JPH077491B2 - Flying magnetic head - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a levitation type magnetic head used in a magnetic disk device, and more particularly to a composite type levitation type magnetic head using a thin film laminated core as a head core. It is a thing.

2. Description of the Related Art Generally, a floating magnetic head used in a magnetic disk device includes a slider and a head core, and is connected to an actuator of a device body via a leaf spring support mechanism.

Conventionally, such a flying type magnetic head is (1) a monolithic type manufactured by forming a slider with ferrite, forming a gap in a part of the slider, and then cutting and grinding the slider into a predetermined shape, and (2) A slider is formed of a non-magnetic material such as ceramics, and there is a ferrite-type composite type manufactured by welding a head core made of ferrite to the slider with glass. In recent years, high density recording has been achieved. Therefore, Fe-Si-, which has a high saturation magnetic flux density and excellent high-frequency characteristics of magnetic permeability,
A so-called MIG (Metal In Ga), in which magnetic thin films made of Al alloy (sendust), amorphous magnetic material, etc. are provided on both sides or one side of the ferrite head core with a gap between them,
The MIG composite type floating magnetic head, which uses a p) type head as the head core, has been attracting attention. As shown in FIG. 5, the ferrite type and MIG type composite type flying magnetic head has a head core 1 incorporated in a predetermined groove-shaped recess 3 of a ceramic slider 2 formed by cutting and grinding a single ceramic. It is formed by welding with the bonding glass 4.

In addition, a thin film laminated core that is used for VTR and can achieve high density recording and narrow track, that is, a magnetic thin film made of Fe-Si-Al alloy (sendust), amorphous magnetic material, etc. on a non-magnetic substrate. A thin-film laminated composite type flying magnetic head using a thin-film laminated core manufactured by laminating as a head core is provided, and an example thereof is shown in JP-A-62-18617. As shown in FIGS. 6 (A) to 6 (C), the head core 1 is assembled in a predetermined groove-shaped recess 3 of a ceramic slider 2 formed by cutting and grinding a single ceramic. It is manufactured by welding with bonded glass.

Problems to be solved by the invention.

In the process of researching and developing a composite-type floating magnetic head, the present inventors have found that in a conventional composite-type floating magnetic head, uneven wear occurs between the slider and the head core, or the surface of the bonding glass It was found that the surface became rough due to abrasion, and dust adhered to it, reducing CSS resistance.

That is, in the ferrite type and MIG type composite flying type magnetic heads, the slider and the head core are made of different materials, and the front gap side of the head core is thinned as shown in FIG. 5 in order to narrow the track of the gap. Therefore, the area of the bonded glass surface is large and the CSS resistance is reduced. Further, in the conventionally proposed thin-film laminated composite type floating magnetic head, no mention is made of the area of the surface of the bonded glass.

As a result of many studies and experiments to solve this problem, the inventors have formed a slider and a head core non-magnetic substrate of the same material in a composite type flying magnetic head using a thin film laminated core as a head core. And, the thermal expansion coefficient of the substrate material of the head core, the thermal expansion coefficient of the magnetic thin film material of the head core is substantially the same, by making the thickness of the bonding glass layer for bonding the head core and the slider extremely thin, It has been found that such a problem can be solved.

That is, by forming the slider and the head core substrate from the same material, uneven wear between the slider and the head core (head chip) is prevented, and moreover, the slider and the head core substrate have the same thermal expansion coefficient. As a result, the stress applied to the bonding glass layer for bonding the head core to the slider becomes extremely small, the deterioration of the glass after bonding can be prevented, and the reliability is improved.

Further, in the conventional ferrite type and MIG type composite type flying magnetic heads, the
As shown in the figure, only the front gap F _G is processed to define the track width W. However, in order to maintain the mechanical strength of the head core 1, the thickness T of the rear gap R _G is 150 to 200.
The thickness of the glass layer when the head core 1 is bonded to the slider is about 100 to 200 μm when the track width W is set to 20 μm or less.

On the other hand, the present inventors can drastically reduce the thickness of the glass layer when the head core is joined to the slider by defining the track width by the thickness of the magnetic alloy film and reinforcing both sides with ceramics. Therefore, it is possible to realize a reliable composite head as a whole by reducing the thickness of this bonding glass layer to 20 μm or less, further 10 μm or less, while ensuring reliability without deteriorating the glass after bonding. Found.

In addition, since the bonding glass layer could be made extremely thin in this way, the rough surface area of the glass layer with weak mechanical strength was reduced, and the amount of dust adhering to the surface was also significantly reduced, thus improving the CSS resistance. It turned out that it can improve the sex.

