JP2001023109A - Magnetic head - Google Patents

Abstract

(57) [Problem] To improve the workability of a non-magnetic substrate as a guard material of a magnetic core. SOLUTION: A non-magnetic substrate 4 as a guard material of a metal magnetic thin film 5 constituting a magnetic core 8 is made of TiO ₂ and CaO.
As a main component, the content of TiO ₂ is 55 mol% or more,
And made of a non-magnetic material having a content of 74 mol% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic head having a magnetic core formed of a metal magnetic thin film.

[0002]

2. Description of the Related Art A magnetic head is mounted on a magnetic recording / reproducing apparatus and records and / or reproduces information signals on a magnetic recording medium (hereinafter referred to as recording / reproducing).
As such a magnetic recording / reproducing device, for example, a video tape recorder (VTR: VideoTape Recorder) or a DAT
(Digital Audio Tape) Like a recorder, a high-speed rotating drum is equipped with a magnetic head, and a tape-shaped magnetic recording medium is slid on this drum to perform recording and reproduction by the so-called helical scan method. is there. Also, a hard disk drive (HDD: Hard Disk Drive) that performs recording / reproduction with a magnetic head on a disk-shaped magnetic recording medium such as a magnetic disk or a magneto-optical disk.
k Drive) and floppy disk drive (FDD: Floppy)
Disk Drive).

[0003] The magnetic head is generally constructed by winding a coil around a magnetic core formed of a magnetic material having high magnetic permeability. Such a magnetic head is called an electromagnetic induction type (inductive type) magnetic head because it performs recording and reproduction on a magnetic recording medium using electromagnetic induction between a magnetic core and a coil.

In a magnetic head, a magnetic core functions as a path for transmitting magnetic flux, such as from a coil to a magnetic recording medium during recording and from a magnetic recording medium to a coil during reproduction. In the magnetic core, a minute gap, that is, a magnetic gap is formed in a portion facing the magnetic recording medium. The magnetic head records a magnetic signal on the magnetic recording medium by applying a leakage magnetic field generated in the magnetic gap to the magnetic recording medium.
Further, at the time of reproduction, the magnetic head takes in the magnetic field of the magnetic signal recorded on the magnetic recording medium into the magnetic core through the magnetic gap, and detects the magnetic field with the coil.

In recent years, in the field of magnetic recording, the recording density of magnetic signals has been further increased in order to reduce the size and capacity of magnetic recording media and to improve the quality of recorded video signals, for example. There is a demand for accurate recording and reproduction of minute magnetic signals. Therefore, for example, a metal tape in which a ferromagnetic metal powder as a magnetic powder used for a magnetic layer for recording a magnetic signal is made into a paint and applied on a base film, or a vapor deposition tape in which a ferromagnetic metal material is directly vapor-deposited on the base film Magnetic recording media exhibiting high coercive force, such as, for example, have been widely used.

In order to enable recording and reproduction on a magnetic recording medium exhibiting a high coercive force, for example,
A MI having a magnetic layer formed of a metal magnetic material having high magnetic permeability and high saturation magnetic flux density, such as an Fe-based alloy, an Fe-Ni-based alloy, and an Fe-Co-based alloy.
A G-type magnetic head or a laminated magnetic head has been proposed.

In the MIG type magnetic head, magnetic core halves formed by forming a metal magnetic thin film on a magnetic gap forming surface made of a Mn-Zn ferrite single crystal material are joined to each other and joined together by glass welding or the like. Magnetic head.

In the laminated magnetic head, the magnetic core halves sandwiching the magnetic layer between a pair of non-magnetic substrates are abutted against each other with the end faces of the magnetic layer facing each other. Is a magnetic head in which a magnetic gap is formed.

[0009]

By the way, in order to cope with a higher recording density and a higher transfer rate in the future, the magnetic head exhibits good electromagnetic conversion characteristics in a high frequency band and, for example, a small drum. Are required to be compatible with a recording and reproducing method such as a so-called helical scan method.

However, the above-mentioned MIG type magnetic head has a large impedance and is not suitable for use in a high frequency band. In addition, although the laminated magnetic head has excellent recording / reproducing characteristics in a high frequency band, it is necessary to manufacture a coil by winding a wire around a magnetic core. It is difficult to achieve a sufficient miniaturization to provide.

