JPH0782615B2 - Substrate material for magnetic head and magnetic head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a nonmagnetic substrate material for a magnetic head and a magnetic head for depositing a soft magnetic metal film.

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 it is used for 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, as a corresponding head for the high-density recording medium, sendust or an amorphous alloy is used. A material is provided for the head core material. Barium titanate BaTiO ₃ and calcium titanate CaTi are used as substrate materials for such alloy materials.
Ceramic materials such as O ₃ have been proposed. However, in the case of a ceramic substrate composed of such a material, the metal film peels off due to the difference in the coefficient of thermal expansion during film formation such as vapor deposition or sputtering of a metal magnetic material such as sendust or an amorphous alloy film. was there. With respect to such a substrate material, LiO, SiO _{2 which} has a thermal expansion coefficient almost equal to that of the alloy film and crystallizes by exposure as a non-magnetic substrate material.
A photosensitive crystallized glass containing as a main component is used.

On the other hand, when the above-mentioned alloy material is used as the core material of the magnetic head, the resistivity of the material itself is as low as 70 to 120 μΩcm, so there is a large loss due to eddy currents in the high frequency range, so improvement is usually made by a laminated structure. There is. In an audio head, the track width is as large as several hundred μ and the frequency range is low, so the core thickness per sheet is as thick as 200-300 μ, and so-called adhesive such as epoxy resin is used for lamination and gap formation. Is used. However, when it comes to video, computer, and measuring heads, the track width is very small (for example, tens of μ) and the gap length is very short (for example, 0.3 μ or less). Is difficult to maintain. Since the track width is small and the frequency range used is as high as several MHz, the core thickness per sheet is preferably 10 μm or less. Such a thickness is difficult with the current processing technology, and even with ribbon amorphous or ribbon sendust with a thickness of 20μ or less due to the ultra rapid cooling method.
Therefore, from the above viewpoint, a method of thinning an amorphous alloy or sendust alloy, which is a magnetic material, by a sputtering method or a vapor deposition method is adopted. According to these methods, it is possible to easily obtain cores with a thickness of 10 μm or less per sheet, and it is possible to stack magnetic materials and interlayer insulating materials alternately, and the adhesion strength between each material is also strong. It is possible to maintain the high precision gap. It is known that SiO ₂ is used as the interlayer insulating material at this time. (Trans.IECE'74 / 9 VOL.57-C No.9, IEICE Technical Committee Material MAG82-36). It is also known to use SiO ₂ as the gap spacer material.

However, the crystallized glass has poor machinability, and the cutting speed with a diamond cutter is, for example, 1/5 to 1/10 that of a ferrite material, which is not suitable for mass production. Also, when a magnetic head was manufactured using crystallized glass as the substrate material and SiO ₂ as the interlayer insulating material and the gap spacer material, and a tape running test was carried out in various environments using a commercially available coated metal tape, particularly low humidity. Environment (eg 20
A large drop in head output was observed at 10 ° C and 10% RH. Observing the tape sliding surface of the head with reduced output, it was found that there were deposits selectively on the glass substrate, interlayer insulation material, and gap spacer material. Met. When this deposit was subjected to Auger analysis, the adhering component was the magnetic material in the tape medium, and the value obtained by the step gauge and the depth obtained by Auger analysis were in agreement.

From the above results, when the coated metal tape is run in a low humidity environment, the magnetic material in the metal tape selectively adheres to the glass substrate part, the interlayer insulating material, and the gap spacer material part, and the adhered material rises up. It was also found that the head output is reduced due to the spacing loss between the head and tape.

On the other hand, when the number of laminated layers was increased, the magnetic permeability (μ ') tended to decrease even though the thickness of the magnetic material was the same. This means that the magnetostriction constant (λs) of the magnetic material is not completely zero, but it is also due to the fact that the thermal expansion coefficient (α) of the magnetic material and SiO ₂ is one digit or more.

Means for Solving the Problems A magnetic head substrate, an interlayer insulating material, or a gap spacer material is mainly composed of CoO—MO—XO ₂ (where M = Ni or
At least one of Mn and at least one of X = Ti, Zr or Hf).

