JPH0727613B2 - Magnetic head and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a magnetic head.

2. Description of the Related Art Conventionally, ferrite has been widely used as a core material for magnetic heads because of its good workability and wear resistance, but its saturation magnetic flux density B _S is 30 to 50% lower than that of alloy materials.
Therefore, when used in a high-density recording medium with a high coercive force that has recently appeared, magnetic saturation of the head core material becomes a problem. From such a viewpoint, various alloy materials are used as head gaps for the high-density recording medium. It is put to practical use as a so-called metal in-gap head arranged in the vicinity. With such a structure, it is put to practical use as a corresponding head for the high-density recording medium described above.

FIG. 2 shows a general tape sliding surface of this head. However, it has been found that the head output decreases when the head is run for a long time, for example, 100 hours or more. When the tape sliding surface of the head where the output is lowered is measured with a step gauge at the portion shown by the arrow in FIG. 2, the alloy material 2 drops by several hundred angstroms with respect to the ferrite 1, so-called uneven wear occurs. I understand. That is, it was found that the output was reduced due to spacing loss. Further, it is known that pseudo gap noise is generated due to the surface of soft magnetic ferrite and polycrystalline alloy magnetic material, which causes a problem because it deteriorates S / N.

As described above, the present invention solves the problem of uneven wear occurring in a metal in-gap head when a tape is run for a long time, resulting in a reduction in head output due to spacing loss, and further reduction of pseudo gap noise. An object is to provide a magnetic head that can be realized.

Means for Solving the Problems The present invention is a magnetic head comprising a magnetic core composed of ferrite and Sendust polycrystalline alloy magnetic material, and the Sendust polycrystalline alloy magnetic material is arranged near a head gap. The presence of a high oxygen concentration phase near the crystal grain boundaries of the polycrystalline alloy magnetic material by heat treatment in the atmosphere containing oxygen as an impurity gas at a temperature of 800 ° C or higher and 1000 ° C or lower in the manufacturing process As a result, the wear resistance is improved as compared with the polycrystalline alloy magnetic material of the parent phase, and as a result, the magnetic head improves uneven wear of the ferrite and the sendust polycrystalline alloy magnetic material.

Further, at this time, a diffusion preventing film is formed at the interface between the ferrite and the polycrystalline alloy magnetic material.

Effect The present invention improves the wear resistance of Sendust polycrystalline alloy, so that uneven wear between ferrite and Sendust polycrystalline alloy magnetic material does not occur even when the tape is run, and as a result, head output drop is small and stable. The obtained head output is obtained. Further, by forming a diffusion preventive film at the interface between the ferrite and the polycrystalline alloy magnetic material, the deterioration layer is prevented from occurring.

Examples Examples of the present invention will be described below.

Example 1 An example of the magnetic head of the present invention will be described with reference to FIG.

First, the ferrite material 4 is used as the substrate.

Next, using a Sendust polycrystalline alloy (Fe, Si, Al alloy) as a target, the inside of the vacuum chamber was evacuated to 5 × 10 ⁻⁷ Torr,
Ar gas was introduced to adjust the pressure to 1.5 × 10 ⁻³ Torr, a diffusion prevention film made of SiN5n was first formed on the ferrite material 4 as shown in FIG. 1 (b), and sendust alloy 5 was further sputtered.

Next, after processing the notch 6 as shown in FIG.
Treated in nitrogen containing 50 ppm oxygen at a temperature of ~ 1000 ° C for 20 hours.

Similarly, as shown in FIG. 3D, the notch 6 is filled with the glass 7, the winding window 8 is processed, the gap abutting surface is processed into a mirror surface with diamond paste, and a gap spacer material having a predetermined thickness is formed on the surface. Is sputtered (not shown) to complete the one-sided core for forming the gap.

The core thus completed was butt-joined with half halves of the core to form a gap as shown in FIG. A cutting head was completed from the pair of bars along the cutting line 10.

The head thus completed is mounted on a VTR deck, and the tape is run. After 200 hours, the head output and the results of uneven wear of ferrite and Sendust polycrystalline alloy are shown in Table 1 as shown by the arrows in FIG.

In addition, the head output is OdB of the head output immediately after running the tape.
And

Further, the heat treatment was carried out by processing the notch 6 as shown in FIG. 1 (c) and then treating it in nitrogen containing 50 ppm of oxygen at each temperature for 20 hours.

In the present invention, the heat treatment temperature is limited to 800 ℃ ~ 1000 ℃, the wear resistance of Sendust polycrystalline alloy is not sufficient at 800 ℃ or less, uneven wear occurs, and at 1000 ℃ or more of Sendust polycrystalline alloy itself. This is because the crystal characteristics become large and the magnetic properties are impaired, and mutual diffusion between Sendust polycrystalline alloy and ferrite occurs, which deteriorates the magnetic properties. Considering the above, the optimum temperature is around 900 ℃. Regarding the oxygen concentration, although the present invention has described about 50 ppm, 1 ppm to 500 ppm
It should be in the ppm range. If it is less than 1 ppm, oxygen is not sufficiently diffused, and if it is more than 500 ppm, surface oxidation occurs, which is not preferable. If the atmosphere contains oxygen at the above concentration, nitrogen, argon, hydrogen, vacuum, or the like may be appropriately selected. The sendust polycrystalline alloy composition is effective as long as it has a Fe-Si-Al composition as long as the magnetism is not impaired.