In order to solve the problem of the conventional magnetic head, the magnetic path is reduced by forming the magnetic core with a metal magnetic film, and a thin film coil is formed on the magnetic gap forming surface by a thin film forming step. (Hereinafter referred to as a bulk thin film magnetic head) is proposed in Japanese Patent Application Laid-Open No. 63-231713.

In this bulk thin-film head, the life as a magnetic head is generally determined by the wear characteristics of a non-magnetic substrate as a guard material holding a magnetic core. Therefore, conventional bulk thin film type magnetic head, wear characteristics was formed a non-magnetic substrate by good CaO-TiO ₂ -NiO-based material.

However, as described above, CaO-TiO
_The non-magnetic substrate formed of a _2- NiO-based material is, for example, a Mn-type magnetic head used in a MIG type magnetic head.
There was a problem that the processing resistance at the time of grinding with a grindstone was higher than that of a Zn ferrite single crystal material. As a result, in the conventional bulk thin film magnetic head, it is necessary to set a low grinding speed in order to manufacture with good yield, and there is a limit in improving the productivity.

Therefore, the present invention provides a magnetic head in which a non-magnetic substrate as a guard material exhibits good workability and has a good balance of abrasion between the non-magnetic substrate and a magnetic layer constituting a magnetic core. The purpose is to:

[0015]

According to the present invention, there is provided a magnetic head having a metal magnetic thin film formed obliquely on a non-magnetic substrate, a concave portion having a thin-film coil formed therein, and a butt made of a non-magnetic material. A magnetic gap is formed by butting a pair of magnetic core halves having flat surfaces and abutting these magnetic core halves on opposite end surfaces of the metal magnetic thin film via a non-magnetic material. Magnetic head. The non-magnetic substrate contains TiO ₂ and CaO as main components and has a TiO ₂ content of 55 mol% or more, and
It is formed of a non-magnetic material of less than mol%.

The magnetic head according to the present invention configured as described above has a small processing resistance when a non-magnetic substrate is subjected to grinding with a grindstone. Therefore, good workability can be ensured. Further, the wear amount of the metal magnetic thin film constituting the magnetic core and the non-magnetic substrate as the guard material for holding the metal magnetic thin film is well balanced.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIGS. 1 and 2 show a configuration example of a magnetic head according to the present invention.
The magnetic head 1 shown in FIG. The magnetic head 1 has a magnetic core formed of a metal magnetic thin film in order to reduce a magnetic path, and a thin-film coil formed by a thin-film forming process on a magnetic gap forming surface. Head.

As shown in FIGS. 1 and 2, the magnetic head 1 comprises a pair of magnetic core halves 2, 3 joined by metal diffusion bonding or the like. A pair of magnetic core halves 2,
3 is a non-magnetic substrate 4 made of a non-magnetic material, a metal magnetic thin film 5 formed on an inclined surface 4a of the non-magnetic substrate 4,
The low-melting glass 6 is formed on the non-magnetic substrate 4 so as to cover the metal magnetic thin film 5.
At least one of the pair of magnetic core halves 2 and 3 has a thin-film coil 7 for excitation and / or detection of induced electromotive force.
Is formed.

In the magnetic head 1, in a state where the pair of magnetic core halves 2 and 3 are joined via the gap material G,
The metal magnetic thin film 5 forms a magnetic core 8 as shown in FIG. However, the thin film coil 7 is not shown in FIG. When performing recording and reproduction on the magnetic recording medium, the magnetic head 1 applies the magnetic recording medium to the medium sliding surface 9.
Above, it is slid in the direction shown by arrow A in FIG. And
When reproducing a magnetic signal recorded on a magnetic recording medium,
The magnetic signal recorded on the magnetic recording medium is detected by the thin-film coil 7 via the magnetic core 8 and converted into an electric signal. When a magnetic signal is recorded on a magnetic recording medium, a change in a magnetic field generated in the thin-film coil 7 due to the supply of a current corresponding to the magnetic signal to be recorded is recorded via the magnetic core 8. Record on the medium.

In the magnetic head 1, the medium sliding surface 9 is formed in an arc shape with respect to the sliding direction of the magnetic recording medium in order to regulate the contact state with the magnetic recording medium. Also,
In the magnetic head 1, a contact width regulating groove 10 is formed in order to regulate the contact area with the magnetic recording medium. The contact width regulating grooves 10 are formed on both side surfaces of the magnetic head 1 in parallel with the sliding direction of the magnetic recording medium indicated by the arrow A in FIG.