Since the substrate has the same coefficient of thermal expansion as the magnetic metal material,
A magnetic film can be produced using a thin film production system, and Mn-Zn
It can be machined close to ferrite, and a magnetic head using these as a substrate, interlayer insulating material, and gap spacer material does not adhere to the tape medium, so a stable head output can be obtained. In addition, the coefficient of thermal expansion of the interlayer insulating material
Since it is larger than SiO ₂ by one digit or more and is closer to a metallic magnetic material, the influence of the stress corresponding to the magnetic material is reduced especially when the number of laminated layers is large, and the deterioration of the magnetic head characteristics is less likely to occur.

Example 1 CoO, NiO, MnO and TiO ₂ were weighed so that the composition shown in Table 1 was obtained, mixed with a ball mill for 16 hours, and then dry water was added as a binder, and a die was used with a hydraulic press to obtain 500 kg / cm
After being molded at ² , it was hot pressed and sintered in air at 1300 ° C. for 2 hours under a pressure of 300 kg / cm ² . The coefficient of thermal expansion of the sintered body thus obtained and the load current value of the spindle motor when the sintered body of the same size was cut with a diamond cutter were standardized to 1 when the Mn-Zn ferrite of the same size was cut. Shown as cutting load. Both materials are smaller than crystallized glass, easy to cut, and exhibit a workability close to that of ferrite. Although Ti is shown as X in the examples, almost the same results are obtained for Zr and Hf. However, the thermal expansion coefficients of Zr and Hf tend to be slightly smaller.

Embodiment 2 An embodiment of the present invention will be described with reference to FIGS. 1 and 2.
The sintered body having the composition shown in Table 1 was mirror-polished as a substrate material and thoroughly washed to form a substrate 1 in a vacuum chamber with a pressure of 3 × 10 ⁻⁷ Torr.
After evacuation to Ar, Ar gas was introduced to 2 × 10 ⁻² Tor, and Co ₈₁ Nb ₁₃ Zr ₆ was sputtered as a target composition to form a 10 μ amorphous alloy film 2a.

Next, using SiO ₂ as an interlayer insulating material and a sintered body having the composition shown in Table 1 as a target, Ar pressure of 4 × was applied on the amorphous alloy film 2a.
Sputtering was performed at 10 ^-2 Torr to produce an interlayer insulating material 3a having a thickness of about 1000 Å. Similarly, the amorphous alloy film and the interlayer insulating material were alternately sputtered with 2b, 3b and 2c to obtain a block of three layers of the amorphous alloy film. On the other hand, a substrate 5 made of the same material as the substrate 1 was adhered to the laminated glass layer 4 to obtain a laminated core.

Next, after processing the winding window 6 on the gap abutting surface, the abutting surface is processed into a mirror surface with diamond paste, and the same material as the interlayer insulating material is sputtered on this surface as a gap spacer material to a predetermined thickness to form a gap. One side for forming is completed. Exactly the same structure as this block 1 '~
The laminated core halves made of 5 ′ were butted against each other, and a gap was formed by the bonding glass 7. A predetermined head was cut out from this pair of bars to complete a head. As a comparative example, a commercially available crystallized glass substrate was used, and an interlayer insulating material and a head using SiO ₂ as a gap spacer material were also manufactured.

These heads were thrust into a video tape recorder (head tape relative speed 3.8 m / sec), and tape running tests were performed in various environments using commercially available coated metal tapes. Using a crystallized glass substrate, SiO ₂ In the head composed of the interlayer insulating material or the gap material, a large decrease in the head output was observed in a low humidity environment, while in the head composed of the interlayer insulating material or the gap material using the material of the present invention as the substrate. , Stable output was obtained under all environments.

Incidentally material of the present invention, namely the substrate material, the interlayer insulation or gap material to the CoO-MO-XO ₂ (at least one where M = Ni or Mn, X = Ti, at least one of Zr or Hf) main component However, both materials have the same effect. Table 2 shows the head output of the head of the present invention at 23 ° C. and 10% relative humidity and the head output of the conventional head for reference.
The head output is shown as 0 (dB) at 23 ° C and 70% relative humidity.

