JPH0520657A - Floating type composite magnetic head - Google Patents

Abstract

PURPOSE:To prevent the generation of cracks and to improve head characteristics by decreasing the stress concentration near both ends of the track of nonmagnetic layers constituting a magnetic gap. CONSTITUTION:A magnetic head core constituted by forming magnetic metallic thin films 23, 23' and the magnetic gap on the opposite surfaces of a pair of ferrite core pieces consisting of an Mn-Zn single crystal is embedded and fixed into the slit provided on the air bearing of a nonmagnetic slider, by which the floating type composite magnetic head of a composite type is formed. The nonmagnetic layer constituting the magnetic gap is made of the composite structure consisting of the nonmagnetic layers of at least SiO2 films 22, 22 and glass film 23 near both ends of the track width from the central part and the nonmagnetic layers 24 without contg. the SiO2 films near both ends of the track width.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a magnetic disk device, and the Mn--Zn single crystal ferrite core piece is provided with an opposing surface,
The present invention relates to a composite floating magnetic head using a magnetic head core having a magnetic gap formed of a non-magnetic layer including a SiO ₂ film.

[0002]

2. Description of the Related Art As a floating magnetic head used in a magnetic disk device, a monolithic magnetic head using Mn--Zn polycrystalline ferrite or the like for a slider and CaTiO.
A non-magnetic material such as _{3 is} used as a slider, and a magnetic head core made of Mn-Zn single crystal ferrite or the like is used as a slider.
There is a composite type magnetic head held in the slit. Mn-Zn ferrite has a saturation magnetic flux density of 5000 G.
In a magnetic head core composed only of ferrite, it is 1000 to 1 to cope with high frequency and high density.
It is impossible to generate sufficient magnetic field strength to saturate a magnetic disk having a high coercive force of 500 Oe. For this reason, a composite-type floating magnetic head using a composite magnetic head in which a metal magnetic thin film is formed on at least one opposing surface of a Mn-Zn single crystal ferrite core piece has also been used. 7 and 8 are perspective views showing the basic structure of a composite magnetic head core which constitutes a flying composite magnetic head used in a magnetic disk device for high frequency and high density recording and its electromagnetic converter. In FIG. 7, reference numeral 71 is a floating magnetic head, and 72 is a slider made of a non-magnetic material such as CaTiO ₃ . The magnetic head core 73 is fixed and held by a mold glass 75 in a slit 74 formed in an air bearing 76. In FIG. 8, 8
Denoted at 82 'are a pair of high magnetic permeability Mn-Zn single crystal ferrite core pieces constituting the magnetic head core 81.
Is a metal magnetic thin film having a high saturation magnetic flux density formed on the opposing surface of one of the core pieces, 84 is a non-magnetic material that serves as a magnetic gap for joining the pair of core pieces, and 85 is a bonding that reinforces the joining. It is glass.

[0003]

Since the areal recording density is increased, the track recording density and the linear recording density are increased,
In order to cope with this, the magnetic head is required to have a narrow track and a small magnetic gap length, as well as strict dimensional accuracy with respect to the nominal dimension. To ensure the accuracy of the magnetic gap length, or compression bonding by forming a SiO ₂ as the magnetic gap member, both core pieces depositing the SiO ₂ equal to bonded via the glass film, in the SiO ₂ film A method of defining the gap length is used. In FIG. 9, metal magnetic thin films 95 and 95 ′ are formed on both of the single crystal ferrite core pieces 91 and 91 ′, and the SiO ₂ film 93, the glass film 92 and the SiO ₂ film 93 ′ are formed.
FIG. 6 is a diagram showing the vicinity of a gap of a magnetic head core having a magnetic gap consisting of Thermal expansion coefficient in the vicinity 400 to 550 ° C. of the elements constituting the vicinity of the magnetic gap is a ferrite core pieces 70 × 10 ⁷ / ° C. before and after the magnetic metal thin film 140 × in Fe-Al-Si based thin film 10- ⁷ / ° C
Longitudinal, mode - Rudogarasu glass film 100 × 10- ⁷ / ℃
While front and rear, the thermal expansion coefficient of the SiO ₂ film 5 × 10- ⁷
Very small, around / ° C. Due to such a large difference in the coefficient of thermal expansion, a large tensile stress acts on the SiO ₂ film and the glass film near both ends on the track width side in the process of fixing the magnetic head core embedded in the slit of the slider with the mold glass. . Especially for glass film, 8-10kg / c
There is a problem that a large tensile stress exceeding the fracture toughness value of m ² acts, cracks are easily generated in the magnetic gap starting from the glass film, and the head characteristics are deteriorated.