In the magnetic head 1, the metal magnetic thin film 5 is formed of a material exhibiting good soft magnetism such as Sendust (Fe-Al-Si alloy). Further, the metal magnetic thin film 5 is formed on an inclined surface 4 a formed obliquely at a predetermined angle on the non-magnetic substrate 4.
Therefore, when the pair of magnetic core halves 2 and 3 on which the metal magnetic thin film 5 is formed are joined via the gap material G, the magnetic core 8 slides on the magnetic recording medium as shown in FIG. It is arranged obliquely to the direction A.

The metal magnetic thin film 5 has a substantially U-shaped cross section. That is, the metal magnetic thin film 5 has a concave portion 5a at a substantially central portion of the end surface on the side where the magnetic core halves 2 and 3 are joined.

For this reason, the metal magnetic thin film 5 is divided by the joining surfaces 2 a and 3 a of the magnetic core halves 2 and 3 in the front-rear direction and is exposed from the low melting point glass 6. And has the following. Then, the front butting surface 11 of the one magnetic core half 2 and the front butting surface 11 of the other magnetic core half 3 are butted via the gap material G to form the front gap 13. The rear butting surface 12 of one magnetic core half 2 and the rear butting surface 12 of the other magnetic core half 3 abut against each other to form a back gap 14.

In the front gap 13, the depth from the medium sliding surface 9 to the front gap end 13a on the side of the back gap 14 is referred to as depth.

The metal magnetic thin film 5 has a bonding surface 2a,
3a, the thin film coil 7 having the rear abutting surface 12 substantially at the center.
Has a coil forming recess 15 formed therein. A coil connection terminal 16 is formed in the coil forming recess 15 near the rear butting surface 12. The thin-film coil 7 is formed in the coil-forming recess 15, and the end on the center side is connected to the coil connection terminal 16.

The heights of the coil connection terminals 16 are adjusted so as to form the same surfaces as the joint surfaces 2a and 3a of the pair of magnetic core halves 2 and 3, respectively. In the magnetic head 1, when the pair of magnetic core halves 2 and 3 are joined, the pair of coil connection terminals 16 are also joined. Thus, in the magnetic head 1, when the pair of magnetic core halves 2 and 3 are joined, the pair of thin-film coils 7 are electrically connected.

The outer peripheral end of the thin film coil 7 is led out to the side opposite to the sliding surface of the magnetic recording medium. External connection terminals 17 are respectively formed on the pair of magnetic core halves 2 and 3 on the opposite side to the medium sliding surface 9. The outer peripheral end of the thin-film coil 7 is connected to the external connection terminal 17.

These external connection terminals 17 are exposed to the side surface of the magnetic head 1 so that they can be connected to the outside by the thin film coil 7.
And can be electrically connected. The pair of external connection terminals 17 are formed at positions where the heights of the pair of magnetic core halves 2 and 3 are different from each other so that a short circuit does not occur when the pair of magnetic core halves 2 and 3 are joined. Have been.

Incidentally, in the magnetic head 1, the nonmagnetic substrate 4 has a function as a so-called guard material for holding the metal magnetic thin film 5 constituting the magnetic core 8 with respect to the magnetic recording medium. Therefore, in the magnetic head 1, if the wear amount of the non-magnetic substrate 4 and the metal magnetic thin film 5 due to the sliding of the magnetic recording medium on the medium sliding surface 9 is different, a step occurs on the medium sliding surface. I will. In a conventional magnetic head,
Since the wear amount of the metal magnetic thin film 5 was larger than the wear amount of the non-magnetic substrate 4, the metal magnetic thin film 5 was recessed from the medium sliding surface 9, and there was a problem that so-called uneven wear occurred. In this case, in the conventional magnetic head, a gap is generated between the magnetic gap formed in the magnetic core 8 and the magnetic recording medium, which causes a spacing loss. As a result, there is a problem that the electromagnetic conversion characteristics particularly in a high frequency band are deteriorated.