Further, since the portion having good wear resistance is, for example, about 100 μm at the most, even if the polishing amount is taken into consideration in the magnetic head in which the Sendust polycrystalline alloy magnetic material is arranged near the head gap as in the present application. Since the thickness of the Sendust polycrystalline alloy portion is 100 μm or less, the wear resistance of all Sendust polycrystalline alloy portions is good. Therefore, the heat treatment may be performed at any time basically, but it is desirable to perform the heat treatment after notching as in the present embodiment in consideration of the reaction with the glass and the looseness due to the heat treatment.

When the Sendust polycrystalline alloy portion of the head of the present invention was analyzed, it was found that a phase having a high oxygen concentration existed especially near the crystal grain boundaries. Further, when the surface was etched with oxygen plasma, grain boundaries were clearly shown and oxygen segregation was found.

Further, when the pseudo gap noise was measured, it was confirmed that the sample with the diffusion prevention film was improved by about 12 dB as compared with the sample without the diffusion prevention film. It was shown that the same effect can be obtained if the thickness of the diffusion barrier film is 50 A or more. If it is too thick, for example, 300 A or more will approach the shortest recording wavelength, which is not preferable.

Analysis of the effect of the diffusion preventive film by SIMS showed that there was almost no interdiffusion in any element in the sample with the diffusion preventive film. Large mutual diffusion was observed. This indicates that the diffusion prevention film may be a stable material that does not diffuse between itself and these magnetic materials, and diffusion between the ferrite and the alloy magnetic material.

Also, the same good result was obtained by alternately laminating the diffusion prevention film and the polycrystalline alloy film in multiple layers.

In this way, a stable head output can be obtained without lowering the head output.

Further, since this result is due to the thin segregation layer of oxygen generated at the grain boundaries of the alloy, it is presumed that other alloy magnetic materials also have such an oxidizing effect.

Further, the presence of a diffusion preventing film such as SiN in an amount of 300 A as an interface material in such a magnetic core can significantly improve the pseudo gap noise. It is needless to say that such a diffusion prevention film may be another stable fired film as long as it prevents mutual diffusion as described above. Therefore, according to the present invention, these effects are combined,
It is possible to provide a particularly excellent magnetic head that does not have uneven wear and does not have pseudo gap noise.

EFFECTS OF THE INVENTION As described above, according to the present invention, there is provided a magnetic core composed of ferrite and Sendust polycrystalline alloy magnetic material, and a magnetic core comprising the Sendust polycrystalline alloy magnetic material disposed in the vicinity of the head gap. The head, during the manufacturing process
Heat treatment is performed in an atmosphere containing oxygen as an impurity gas at a temperature of 800 ° C or more and 1000 ° C or less, and wear resistance of Sendust polycrystalline alloy is improved. Therefore, uneven wear between ferrite and Sendust polycrystalline alloy magnetic material runs on the tape. Even if it is made to occur, it hardly occurs, and as a result, stable head output can be obtained without reduction in head output.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a magnetic head in one embodiment of the present invention, and FIG. 2 is a front view showing a tape sliding surface of a conventional magnetic head. 1, 1 '... Ferrite, 2 2' ... Polycrystalline alloy magnetic material, 3 ... Gap, 4 ... Ferrite, 5 ... Sendust, 5n ... Diffusion prevention film, 6 ... Notch, 7 ... Glass, 8 ... Winding window, 9 ... Gap, 10 ... Cutting line.

Claims (4)

[Claims] 1. A polycrystalline alloy magnetic material comprising a magnetic core composed of a soft magnetic ferrite, a polycrystalline alloy magnetic material, and an interlayer material formed therebetween, the polycrystalline alloy magnetic material being disposed at least in the vicinity of the head gap. Near the crystal grain boundaries of the magnetic material,
A thin layer containing a high concentration of oxygen is formed without forming heterogeneous precipitates in the crystal grains, and a diffusion prevention film of 300 A or less is formed at least at the interface formed between the soft magnetic ferrite and the polycrystalline alloy magnetic material. A magnetic head characterized by being formed. 2. A method of manufacturing a magnetic head comprising a magnetic core composed of high-permeability ferrite and a polycrystalline alloy magnetic material, wherein the polycrystalline alloy magnetic material is arranged in the vicinity of a head gap. A method of manufacturing a magnetic head, characterized in that the method includes at least a step of forming a diffusion barrier film and a step of performing heat treatment at a temperature of 800 ° C. or higher and 1000 ° C. or lower in an atmosphere containing a small amount of oxygen as an impurity gas. 3. The magnetic head according to claim _1, wherein the polycrystalline alloy magnetic material is formed of an A ₁ FeSi alloy. 4. The method of manufacturing a magnetic head according to claim 2, wherein the polycrystalline alloy magnetic material is formed of an A ₁ FeSi alloy.