SiO ₂ film as a gap spacer. The thicknesses of the Pt and Pd metals were each set to 60 °, the thickness of the metal magnetic thin films (8) and (9) was 4 μm, and the thickness of the SiO ₂ film was 12 μm.
50 mm.

For comparison, a metal magnetic thin film (8) of Fe—Ga—Si—Ru is directly provided on the auxiliary cores (6) and (7) made of ferrite without providing the reaction prevention films (15) and (16). , (9) are applied to form magnetic core halves, and these magnetic core halves are
A magnetic head was manufactured by fusing glass with an O ₂ film interposed as a gap spacer. The other conditions were the same as those of the magnetic head.

Then, reproduction was performed using these magnetic heads.
The results are shown in FIGS. 5 and 6. FIG. 5 shows the frequency characteristics of the reproduced signal when the reaction prevention films (15) and (16) made of Pt or Pd are provided, and FIG. 6 shows the reproduction signal of the comparative example head (without the reaction prevention film). FIG.

As a result, Pt or Pd is converted to a reaction prevention film (15), (16)
Frequency characteristics of the magnetic head interposed at the interfaces k ₁ and k ₂ (A shows Pt, B shows Pd, respectively).
Had almost no swell in any case.
That is, the Pt or Pd is converted to a reaction prevention film (15), (1)
The magnetic head interposed in 6) had an extremely small undulation width of 0.3 to 0.5 dB, and thus was judged to have sufficient performance as a magnetic head for an 8 mm video tape recorder.

Therefore, it can be said that the magnetic head of this example is one in which the formation of the diffusion layer at the interface between the ferrite and the metal magnetic thin film is prevented, and the generation of the pseudo gap causing interference with the original magnetic gap is effectively suppressed.

On the other hand, as shown in FIG. 6, the frequency characteristic of the magnetic head without the reaction preventing films (15) and (16) had a swell width of about 2 to 3 dB. That is, it was shown that a diffusion layer was formed at the interface between the ferrite and the metal magnetic thin film, and this operated as a pseudo gap.

Embodiment of the present invention In this embodiment, oxygen is forcibly solid-dissolved in the reaction prevention films (15) and (16) made of a metal having an electronegativity of 1.9 or more, and this is mixed with the auxiliary core portions (6) and (7). Magnetic thin film (8), (9)
A magnetic head as shown in FIG. 1 was also produced by disposing the magnetic heads at interfaces k ₁ and k ₂ .

In the magnetic head of this embodiment, the auxiliary core (6),
The change in oxygen concentration between (7) and the metal magnetic thin films (8) and (9) was a small value as shown in FIG. That is, since the reaction prevention films (15) and (16) contain oxygen, the auxiliary cores (6) and (7) and the reaction prevention films (15) and (7)
During (16), the oxygen concentration gradient between the reaction preventing films (15) and (16) and the metal magnetic thin films (8) and (9) becomes smaller, and the oxygen concentration gradient at the interfaces k ₁ and k ₂ as a whole. Has become smaller.

For this reason, the oxygen atoms forming the auxiliary cores (6) and (7) move toward the metal magnetic thin films (8) and (9), or the oxygen atoms forming the auxiliary cores (8) and (9) The movement of oxygen atoms toward (6) and (7) was suppressed.

Although some movement of oxygen atoms was observed between the metal magnetic thin films (8) and (9) of the reaction preventing films (15) and (16), they did not significantly affect the magnetic properties.

Reference Example 2 In this example, the reaction prevention films (15) and (16) have an electronegativity of 1.
An alloy composed of nine or more metals and a magnetic metal is used.

That is, an alloy of Fe and Ru, for example, Fe ₈₀ Ru ₂₀ is used as a reaction prevention film (15) or (16) as an interface k between the auxiliary core portions (6) and (7) and the metal magnetic thin films (8) and (9). ₁ , k ₂ and the first
A magnetic head as shown in FIG. The above Fe ₈₀ Ru
The thickness of ₂₀ is 600 mm, while the metal magnetic thin film (8),
For (9), Fe-Ga-Si-Ru was used and its film thickness was 4 μm.

When reproduction was performed using this magnetic head and the frequency characteristics were examined, the width of the undulation was as low as about 0.6 dB, and the reproduction output was 5 MHz and used as a magnetic head for an 8 mm video tape recorder. Practical values were obtained.

〔The invention's effect〕

As is clear from the above description, in the magnetic head of the present invention, at the interface between the metal magnetic thin film and the oxide magnetic material, an oxygen-containing reaction preventing film made of a metal or alloy having an electronegativity of 1.9 or more is provided. As a result, the reaction at the interface is reliably prevented, a diffusion layer that operates as a pseudo gap is not formed, and the undulation of the reproduction characteristics is eliminated.

Further, in the present invention, the thickness of the reaction preventing film can be made extremely thin, and in some cases, magnetism can be imparted. Can be minimized.

Therefore, it is possible to provide a magnetic head having excellent electromagnetic conversion characteristics and exhibiting extremely good reproduction output.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a magnetic head to which the present invention is applied, FIG. 2 is an enlarged plan view of a main part of a sliding surface of a recording medium, FIG. 3 is a state diagram of a Pd-Pt-based laminated film, and FIG. FIG. 4 is an enlarged plan view of a main part showing a sliding surface of a recording medium of another example of the magnetic head, FIG. 5 is a characteristic diagram showing the frequency dependence of the reproduction output of the magnetic head provided with the reaction preventing film, and FIG. FIG. 7 is a characteristic diagram showing the frequency dependence of a magnetic head having no reaction preventing film, and FIG. 7 is a schematic diagram showing a change in oxygen concentration when an oxygen-containing reaction preventing film is interposed. FIG. 8 is a perspective view showing an example of a conventional magnetic head. 6,7… Auxiliary core 8,9… Metal magnetic thin film 15,16… Reaction prevention film

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Junichi Honda 6-5-6 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Magne Products Inc. (72) Inventor Tatsuo Hisamura 6 Kita-Shinagawa, Shinagawa-ku, Tokyo No. 5-6, Sony Magne Products Co., Ltd. (56) References JP-A-63-124208 (JP, A) JP-A-63-279404 (JP, A)

Claims (2)

(57) [Claims] A pair of magnetic core halves each having at least one magnetic core half composed of an oxide magnetic material and a metal magnetic thin film are abutted, and a magnetic gap is formed on the abutting surface of the metal magnetic thin film. A thin film made of a metal or an alloy having an electronegativity of 1.9 or more is disposed as a reaction preventing film between the metal magnetic thin film and the oxide magnetic material, and the reaction preventing film removes oxygen. A magnetic head characterized by containing. 2. The magnetic head according to claim 1, wherein the reaction preventing film is a thin film made of an alloy of a metal having a electronegativity of 1.9 or more and a magnetic metal.