JPH0485713A - Magnetic head - Google Patents

Abstract

PURPOSE:To lessen the degradation in a yield by the air bubble in a gap and a gap increase defect by interposing and forming underlying oxide films at 5 to 25Angstrom thickness and adhesive strength intensifying films at 5 to 200Angstrom thickness. CONSTITUTION:The underlying oxide films 12 are interposed and formed at 5 to 25Angstrom thickness and the adhesive strength intensifying films 6 at 5 to 200Angstrom thickness between ferrite cores 2a, 2b and thin metallic films 5. The underlying oxide films begin to produce influence as a pseudo gap if the film thickness is increased to >= 25Angstrom as regards the thickness of the films 12. In addition, the adhesive property between the ferrite cores 2a, 2b and the films 5 degrades the film peeling arises. Conversely, the underlying oxide films lose their functions and form the layers deteriorated in magnetic characteristics to form the pseudo gap if the thickness of the films 12 is decreased to <= 5Angstrom . There is a problem in the adhesive property to the thin metallic films if the thickness of the adhesive strength intensifying films is <= 5Angstrom . Conversely, the degradation in the magnetic characteristics is induced and the good magnetic head characteristics are not obtainable at >= 200Angstrom .

Description

[Detailed Description of the Invention] The present invention relates to a magnetic head.
Parallel type M used for R-DAT and high-density FDD equipment, etc.
The present invention relates to a magnetic head that achieves high-density recording by improving the gap structure of the IG (Metal In Gap) head.

In the field of magnetic recording, the recording density and frequency of information signals are increasing, and in response to this, ferromagnetic metals such as FerroCo+Ni are being used as magnetic recording media. So-called metal tapes in which powder is used as magnetic powder and so-called vapor-deposited tapes in which magnetic metal materials are directly deposited on base films using vacuum thin film forming techniques such as vapor deposition have been put into practical use and are becoming popular. Under these circumstances, the core material of the magnetic head must have a high saturation magnetic flux density and high permeability in order to perform good recording and reproduction on magnetic recording media with high coercive force and residual magnetic flux density. Various properties are required, such as having magnetic property.

It is difficult to manufacture a magnetic head that satisfies these requirements from a single ferromagnetic oxide material such as ferrite material;
Therefore, a so-called composite magnetic head has been proposed in which a magnetic head is constructed by combining a ferromagnetic metal thin film having a high saturation magnetic flux density, such as Sendust. As is well known, this Sendust
For example, as shown in the magazine "Electronic Materials J, June 1981 issue P2O6, the saturation magnetic flux density Bs is 9500 Gauss + the coercive force Hc is 2
QmOe, effective permeability ueff is 30000 at 3
It has excellent properties such as 00Hz and Vickers hardness Hv of 500.

In the conventional composite magnetic head, as shown in FIGS. 6 to 8, for example, a magnetic core portion 2a has a winding locking groove 9a+9b and a winding insertion hole 10 formed therein.

Ferrite which is the material of 2b and the top end surface 8 of the core chip
In order to improve the adhesion force with the metal thin film 5 forming the magnetic gap g, vapor deposition or sputtering (inert gas atmosphere, In particular, an adhesion reinforcing film 6 is formed to a thickness of 500 to 700 layers using argon gas, etc., and a metal thin film 5 such as Sendust is applied thereon. At this time, the adhesion-strengthening film 6 is selected from metals included in Groups 1 Va to VIa of the periodic table of elements, and for example, Cr and T+ are often used. The magnetic head 1 was obtained by winding a copper wire 7 around the magnetic head portion 2 formed in this manner. In addition, as the adhesion strength-enhancing film 6, instead of using these metals alone, an oxide film 14 for preventing diffusion, that is, a thin film 14 such as SiO2 is used.
By forming a film with a thickness of ~500 mm and sandwiching it to form a laminated structure, a magnetic herad core 15 as shown in FIGS. 9 and 10 was also made.

In addition, in published patent publication No. 1-223GO6, the relative magnetic permeability/film thickness is 100
There is also a patent example that states that by forming a magnetic material called "μm" as an underlayer film, a magnetic head with almost no contour effect can be obtained.

The above-mentioned parallel type MIG head 1 has the advantage of being easy to manufacture in that the groove cutting process is simple.However, in order to manufacture the core chip 2, a desired thin film is sputtered, etc. After forming the ferrite core 2a, the metal such as Cr forming the adhesion strength film 6 undergoes a heat treatment process such as annealing and glass fusion.
, 2b through thermal diffusion, a degraded layer 6a is formed near the interface between the ferrite core 2a + 2b and the adhesion strengthening film 6, and the magnetic properties are degraded.

That is, when the deteriorated layer 6a is formed between the metal thin film 5 parallel to the magnetic gap g, the magnetic resistance of this portion becomes large, resulting in a pseudo gap g15g2 parallel to the magnetic gap g. Then, this MIG head 1
, 15 on the magnetic medium 11, there are disadvantages in that wave characteristics occur in frequency characteristics due to pseudo gaps, and accurate reproduction becomes difficult, resulting in frequent errors.

Furthermore, due to the influence of the above-mentioned diffusion, the gap forming surface g-9g
Microscopic irregularities were formed on the surface of the gear, making it difficult to form an accurate magnetic gap and causing air bubbles within the gear and major defects in the gear.