Further, by making the coefficient of thermal expansion of the head core substrate substantially the same as the coefficient of thermal expansion of the magnetic material of the head core, it is possible to reduce the stress applied to the magnetic material and prevent deterioration of the magnetic characteristics of the head.

The present invention has been made based on such novel findings.

Therefore, an object of the present invention is to eliminate uneven wear between the slider and the non-magnetic substrate of the head core, reduce the surface area of the bonding glass layer, further reduce the amount of dust attached thereon, and improve the CSS resistance. It is an object of the present invention to provide a composite-type flying magnetic head using a thin film laminated core as a head core, in which the stress applied to the magnetic material is reduced and the head characteristics are improved.

Means for Solving the Problems The above object can be achieved by a composite type flying type magnetic head according to the present invention. In summary, the present invention is a floating magnetic head configured by integrally bonding a head core formed by laminating magnetic thin films on a non-magnetic substrate to a recess formed in a slider via a bonding glass layer. At
A bonding glass for bonding the head core and the slider, in which the head core substrate and the slider are made of the same material, and the thermal expansion coefficient of the head core substrate and the thermal expansion coefficient of the magnetic thin film are substantially the same. Layer thickness 20μ
The flying magnetic head is characterized in that it is set to m or less. Preferably, the substrate of the head core and the slider are made of a ceramic material represented by Co _x Ni _2-x O ₂ (where 0.2 ≦ X ≦ 1.8), and the magnetic thin film is Fe—Si—Al.
Made of alloy.

Furthermore, the ceramic material for producing the substrate of the head core and the slider has a basic composition of CoO and NiO,
At least 1 selected from MnO, TiO ₂ , Al ₂ O ₃ and CaO
The seeds can be added in an amount of 0.1 to 5% by weight, and also 1 to 5% by weight of Y ₂ O ₃ , 0.1 to 1% by weight of TiN and 0.3 to 2% by weight of B.
_At least one of ₂ O ₃ may be added.
Furthermore, the substrate of the head core and the slider are
A mixed ceramic having a composition consisting of O, CaO, CoO, and NiO, each containing MgO and CaO in an amount of 30 mol% or less, and the balance being Co _x Ni _2-x O ₂ (however, 0.2 ≦ X ≦ 1.8) Will be
It is also possible to make it with a ceramic material having a rock salt type structure.

EXAMPLE Next, the floating magnetic head according to the present invention will be described in more detail with reference to the drawings.

Referring to FIG. 4, an embodiment of a composite type flying magnetic head constructed in accordance with the present invention is illustrated. In this embodiment, the floating magnetic head is provided with a slider 2 and a head core 1 as in the conventional case, and is connected to an actuator (not shown) of the magnetic disk device body via a leaf spring support mechanism 5.

Next, with reference to FIG. 3, an embodiment of a method of manufacturing a thin film laminated core used as the head core 1 and configured by laminating magnetic thin films on a non-magnetic substrate will be described. As the magnetic thin film, an Fe-Si-Al alloy magnetic body or an amorphous magnetic body is used, but in this embodiment, an Fe-Si-Al alloy magnetic body is used.

First, the non-magnetic substrate 11 is prepared (FIG. 3 (A)), and the Fe—Si—Al alloy film 12 is formed on the substrate 11 by sputtering to have a film thickness of 1 to 20 μm. Next, the non-magnetic insulating film 13 is formed on the Fe-Si-Al alloy film 12 to have a film thickness of 0.03 to 0.5 μm by the sputtering method (FIG. 3 (B)). As the nonmagnetic insulating film 13, SiO ₂ , Al ₂ O ₃ or the like is used.

By repeating the above process, the Fe-Si-Al alloy film 12 and the non-magnetic insulating film
The alloy magnetic thin film 14 is deposited on the substrate 11 as shown in FIG. 3 (C), and the outermost layer of the alloy magnetic thin film 14 is the Fe-Si-Al alloy film 12 Is preferred. At this time, the total thickness (t) of the alloy magnetic thin film 14 is preferably 30 μm or less from the economical point of view.

Then, the laminated glass 15 on the alloy magnetic thin film 14 has a film thickness of 0.05 to
It is formed by a sputtering method or the like at 1.0 μm (FIG. 3 (D)), and the other non-magnetic substrate 16 made of the same material as the previous substrate 11 is bonded onto the laminated glass 15 to make it magnetic. The core block 17 is produced (FIG. 3 (E)). As the laminated glass 15, SiO ₂ -Al ₂ O ₃ -Na ₂ O type glass or SiO _2-
B ₂ O ₃ —Na ₂ O based glass is suitable.