[0004]

In a composite-type floating composite magnetic head of the present invention, a pair of Mn-Zn single crystal ferrite core pieces constituting a magnetic head core are arranged so as to face each other, and at least one of the core pieces is arranged. Is a composite type levitation type magnetic head in which a magnetic metal thin film is formed on opposite surfaces of the magnetic head core, and a magnetic head core having a magnetic gap is embedded and fixed in a slit provided in an air bearing of a non-magnetic slider. The non-magnetic layer includes a non-magnetic layer formed of a SiO ₂ film and a glass film from the center of the track to the vicinity of both ends on the track width side, and a non-magnetic layer containing substantially no SiO ₂ film near both ends on the track width side. It has a composite structure consisting of The present invention is more effective especially for a composite type magnetic head core of both films in which a metal magnetic thin film is formed on the facing surfaces of both core pieces of a Mn—Zn single crystal ferrite core piece. The nonmagnetic layer substantially not containing the SiO ₂ film near both ends on the track width side has a depth of 0.2 μm to 2 μm from both ends on the track width side, and the upper limit is from both ends on the track width side. It is desirable that the depth is 20% or less of the track width. The non-magnetic layer including the SiO ₂ film from the center of the track to the vicinity of both ends on the track width side is
Mainly two-layer structure of SiO ₂ film and the glass film, or mainly, a 3-layer structure of the SiO ₂ film and the glass film and the SiO ₂ film, a nonmagnetic layer containing substantially no SiO ₂ film, The mold glass and the SiO ₂ film of SiO ₂ and the glass film are in a mixed state.

[0005]

5 and 6 show the results of simulation of the stress distribution in the vicinity of the magnetic gap of the magnetic head core when the slider is fixed to the slit of the slider of the composite floating magnetic head by the mold glass. FIG. FIG. 5 relates to the magnetic head core of the present invention, and FIG. 6 relates to the conventional magnetic head core. In FIG. 5A, reference numeral 1 denotes a non-magnetic layer forming the magnetic gap and a glass film near the track width side end of the magnetic gap and SiO _2.
This is a region in which SiO ₂ and mold glass of the film are mixed and the SiO ₂ film is not substantially contained. Reference numeral ₂ is a region where the non-magnetic layer forming the magnetic gap has a three-layer structure of a SiO ₂ film, a glass film and a SiO ₂ film. In FIG. 5 (b), looking at the distribution of stress in the ferrite core piece, the metal magnetic thin film, and the non-magnetic layer, the stress applied to the ferrite core piece is small in both 1 and 2, and a small tensile stress acts on the metal magnetic thin film. is doing. Comparing the non-magnetic layers, the compressive stress acts in the region 1 which does not include the SiO ₂ film.
Even in the layered structure, a tensile stress acts on the glass film and a small tensile stress acts on the SiO ₂ film. The tensile stress acting on the glass portions 1 and 2 is not more than the fracture toughness value, and it is not the level of crack generation. The tensile stress acting on the SiO ₂ film is also the fracture toughness value of the SiO ₂ film. It's too late. As described above, in the floating magnetic head of the present invention, 0.2 μm to 2 μm from both ends of the magnetic head core after being incorporated in the slider on the track width side of the magnetic gap.
The range of m, substantially no SiO ₂ film, SiO ₂
By using a non-magnetic layer in which SiO _{2 of} the film, bonding glass, and mold glass are mixed, tensile stress caused by the difference in thermal expansion coefficient between the SiO ₂ film and the glass film when the molten mold glass is solidified Is alleviated and the occurrence of cracks can be suppressed. On the other hand, in the conventional magnetic head as shown in FIG. 6, the stress state applied to the ferrite core piece and the metal magnetic thin film as shown in (b) is the same as that of the magnetic head of the present invention, and there is no risk of cracking. . However, although the tensile stress acting on the glass film in the region 2 separated from the end on the track width side is less than the fracture toughness value, the tensile stress exceeding the fracture toughness value acts on the glass film in the region 1 near the end. This is the starting point of crack generation, and this crack progresses and expands. The reason for defining the depth from the track width side of the non-magnetic layer that does not substantially include the SiO ₂ film in the magnetic gap within the range of 0.2 μm to 2 μm from both ends is as follows. When the thickness is 0.2 μm or less, the effect of stress relaxation is small and it is impossible to prevent the occurrence of cracks. When the thickness is 2 μm or more, the portion of the SiO ₂ film formed for the purpose of accurately forming the magnetic gap length becomes small,
This is because the number of non-magnetic layers that do not substantially include the SiO ₂ film increases, and on the contrary, an accurate magnetic gap length cannot be formed. Further, the depth of 0.2 to 2 μm is not uniquely determined, but needs to be determined in relation to the track width. Especially, when the track width becomes narrow, it is better to set it to 20% or less of the track width. It is effective. In addition, Japanese Utility Model Laid-Open No. 57-189131 and Japanese Utility Model Laid-Open No. 57-1
Japanese Unexamined Patent Publication No. 89130 discloses a VTR head having a structure in which a predetermined step is provided in a recess near a gap where a sputtering layer is formed, and a glass material is allowed to penetrate into the recess near the gap. There is. However, the disclosed VTR head differs from the present invention in purpose, configuration, and action and effect.