However, in the magnetic head 1, the non-magnetic substrate 4 contains TiO ₂ and CaO as main components,
It is formed of a nonmagnetic material having an O ₂ content of 55 mol% or more and 74 mol% or less. Thus, in the magnetic head 1, the non-magnetic substrate 4 and the metal magnetic thin film 5
And the amount of wear on the magnetic recording medium can be made approximately the same, and the occurrence of uneven wear can be suppressed. Thereby, even if the magnetic head 1 is used for a long time,
It is possible to maintain good electromagnetic conversion characteristics in a high frequency band. Therefore, the magnetic head 1 can stably record and reproduce fine magnetic signals in response to the increase in recording density, and can be used as a long-life magnetic head.

The non-magnetic substrate 4 is formed of the above-mentioned material, and thus is made of, for example, a Mn-Zn ferrite single crystal material conventionally used in a so-called MIG type magnetic head or the like. Compared with the formed guard material, the processing resistance at the time of grinding with a grindstone can be made substantially the same. Therefore, in the magnetic head 1, when the non-magnetic substrate 4 is subjected to grinding,
The grinding speed can be set as high as the same as the case of the n-Zn ferrite single crystal material, which can contribute to improvement in productivity. Specifically, for example, it is possible to reduce the time required for the step of forming the contact width regulating groove 10 by performing the grinding process on the non-magnetic substrate 4.

In the magnetic head 1, the inclined surface 4a is formed at a predetermined angle on the non-magnetic substrate 4, but the inclined surface 4a is formed at an angle of about 45 °. Is desirable. Thereby, the track width accuracy of the magnetic head 1 is improved.

In the above description, the material for forming the metal magnetic thin film 5 is Sendust (Fe-Al-
(Si alloy), but the material is not limited to this. The metal magnetic thin film 5 is made of, for example, an Fe-Ta-N alloy, an Fe-Al alloy, an Fe-Si-Co alloy, an Fe-G
a-Si alloy, Fe-Ga-Si-Ru alloy, Fe-A
l-Ge alloy, Fe-Ga-Ge alloy, Fe-Si-G
It may be formed of a crystalline alloy such as an e-alloy, an Fe-Co-Si-Al alloy, or an Fe-Ni alloy.
The metal magnetic thin film 5 is made of one of Fe, Co, and Ni.
An alloy composed of the above elements and one or more elements of P, C, B, and Si, or an alloy containing Al, Ge, B
e, Sn, In, Mo, W, Ti, Mn, Cr, Zr,
Amorphous alloys such as metal-metalloid amorphous alloys typified by alloys containing Hf, Nb and the like, and metal-metal amorphous alloys mainly containing transition metals such as Co, Hf, Zr and rare earth elements May be formed. Further, the metal magnetic thin film 5 may be formed of a nitride-based soft magnetic alloy or a carbide-based soft magnetic alloy.

The metal magnetic thin film 5 may be formed of a single-layer metal magnetic thin film, but it is preferable that the nonmagnetic thin film layer and the magnetic thin film layer are alternately laminated. Thereby, the magnetic head 1 can reduce the eddy current loss, and can be a magnetic head having high sensitivity in a higher frequency band.

The magnetic head 1 configured as described above
When reproducing a magnetic signal recorded on the magnetic recording medium, a signal magnetic field from the magnetic recording medium is applied to the front gap 13.
Is applied around. When the direction of the applied signal magnetic field changes, the direction of the magnetic flux flowing through the magnetic core 8 changes. As a result, in the magnetic head 1, electromagnetic induction occurs, and a current corresponding to the magnetic signal recorded on the magnetic recording medium flows through the thin-film coil 7. And the magnetic head 1
By detecting the current flowing through the thin film coil 7,
A magnetic signal recorded on a magnetic recording medium is reproduced.

When recording a magnetic signal on a magnetic recording medium using the magnetic head 1, a current corresponding to the recording signal is supplied to the thin-film coil 7. Then, a magnetic flux is generated in the magnetic core 8 by the magnetic field generated from the thin film coil 7. Then, the magnetic head 1 records a magnetic signal on the magnetic recording medium by applying a leakage magnetic field in which the magnetic flux generated in the magnetic core 8 leaks at the front gap 13 to the magnetic recording medium.

Next, a method for manufacturing the above-described magnetic head 1 will be described in detail with reference to the drawings. When manufacturing the magnetic head 1, first, a plurality of magnetic core halves 2 and 3 are formed on the same substrate. Then, the magnetic head 1 is completed by bonding a pair of the substrates and separating the substrates into individual magnetic heads 1.