The magnetic core block 17 manufactured in this way has a third
As shown in FIG. 4F, the laminated half-blocks 18 and 19 are formed by cutting the laminated sheets in the thickness direction.

Then, as shown in FIG. 2, after forming the winding groove 20 in at least one of the core half bodies, in this embodiment, the core half body 18, the abutting surfaces 18a of both core half body blocks 18 and 19, 19a is polished and a non-magnetic gap spacer 21 such as SiO ₂ is polished on the surface.
Is formed by a method such as a sputtering method (FIG. 3 (F)), and then, as shown in FIG. 2, both core half blocks 18 and 19 are glass at the joint surfaces 18a and 19a. The head core 1 composed of the thin film laminated core that is bonded is obtained.

As shown in FIGS. 1 and 2, the head core 1 manufactured in this way has a bonding glass layer 4 (4a, 4b, 4c) in the recess 3 of the slider 2 manufactured in a predetermined shape and size. )
And a composite type floating magnetic head are formed.

Here, according to the present invention, in the floating magnetic head having the above-described configuration, the non-magnetic substrates 11 and 16 of the head core 1 and the slider 2 are made of the same material, and the substrate 1 of the head core 1 is made.
The thermal expansion coefficients of 1, 16 and the alloy magnetic thin film 14, that is, the thermal expansion coefficient of sendust are made substantially the same, and the bonding glass layer 4
The thickness is set to 20 μm or less.

Generally, the thermal expansion coefficient (α) of Fe-Si-Al alloy magnetic material is 13
Since it is 5 to 150 × 10 ⁻⁷ / ° C., the substrate 11 of the head core 1,
A material having such a coefficient of thermal expansion is selected for 16.

Al ₂ O ₃ which was previously considered to be the optimum slider material
-The thermal expansion coefficient (α) of TiC-based ceramic materials and CaTiO ₃ ceramic materials is 75-80 × 10 ^-7 /
C. and 110 to 115.times.10.sup.- ⁷ / .degree. C., which has a large difference in coefficient of thermal expansion from the sendust thin film, and cannot be used in this example.

The present inventors have studied to develop a material having substantially the same thermal expansion coefficient as the sendust thin film, and as a result, Co _x Ni _2-x
It was found that an oxide having a composition of O ₂ (however, 0.2 ≦ X ≦ 1.8) is effective. Within this composition range, the coefficient of thermal expansion is 12
It can be easily adjusted within the range of 8 to 150 × 10 ^-7 / ° C, and the hardness (Vickers hardness) is 550 to 600, which is close to the physical properties of Sendust. Also, as will be described later, according to the test results using the dummy slider, the CS resistance of the ceramic itself is
The S property was as good as that of a conventional ceramic slider material such as CaTiO ₃ .

Moreover, when the additive material is also examined, it is effective to add 0.1 to 5% by weight of at least one selected from MnO, TiO ₂ , Al ₂ O ₃ and CaO based on the above composition as a basic composition. It turned out that That is, MnO promotes sinterability, TiO ₂ and CaO bring about an increase in hardness, and Al ₂ O ₃ has an effect of suppressing grain growth.

Further, when Y ₂ O ₃ is added in an amount of 1 to 5% by weight, it is effective in suppressing grain growth, and when 0.1 to 1% by weight of TiN is added,
This results in an increase in hardness and, when 0.3 to ₂ % by weight of B ₂ O ₃ is added, promotes sinter formation.

With these additives, the hardness becomes 600 to 700, which is closer to the value of Sendust, which is preferable.

Furthermore, mixed ceramics of Co _x Ni _2-x O ₂ (however, 0.2 ≦ X ≦ 1.8) and other oxides are also examined, and MgO, CaO, Co
In mixed ceramics composed of O and NiO, Mg
O and CaO content of less than 30 mol% each and the balance Co
_{It has been found that x} Ni _{2 -x} O ₂ (provided that 0.2 ≦ X ≦ 1.8) can be suitably used in the present invention even when it has a rock salt type structure.

MgO and CaO are effective because they have the effect of promoting sintering, increase the hardness, and have the same coefficient of thermal expansion as CoO and NiO. Outside the above composition range, the thermal expansion coefficient is remarkably reduced,
It is not desirable because it causes segregation and lowers the density.