[0006]

EXAMPLES The present invention will be described in more detail below with reference to examples. (Example 1) Fe-Al- having a diameter of 76 mm and a thickness of 2 mm
Using a Si alloy target, the flatness and the concave cross-sectional shape of the Mn—Zn single crystal ferrite substrates both face the magnetic gaps with a magnetron sputtering method to a thickness of 2 μm.
m Fe—Al—Si based metal magnetic thin film was formed. Sputtering was performed under the following conditions. RF power - 350 W motor - between target-substrate distance 70mm substrate temperature 300 ° C. The ultimate vacuum 5 × 10- ⁴ Pa gas pressure 7 × 10- ¹ Pa Next, SiO on the metal magnetic thin film of Fe-Al-Si system ₂
A film was formed, substrates were welded together with a glass film, and bonding glass was used to reinforce the adhesion. The welded body was cut and subjected to lapping and track notch processing to obtain a magnetic head core. As shown in FIG. 7, the magnetic head core 73 has an air bearing 76 for the non-magnetic slider 72.
It is buried in the slit 74 formed on the mold glass 4
After fixing with 5, finish processing such as the recording medium facing surface,
A composite type flying magnetic head with the same basic structure was manufactured. FIG. 2 shows the configuration near the magnetic gap of the magnetic head core. The magnetic gap depth is 5 μm, the SiO ₂ film is 0.2 μm, the glass film is 0.2 μm, and the gap length is 0.6 μm.
Three types of μm were used. , Bonding glass is PbO-
SiO ₂ —B ₂ O ₃ —Na ₂ O system, molded glass is PbO
Using _{-SiO 2 -Al 2 O 3 -B 2} O 3 O system. In order to study the relationship between the depth of the non-magnetic layer not including the SiO ₂ film, the crack generation state, and the magnetic gap length, the bonding temperature was 600 ° C ± 10 ° C, and the molding temperature was 500 ° C ± 50 ° C. The conditions were changed within the range.
The composition of Mn-Zn single crystal ferrite is MnO: 2.
7 mol%, ZnO: 18 mol%, the balance substantially Fe ₂ O ₃
I used the one.

(Embodiment 1) Table 1 shows the results of the crack generation situation. As shown in Table 1, it was found that no crack was generated in the magnetic gap when the depth of the non-magnetic layer containing no SiO ₂ film was 0.2 μm or more.