First, in order to manufacture the magnetic head 1, FIG.
As shown in (1), a substantially flat substrate 21 is prepared. The substrate 21 is to be the non-magnetic substrate 4 of the magnetic head 1 and, as described above, contains TiO ₂ and CaO as main components, the TiO ₂ content is 55 mol% or more, and 74 m
ol% or less of a non-magnetic material. The substrate 21 has, for example, a thickness of about 2 mm and a length and a width of about 30 mm.

As shown in FIG. 3, the substrate 21 has positioning notches 21b formed on both side surfaces 21a. The positioning notch 21b is used as a reference position for forming a winding groove 29, a medium sliding surface 9, and a contact width regulating groove 10 described later in a later step. Therefore, the positioning notches 21b need to be provided by the number of rows of the magnetic core halves 2 and 3 to be formed.

Next, as shown in FIG.
The first groove processing is performed on one main surface 21c. In the first groove processing, an angle of, for example, about 25 ° is formed with respect to one main surface 21c of the substrate 21 with a grindstone or the like.
A plurality of magnetic core forming grooves 24 are formed in parallel. Then, a plurality of inclined surfaces 21d are formed on the substrate 21 by the magnetic core forming grooves 24 formed by the first groove processing.

The inclined surface 21d formed here preferably has an inclination angle of about 25 ° to 60 ° with respect to the substrate plane.
Considering pseudo gap prevention and track width accuracy, 35
A tilt angle of about ゜ to 50 ° is more preferable. The magnetic core forming groove 24 formed by the first groove processing had a depth of 130 μm and a width of 150 μm.

Next, as shown in FIG. 5, a metal magnetic thin film 27 is formed on the entire surface of the substrate 21 on which the inclined surface 21d is formed. In this film forming step, the metal magnetic thin film 27
Is formed so that three metallic magnetic materials are laminated via a nonmagnetic layer. In this film forming step, for example, a sputtering method, a vapor deposition method, an MBE (Molecular Be
am Epitaxy) PVD (Physical Vapor Depos)
)) or the CVD (Chemical Vapor Deposition) method.

In this embodiment, the metal magnetic thin film 27 is formed by a sputtering method. At this time, in order to obtain good soft magnetic characteristics, the substrate 21 was inclined and sputtered, so that the sputtered particles were irradiated in a direction substantially perpendicular to the film formation surface. The tilt angle of the substrate 21 is arbitrary as long as desired soft magnetic characteristics can be obtained.

In this embodiment, the metal magnetic thin film 27 is
As described above, a non-magnetic thin film layer and a magnetic thin film layer were alternately laminated. Specifically, an Fe-based microcrystalline thin film having a saturation magnetic flux of 1.5 T was formed with a thickness of 4 μm as the magnetic thin film layer, and alumina was formed with a thickness of 0.15 μm as the nonmagnetic thin film layer. Then, the magnetic metal thin film 27 was formed by laminating these three magnetic thin film layers via a non-magnetic thin film layer. As described above, when a plurality of metal magnetic thin films 27 are stacked and formed, a material such as alumina, SiO ₂ and SiO can be used alone or in combination as the non-magnetic thin film layer. The thickness of the non-magnetic thin film layer is set to such an extent that insulation between adjacent metal magnetic layers can be obtained. If the thickness of the nonmagnetic thin film layer is too large, it acts as a pseudo gap.

Next, as shown in FIG.
A second groove is formed on the surface on which the groove 7 is formed in a direction substantially orthogonal to the magnetic core forming groove 24. In the second groove processing, a separation groove 28 formed to separate the magnetic core 8 into a predetermined size, and a winding for forming a magnetic gap in each magnetic core 8 separated by the separation groove 28. Wire groove 29
And are formed.

At this time, the winding groove 29 is formed by being positioned with reference to the positioning notch 21b of the substrate 21. Thereby, in a later step, as described later,
It becomes easy to process the depth of the front gap 13 in the magnetic head 1 with high accuracy.

At this time, portions other than the metal magnetic thin film 27 formed on the inclined surface 21d, that is, the metal magnetic thin film 27 formed at the bottom of the magnetic core forming groove 24 are removed by grinding.