The inventors of the present invention produced a floating magnetic head using the above-mentioned ceramics having a basic composition of CoO and NiO as a substrate of the head core and a slider, and found that the thermal matching between the members was extremely good, and therefore the head core ( The stress applied to the bonding glass layer 4 for bonding the head chip) to the slider is extremely small, the deterioration of the glass after bonding can be prevented, and the reliability is improved.

Further, in the conventional ferrite type and MIG type composite type flying magnetic heads, the
As described above in connection with the figure, the front gap F _G
Only the track width W is processed to define the track width W, but in order to maintain the mechanical strength of the head core 1, the thickness T of the rear gap portion R _G needs to be about 150 to 200 μm. For example, the track width W is 20 μm. In the following case, the thickness of the glass layer when the head core is bonded to the slider is about 100 to 200 μm.

On the other hand, in the head core according to the present invention, the track width can be defined by the thickness of the magnetic alloy film, and both ends thereof are reinforced with ceramics, so that the thickness of the glass layer when the head core is bonded to the slider can be significantly reduced. it can.

In this way, without degrading the glass after bonding,
By ensuring the reliability and setting the thickness of the bonding glass layer to 20 μm or less, further 10 μm or less, a reliable composite head can be realized as a whole.

The lower limit of the thickness of the bonding glass layer is restricted by the fitting accuracy of the head core and the slider, and is 2 in the current technical level.
Approximately 3 μm.

As described above, according to the present invention, the bonding glass layer 4 has a thickness of 10 μm.
By the following, the rough surface area of the bonding glass layer having weak mechanical strength can be reduced, the amount of dust attached to the area can be greatly reduced, and the CSS resistance can be improved. Regarding this point, FIG. 8 and FIG.
A more detailed description will be given with reference to the drawings.

Next, one example of the ceramic material that can be used in the present invention will be specifically described below.

Example 1 CoO and NiO were used as raw materials and adjusted to have a CoNiO ₂ composition and mixed. This was calcined in N ₂ at 1000 ° C., and then pulverized with an ethanol wet ball mill for 22 hours. After crushing this crushed powder into CIP, 1 in O ₂
Sintered at 350 ° C.

The HIP treatment was performed at 1280 ° C. and 1000 Kg / cm ² for 1 hour.

The physical properties of the sintered body according to this example were as follows.

Density 6.5g / cm ³ Hardness (Hv) 700 Bending strength 30Kg / mm ² Average crystal grain size 6.8μm Thermal expansion coefficient 136 × 10 ^-7 / ℃ The coefficient of thermal expansion is determined by the composition of the material.
The characteristics of 128 to 150 × 10 ^-7 / ° C were exhibited.

The ceramic material thus produced was used for the substrate of the head core and the slider to produce a flying magnetic head.

Since the groove for forming the recess 3 of the slider 2 cannot be perfectly square, the end surface 1a of the head core 1 has a chamfer of 10 to 20 μm as shown in FIG. I went.

Table 1 shows the test results of the materials of the flying magnetic head and the dummy slider manufactured by using the material of this example in comparison with the conventional example using CaTiO ₃ .

From Table 1, the flying magnetic head of the present invention can reduce the amount of dust attached to the glass layer region because the bonding glass layer 4 can be set to 20 μm or less as described above. The CSS resistance was also improved.

Also, the CSS resistance of the ceramic material produced in this way
Also, according to the test results with the dummy slider, the CSS resistance was about the same as the result of the conventional CaTiO ₂ tested with the dummy slider. As a result, the Co
It was found that the ceramics based on O and NiO have good CSS resistance even in the material itself.

A similar test was conducted on a ceramic having a basic composition of MnO and NiO using a dummy lidar, but it was found that adhesion was generated at CSS10000 times and it was unsuitable as a slider material.

For the measurement of CSS resistance, a disc coated with a carbon film having a diameter of 3.5 inches was used.
The time cycle was such that the speed was increased to 00 rpm, held at 3600 rpm for 1 second, then reduced to 0 rpm in 4 seconds, stopped for 1 second, and restarted.

Next, the thickness of the bonding glass layer 4 was changed and the CSS resistance was measured. Fig. 8 shows an example of changes in the dynamic friction coefficient (μ) with respect to the number of CSS cycles. For example, the coefficient of dynamic friction is 0.5 and
The number of CSS cycles when the value becomes 0.6 is 10 for the thickness of the bonding glass layer.
2.1 x 10 ³ and 4.9 x 10 ^{3 for} 5 μm, respectively
If the thickness of the bonding glass layer is 15 μm,
It is 6.2 × 10 ⁴ and 8.4 × 10 ⁴ , respectively, and it can be seen that the CSS resistance can be improved by setting the bonding glass layer thickness to 20 μm or less.