Also, in the magnetic herad core 15 in which a thin layer 14 of SiO2 or the like is formed as a diffusion prevention film as shown in FIGS. The magnetic properties deteriorate, resulting in a pseudo gap. Furthermore, the thickness of the diffusion prevention layer is 3
If the film is not larger than 00 Å, it will not be possible to stop diffusion, and if it is too thick, it will act as a pseudo gap or the adhesive strength due to Cr will deteriorate, making it extremely difficult to control the film thickness. .

Therefore, the main object of the present invention is to be easy to manufacture and to
It is an object of the present invention to provide a parallel type MIG head having a structure in which waviness in frequency characteristics due to a contour effect from a pseudo gap is less likely to occur.

- The present invention provides an adhesive strength-enhancing film made of a base oxide film and a metal from Groups 1a to VIa of the periodic table of elements, on the edge portions forming the magnetic gap of a pair of cores made of polycrystalline ferrite. In a magnetic head in which a ferromagnetic metal thin film with high saturation magnetic flux density is provided parallel to the magnetic gap,
It is characterized in that the base oxide film has a thickness of 5 to 25 layers, and the adhesion-strengthening film has a thickness of 5 to 200 layers.

■ According to the above technical means, five base oxide films are applied to the edge portions of the pair of ferrite cores that form the magnetic gap.
~25 people, and then a ferromagnetic metal thin film is applied through 5 to 200 people, so that the metal forming the adhesion strength film becomes ferrite at the temperature during annealing and core bonding. It is possible to prevent the formation of a layer with deteriorated magnetic properties due to diffusion into the core, and to obtain sufficient adhesion of the film.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. The same reference numerals as in FIGS. 6 to 10 indicate the same parts, and the explanation thereof will be omitted.

The feature of the present invention is the above ferrite core 2a + 2
A base oxide film 12 is formed by 5 to 25 people between b and the metal thin film 5.
The adhesion-strengthening film 6 is formed to have a thickness of 5 to 200 layers.

Regarding the film thickness of the base oxide film 12, if the film thickness is increased by 25 Å or more, the base oxide film starts to exert an influence as a pseudo gap. Furthermore, the adhesion between the ferrite cores 2a, 2b and the metal thin film 5 also deteriorates, resulting in film peeling. Conversely, if the thickness of the base oxide film 12 is made thinner than 5λ,
The function of the base oxide film is lost, and more than half of the metal used for the adhesion strength film 6 and the O in the ferrite core are combined, forming a layer with deteriorated magnetic properties, resulting in a pseudo gap.

If the thickness of the adhesion-strengthening film is less than 5λ, there is a problem in the adhesion with the metal thin film. On the other hand, if there are more than 200 people, the amount of diffusion during heat treatment such as annealing or glass fusion will deteriorate the magnetic properties of the ferromagnetic metal thin film, making it impossible to obtain good magnetic head properties.

Figure 4 shows 100 base oxide films and 400 adhesive strength films.
Curve A shows the results of the example when used as a human.

It can be seen that the contour effect due to the pseudo gap causes a large waviness in the frequency characteristic of 1.5 dB, indicating that the pseudo gap is large.

In FIG. 5, curve B shows the results of the example with the base oxide film thickness and the adhesion-strengthening film thickness of the present invention. It can be seen that the waviness in the frequency characteristics due to the contour effect has been suppressed to a small 0.3 dB.

According to the present invention, a magnetic gap is formed on the top end surface of a core chip formed by bonding and integrating a pair of ferrite cores,
When a thin ferromagnetic metal film is provided on the edge of the core located in the magnetic gap via a base oxide film and an adhesion-strengthening film, the thickness of the base oxide film and the adhesion-strengthening film are optimized. As a result, the metal forming the adhesion strength film showed appropriate diffusion between the ferrite core and the ferromagnetic metal thin film without being affected by the magnetic deterioration layer, and a magnetic head with almost no contour effect was obtained. In addition, because the adhesion-strengthening film spreads less, it is possible to improve the yield loss caused by air bubbles in the gear hub and large gear gear defects, and to prevent deterioration of the magnetic properties of the ferromagnetic metal thin film itself, resulting in sufficiently high reliability in output characteristics. It is possible to obtain a magnetic head with high performance.

[Brief explanation of drawings]

1 and 2 are a perspective view and a plan view showing an embodiment of the magnetic head according to the present invention, and FIG. 4 and 5 are frequency-output level characteristic diagrams showing the results of the embodiment of the present invention. 6, 7, and 9 are a perspective view and a plan view showing a specific example of a conventional magnetic head, and FIG. 8 is an enlarged sectional view of a main part showing a portion near the magnetic gap of the magnetic head shown in FIG. FIG. 10 is an enlarged cross-sectional view of a main part of the magnetic head of FIG. 9 showing a portion near the magnetic gap. 2...Core chip, 2a+2b...Core, 5...Metal thin film, 6...Adhesion strengthening film, 8...Top end surface, 12...Diffusion prevention layer, g...Magnetic gap. Rod flash figure 111 return turbidity f [duration 1] β1-

Claims (1)

[Claims] A base oxide film and an additive made of a metal from Groups IVa to VIa of the periodic table of elements are formed on the edge portions forming a magnetic gap of a pair of cores made of polycrystalline ferrite, a ferromagnetic oxide. In a magnetic head in which a ferromagnetic metal thin film having a high saturation magnetic flux density is provided in parallel to the magnetic gap via an adhesion-strengthening film, the thickness of the base oxide film is 5 to 25 Å and the thickness of the adhesion-strengthening film is 1. A magnetic head characterized in that a magnetic head is formed with a thickness of 5 to 200 Å.