Here, the separation groove 28 is a groove for forming each magnetic core 8 by magnetically separating the magnetic core 8 in the front-back direction on the substrate 21 and forming a closed magnetic path in each magnetic core 8. is there. Although two separation grooves 28 are formed in the example of FIG. 6, it is necessary to provide as many as the number of rows of the magnetic core halves 2 and 3 to be formed. In addition, the separation groove 28 must be formed so as to have a depth enough to completely cut the metal magnetic thin film 27 in order to magnetically separate the magnetic cores 8 arranged in the front-rear direction. is there. Specifically, the separation groove 28 has a depth of 150 μm from the bottom of the magnetic core forming groove 24, that is, 280 μm from the main surface 21 c of the substrate 21.
And the depth.

On the other hand, the winding groove 29 forms the concave portion 5a formed in the metal magnetic thin film 27 in the magnetic head 1 described above. Therefore, the winding groove 29 is formed by the magnetic core 8 having the front butting surface 11 and the rear butting surface 12.
In order to form the concave portion 15 for coil formation, it is necessary to form the metal magnetic thin film 27 at a depth that does not cut it. Therefore, the cross section of the metal magnetic thin film 27 is exposed on the surface of the winding groove 29.

The shape of the winding groove 29 is determined according to the lengths of the front butting surface 11 and the rear butting surface 12. Here, the width is set to about 140 μm, and And the length of the rear butting surface 12 was 85 μm. The winding groove 29 may have such a depth that the metal magnetic thin film 27 is not cut. However, if the winding groove 29 is too deep, there is a possibility that the magnetic path length becomes longer and the efficiency of magnetic flux transmission is reduced. The winding groove 29 is
Although the depth depends on the thickness of the thin film coil 7 formed in a step described later, it is set to 20 μm here.

Further, the shape of the winding groove 29 is not limited, but here, the front butting surface 1 serving as the front gap top 13 a in the magnetic head 1.
The side surface on one side is an inclined surface 29a of about 45 °. Thereby, the magnetic core 8 has a structure in which the magnetic flux is concentrated on the medium sliding surface 9 side, thereby improving the sensitivity. When the inclined surface 29a is formed, it may be formed, for example, in a circular or polygonal shape.

Next, as shown in FIG. 7, a low-melting glass melted on one main surface 21c of the substrate 21 on which the magnetic core forming groove 24, the separation groove 28 and the winding groove 29 are formed as described above. 30 is filled. At this time, the low melting glass 30
Is desirably performed at a heat treatment temperature sufficient for the metal magnetic thin film 27 to obtain good soft magnetic characteristics. Thereby, the heat treatment of the metal magnetic thin film 27 and the filling of the low-melting glass 30 can be performed in the same step. In the step of filling the low melting point glass 30, it is necessary to completely fill the groove formed in the substrate 21. Therefore, the low-melting glass 30 has a viscosity at the above-mentioned heat treatment temperature of 10 ² Pa · s to 10 ⁶ Pa · s, more preferably 1 Pa · s to 10 ⁶ Pa · s.
Desirably, the pressure is about 0 ³ Pa · s to 10 ⁵ Pa · s.

In the present embodiment, the metal magnetic thin film 2
7 shows a coercive force of 30 A / m or less by heat treatment at 520 ° C., and good soft magnetic properties can be obtained. Therefore, SiO ₂ , PbO, B ₂ O ₃ , and Bi ₂ O ₃ are used for the low melting point glass 30. Glass having a viscosity at 520 ° C. of about 10 ^4.5 Pa · s as a main component was used.

After that, the low-melting glass 30 is cooled and solidified, and the surface of the solidified low-melting glass 30 is flattened.

In this flattening process, it is desirable that the substrate 21 is polished and flattened to such an extent that a part of the substrate 21 is slightly exposed. When a part of the substrate 21 is not exposed as described above, the pair of magnetic core halves 2 and 3 in the magnetic head 1 are used.
When these are joined, there is a possibility that the opening angle of the track edge becomes small and fringing becomes large. However, if the exposure width is too large, the low melting point glass 30 and the substrate 2
When the etching rate is different from 1, a step occurs in a step of forming the thin-film coil 7 described later.
Therefore, it is desirable that the exposed width at this time is smaller than the width at the innermost periphery of the thin film coil 7.

Next, as shown in FIG. 8, a terminal groove 31 is formed by subjecting the solidified low-melting glass 30 to grinding using a grindstone or the like. The terminal groove 31 is formed so as to be located immediately above the above-described separation groove 28, and has a width and a depth of 100 μm. Then, a good conductor such as Cu is filled in the terminal groove 31 by a plating method or the like.
After that, a flattening process is performed. The good conductor such as Cu filled in the terminal groove 31 becomes the external connection terminal 17 in the magnetic head 1 described above.