Further, FIG. 9 shows the number of CSS cycles at which the dynamic friction coefficient becomes 0.5 and 0.6 at each bonded glass layer thickness. It can be seen from FIG. 9 that the thickness of the bonding glass layer must be 20 μm or less in order to set the CSS cycle numbers at which the dynamic friction coefficient becomes 0.5 and 0.6 to 50,000 and 70,000 times or more, respectively.

In the above-described embodiment, the head core is made of the sendust magnetic thin film, but an amorphous magnetic thin film can also be used. In this case, for example, when an amorphous thin film such as a rare earth element-Co alloy magnetic body is used, the thermal expansion coefficient (α) of the magnetic thin film is 110 to 120 ×
Since it is 10 ⁻⁷ / ° C., a material having such a thermal expansion coefficient is selected as the material of the substrates 11 and 16 of the head core 1 and the slider 2. Mg as such a ceramic material
Examples include O-based ceramics.

EFFECTS OF THE INVENTION The flying magnetic head according to the present invention configured as described above causes uneven wear between the slider and the non-magnetic substrate of the head core, reduces the surface area of the bonding glass layer, and further There is an effect that dust is extremely rarely adhered, stress applied to the magnetic material is reduced, and CSS resistance and head characteristics can be improved.

[Brief description of drawings]

FIG. 1 is a partially enlarged detailed view of a composite type flying type magnetic head according to the present invention. FIG. 2 is a perspective view of a composite type flying magnetic head according to the present invention. FIG. 3 is a process drawing showing the method of manufacturing the head core. FIG. 4 is a perspective view showing the overall structure of a composite type flying type magnetic head according to the present invention. FIG. 5 is a perspective view of a conventional ferrite type composite type flying type magnetic head. FIG. 6 (A) is a perspective view of a conventionally proposed thin film laminated composite type floating magnetic head.
FIG. 6B is a perspective view showing the ceramic slider, and FIG. 6C is a perspective view showing the head core. FIG. 7 is a perspective view of a conventional ferrite type composite type head core (head chip). FIG. 8 is a graph showing the relationship between the CSS cycle number and the dynamic friction coefficient. FIG. 9 is a graph showing the relationship between the thickness of the bonding glass layer and the number of CSS cycles. 1: Head core 2: Slider 3: Groove-shaped recess of slide 4: Bonding glass layer 14: Multilayer magnetic thin film

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-64-50217 (JP, A) JP-A-62-22411 (JP, A) JP-A-61-192005 (JP, A)

Claims (5)

[Claims] 1. A flying magnetic head constructed by integrally bonding a head core formed by laminating magnetic thin films on a non-magnetic substrate to a recess formed in a slider via a bonding glass layer. The head core substrate and the slider are made of the same material, and the thermal expansion coefficient of the head core substrate and the thermal expansion coefficient of the magnetic thin film are substantially the same,
A flying magnetic head characterized in that a thickness of a bonding glass layer for bonding the head core and the slider is set to 20 μm or less. 2. The head core substrate and the slider are made of a ceramic material represented by Co _x Ni _2-x O ₂ (where 0.2 ≦ X ≦ 1.8), and the magnetic thin film is Fe-Si. The flying magnetic head according to claim 1, wherein the flying magnetic head is made of an -Al alloy. 3. The head core substrate and the slider have a basic composition of CoO and NiO, and 0.1 to 5% by weight of at least one selected from MnO, TiO ₂ , Al ₂ O ₃ and CaO.
The flying magnetic head according to claim 2, wherein the flying magnetic head is made of an added ceramic material. 4. The head core substrate and the slider have a basic composition of CoO and NiO of 1 to 5 wt% Y.
The floating mold according to claim 2, which is made of a ceramic material to which at least one of ₂ O ₃ , 0.1 to 1 wt% TiN and 0.3 to ₂ wt% B ₂ O ₃ is added. Magnetic head. 5. The head core substrate and the slider are mixed ceramics having a composition of MgO, CaO, CoO and NiO, each containing MgO and CaO in an amount of 30 mol% or less, and the balance being Co _x. The flying magnetic head according to claim 2, wherein the flying magnetic head is made of a ceramic material having a rock-salt type structure, wherein Ni _2−x O ₂ (where 0.2 ≦ X ≦ 1.8).