Example 3 Next, non-magnetic stainless steel was used as a substrate, and a sendust alloy (Fe, Si, Al alloy) was used as a target, and 5 × 10 5 in a vacuum chamber was used.
After evacuating to ^-7 Torr, Ar gas is introduced and 1.5 × 10 ^-3 Torr
And sputtered. Next, using the interlayer insulating material as a target, sputtering was performed on the sendust film at an Ar pressure of 4 × 10 ^-2 TOrr to produce an interlayer insulating material of about 1000 Å.

Similarly, a sendust alloy film and an interlayer insulating material were alternately laminated to form a multilayer sendust film.

The permeability of 1 mOe at 1 KHz of the film thus obtained is
Shown on the table.

The magnetic permeability in the table is shown with respect to the thickness of the magnetic material, that is, ignoring the interlayer insulating material.

In the present invention, CoO is limited to 25 to 80 mol%, MO is limited to 0 to 50 mol%, and XO ₂ is limited to 5 to 20 mol%. This is because if the amorphous alloy is vapor-deposited by a sputtering apparatus or the like, the alloy film may peel off. Also, the thermal expansion coefficient of the interlayer insulating material is closer to that of the alloy film. A few percent
Incorporation of other elements at internal levels is permissible provided that the coefficient of thermal expansion and machinability are not compromised. The amorphous alloy film is a metal-metal type Co-M (M is N
b, Ti, Ta, Zr, W, etc.) and Co-M ₁ -M ₂ (M ₁ , M ₂ are the metal elements shown by M above), as well as Si, B, C, P-containing metals. -There is no particular inconvenience for metalloids. Although the magnetic head having the sandwich structure in which the head core is sandwiched between the substrates has been described in the above embodiments, the magnetic head does not include the substrate on the tape sliding surface, that is, the tape sliding surface is entirely made of a magnetic material having a multilayer structure. However, it has the same effect. There is no particular limitation on the composition of the sendust alloy, and an Fe-Si-Al alloy composition is effective. This is also true for Permalloy (iron-nickel alloy), which is an alloy magnetic material, because the effect of magnetic permeability on magnetostriction is large, and the same effect can be expected.

EFFECTS OF THE INVENTION The substrate material of the present invention has better machinability than conventional crystallized glass and is therefore easy to process, and a magnetic head in which this is used as a substrate material and an interlayer insulating material or a gearup material is Since the expansion coefficient is almost the same as that of the amorphous alloy, there is no fear that the alloy film will be peeled off even if it is vapor-deposited by a sputtering apparatus or the like. In addition, the magnetic material component in the tape does not adhere to the tape running in a wide range of practically used environments, so that a stable output can be obtained and a reliable magnetic head can be supplied.

[Brief description of drawings]

FIG. 1 is a front view showing a tape sliding surface of a magnetic head in one embodiment of the present invention, and FIG. 2 is a side view thereof. 1, 1 '... Substrate, 2a, 2a' ... Amorphous alloy, 3a, 3a '
... Insulating material 4, 4 '... Adhesive glass layer 5, 5'
…… Substrate, 6 …… Winding window, 7 …… Adhesive glass, 8 ……
gap.

Claims (5)

[Claims] 1. CoO of 25 to 80 mol%, MO of 0 to 50 mol%, X
A substrate material for a magnetic head, containing O _{2 in an amount} of 5 to 20 mol%. (However, M is at least one of Ni and Mn, X
Is at least one of Ti, Zr or Hf). 2. The magnetic head substrate material according to claim 1, wherein the thermal expansion coefficient is 100 to 125 × 10 ⁻⁷ / ° C. 3. A tape sliding surface of a head chip, which is in contact with at least a magnetic tape, is made of a multi-layer magnetic material, and the multi-layer interlayer insulating material or gap spacer material contains 25 to 80 mol% of CoO and MO. 0 to 50 mol% and XO ₂ to 5
20 mol% (where M is at least one of Ni and Mn, X is
A magnetic head comprising a material containing at least one of Ti, Zr and Hf. 4. The magnetic head according to claim 3, wherein the magnetic material having a multilayer structure is made of an amorphous alloy. 5. A magnetic head according to claim 3, wherein the multi-layered magnetic body is made of Sendust alloy or Permalloy alloy.