(Embodiment 2) The accuracy of the magnetic gap length of the magnetic head core in which cracks did not occur in Embodiment 1 was observed. The results are shown in Table 2. From Table 2, the depth of the non-magnetic layer not including the SiO ₂ film is 2μ.
If it is m or less, a gap accuracy of a level that practically does not hinder can be obtained.

[0009]

The levitation type magnetic head of the present invention reduces the occurrence of cracks in the non-magnetic layer by relaxing the stress concentration near both ends of the non-magnetic layer forming the magnetic gap on the track width side. The head characteristics can be improved.

[0010]

[Brief description of drawings]

FIG. 1 is a perspective view showing an electromagnetic conversion unit of a composite-type floating magnetic head of the present invention.

FIG. 2 is an enlarged view of a portion A in FIG. 1 of a magnetic gap portion of a composite type magnetic head core having both metal magnetic thin films according to the present invention.

FIG. 3 is an enlarged view of a magnetic gap portion of a composite magnetic head core of a shaped film formed by depositing a metal magnetic thin film of the present invention.

FIG. 4 is a perspective view showing a state in which a magnetic head core is embedded in a slit of a slider and fixed with a mold glass.

FIG. 5 is a diagram showing a result of simulation of stress distribution in a magnetic gap portion of the magnetic head core of the present invention.

FIG. 6 is a diagram showing a result of simulation of stress distribution in a magnetic gap portion of a conventional magnetic head core.

FIG. 7 is a perspective view of a composite type flying type composite magnetic head having a basic configuration.

FIG. 8 is a perspective view of a composite type magnetic head core having a basic configuration.

FIG. 9 is an enlarged view of a magnetic gap portion of a conventional magnetic head core.

[Explanation of symbols]

11 Composite-type floating magnetic head 12 Slider 13 Composite-type magnetic head core 14 Slit 15 Mold glass 16 Air bearing 21 Mn-Zn single crystal core piece 22 Glass film 23 SiO ₂ film 24 Nonmagnetic layer 25 not containing SiO ₂ film Metal magnetic thin film 31 Mn-Zn single crystal core piece 32 Glass film 33 SiO ₂ film 34 Non-magnetic layer 35 not containing SiO ₂ film Metal magnetic thin film Gl Gap length Tw Track width L Non-magnetic layer track not containing SiO ₂ film Depth from the width end

Claims (5)

[Claims] 1. A pair of Mn-constituting a magnetic head core.
Zn single crystal ferrite core pieces are arranged to face each other, a metal magnetic thin film is formed on at least one of the facing surfaces of the core pieces, and a composite magnetic head core having a magnetic gap is provided on an air bearing of a non-magnetic slider. In a composite type floating magnetic head embedded and fixed in a slit, the non-magnetic layer forming the magnetic gap is composed of a SiO ₂ film and a glass film from the center of the track to the vicinity of both ends on the track width side. A composite-type floating magnetic head having a composite structure comprising a non-magnetic layer and a non-magnetic layer substantially not containing a SiO ₂ film near both ends on the track width side. 2. The magnetic head core comprises a pair of Mn—Z.
2. The composite type flying magnetic head according to claim 1, wherein the n type single crystal ferrite core piece is a composite type magnetic head core in which a metal magnetic thin film is formed on both facing surfaces of the n type single crystal ferrite core piece. 3. The non-magnetic layer substantially not containing the SiO ₂ film near both ends on the track width side has a depth from both ends on the track width side of 0.2 μm to 2 μm. Item 7. The composite type flying magnetic head according to Item 1 or 2. 4. The nonmagnetic layer substantially not containing the SiO ₂ film near both ends on the track width side has a depth from both ends on the track width side of 20% or less of the track width. The composite type flying magnetic head according to claim 3. 5. The non-magnetic layer composed of a SiO ₂ film and a glass film from the center of the track to the vicinity of both ends on the track width side is mainly composed of a two-layer structure of a SiO ₂ film and a glass film, or mainly, SiO ₂ film, glass film and SiO
5. The composite type flying magnetic head according to claim 1, which has a three-layer structure of _two films.