Next, as shown in FIG.
The coil forming recesses 15 are formed by performing an etching process on 0, and a thin film coil 7 is formed in the coil forming recesses 15 in a thin film.

The concave portion 15 for forming a coil is formed in a substantially rectangular shape having the rear abutting surface 12 substantially at the center thereof.
It is formed by performing an etching process on portions other than the terminal 2 and the coil connection terminal 16. The coil forming recess 15 has a groove 15a reaching the terminal groove 31 from one end thereof.

Thereafter, a thin film coil 7 is formed in the coil forming recess 15. The thin-film coil 7 has one end 7a disposed on the coil connection terminal 16 and the rear abutting surface 1.
It has a shape wound many times so as to draw a circle centered at 2. The thin-film coil 7 is drawn out into a groove 15 a formed at one end of the coil forming recess 15, and the other end 7 b is electrically connected to an external connection terminal 17 made of a good conductor filled in a terminal groove 31. Connecting.

When the thin film coil 7 is formed, first, the above-described coil shape is patterned with a photoresist. Next, Cu is formed in the coil forming recess 15.
And the like are formed into a thin film by a technique such as plating so as to have a thickness of about 3 μm. Then, by removing the photoresist, the thin film coil 7 having a patterned coil shape can be formed. In forming the thin-film coil 7, not only the plating method described above but also a sputtering method or a vapor deposition method can be used.

In this embodiment, the thin film coil 7 is formed on each of the pair of magnetic core halves 2 and 3 in the magnetic head 1. However, the thin film coil 7 may be formed only on one side.

Next, a protective layer (not shown) for protecting the thin-film coil 7 from contact with the outside air is formed. This protective layer is formed so as to fill the coil forming recess 15 in which the above-mentioned thin film coil 7 is formed. The protective layer is preferably formed of a non-magnetic insulating material that is not removed by the oxygen ashing.

Specifically, as a non-magnetic insulating material, Al
Examples include oxides such as ₂ O ₃ , Ta ₂ O ₅ , SiO ₂ , ZrO ₂ , and TiO ₂ , and inorganic substances such as glass. Here, as the protective film, Al ₂ O ₃ was sputtered to a thickness of 0.4 μm.
m was formed over the entire surface of the substrate 21. At this time, the protective film also covers the front butting surface 11 and the rear butting surface 12 which are exposed on one main surface of the substrate 21, but the portions covering these are removed in a step described later. Note that this protective film can be formed only in a predetermined region by using a so-called mask sputtering method or a lift-off method. Examples of the method for forming the protective film include, besides the sputtering method, an evaporation method and spin coating of coating type SiO ₂ .

Next, as shown in FIG. 10, the substrate 21 in which the magnetic core halves 2 and 3 are formed in a plurality of rows in parallel is formed of one magnetic core half 2 and the other magnetic core half 3 in one row. Then, the magnetic core half block 33 is formed.

The magnetic core half block 33 is mirror-finished by polishing one main surface 33a. At this time, the front butting surface 11 and the rear butting surface 12 covered with the protective film are exposed to the outside.

Next, as shown in FIG. 11, the pair of magnetic core half blocks 33 is accurately positioned to perform metal diffusion bonding. At this time, the pair of magnetic core half blocks 33
The patterning of Au is performed on the bonding portion, and the upper ends of the front butting surfaces 11 are opposed to each other by aligning the end surfaces of the notches 21b for positioning, thereby accurately positioning.
Then, a pair of butted magnetic core half blocks 3
By applying a predetermined temperature and pressure to 3,
The magnetic head block 38 is manufactured by performing metal diffusion bonding.

As described above, the front butting surfaces 11 of the pair of magnetic core half-blocks 33 are rear butted by accurately aligning the end surfaces of the positioning notches 21b so that the upper ends of the front butting surfaces 10 face each other. The surfaces 12 and the coil connection terminals 15 can be accurately opposed to each other.

In this embodiment, the metal diffusion bonding is performed by patterning Au.
The pair of magnetic core half blocks 33 may be joined using an adhesive, water glass, or the like.

Next, as shown in FIG. 12, the magnetic head block 38 is separated into the individual magnetic heads 1. At this time, the magnetic head block 38 is, for example, B- in FIG.
Cut at the portion indicated by line B. At this time, the angle of the inclined surface 21d formed on the substrate 21 and the magnetic head block 38
The angle between the magnetic recording medium and the magnetic gap in the magnetic head 1, that is, the azimuth angle is determined according to the angle formed by the angle at which the laser beam is cut.

In the present embodiment, the metal magnetic film 27
The magnetic head block 38 is cut so that is substantially parallel to the sliding direction of the magnetic recording medium, so that the azimuth angle of the magnetic head 1 is substantially the same as the angle of the inclined surface 21 d of the substrate 21.

At this time, first, the magnetic head block 38
Is cut in the longitudinal direction in order to expose the surface serving as the medium sliding surface 9 with reference to the positioning notch 21b. Then, the magnetic head block 38 is subjected to cylindrical cutting on the exposed surface so as to have a cylindrical shape, and this surface becomes the medium sliding surface 9. afterwards,
The magnetic head block 38 has a positioning notch 21b.
The contact width regulating groove 10 is ground with reference to. The contact width regulating grooves 10 are formed at portions corresponding to both side surfaces of the medium sliding surface 9 of each magnetic head 1 separated from the magnetic head block 38.

In the magnetic head block 38, since the medium sliding surface 9 is processed with the positioning notch 21b as a reference as described above, it is cut to a predetermined position with high precision. For this reason, the depth which is the depth from the facing surface 9 to the front gap top 13a in the magnetic head 1 can be reduced. Therefore, in the magnetic head 1, the density of the magnetic flux generated in the front gap 13 is increased, and the core efficiency is improved.

In the magnetic head block 38,
Since the contact width regulating groove 10 is processed based on the positioning notch 21b, it is ground with high precision to a predetermined depth. For this reason, in the magnetic head 1, the shape of the magnetic core 8 cut out by the contact width regulating groove 10 can be determined with high accuracy, and the core efficiency of the magnetic core 8 does not decrease.

As described above, the magnetic head 1 is completed.

Next, the magnetic head 1 described above will be described.
The case where a sample substrate corresponding to the non-magnetic substrate 4 is actually manufactured based on the above and an evaluation test of wear characteristics and workability is performed will be described. First, as shown below,
_A plurality of sample substrates having different contents of ₂ were produced.

That is, commercially available TiO ₂ powder and CaCo ₃ powder were weighed so that the final composition ratio of TiO ₂ and CaO was determined, and pure water was added thereto and wet-mixed in a ball mill for 24 hours. . Next, the mixture was added to 100
After drying at 20 ° C. for 20 hours or more, pulverizing with an Ishikawa-type raikai machine, and calcining at 1100 ° C. for 5 hours. Next, the calcined sintered body was pulverized again by the Ishikawa-type raikai machine.

Next, pure water was again added to the pulverized powder, and wet mixing was performed in a ball mill for 24 hours. Next, this mixture was dried at 100 ° C. for 20 hours or more, pulverized with an Ishikawa-type raikai machine, and then granulated by adding a 10% by weight aqueous solution of polyvinyl alcohol (PVA) to 10% by weight of the total powder weight.

Next, a pressure of 80 MPa was applied to press-mold into a flat plate, and calcined in oxygen at a temperature of 1250 ° C. to 1400 ° C. Next, 100MPa by Ar gas
a) is subjected to HIP (Hot Isotropic Press) treatment in a temperature range of 1150 ° C. to 1350 ° C.
_A plurality of sample substrates containing ₂ and CaO as main components and different TiO ₂ contents were produced. Table 1 below shows the composition ratio of each sample substrate.

[0079]

[Table 1]

Table 1 also shows a comparison substrate used as a non-magnetic substrate in a conventional magnetic head. That is, the first comparative substrate is MnO
-Made of NiO-based material, the second comparative substrate is
CaO-TiO ₂ was formed by -NiO material, third
The comparative substrate was made of a Mn-Zn ferrite single crystal material.

Evaluation Test of Wear Characteristics In this evaluation test, a plurality of sample substrates manufactured as described above and first to third comparative substrates were used as the non-magnetic substrate 4 and the above-described magnetic heads were used. A magnetic head similar to No. 1 was produced. The shape of each magnetic head is 1.5 mm in width, 2 mm in height, 0.2 mm in thickness,
The contact width on the medium sliding surface 9 on which the magnetic recording medium slides is 8
The shape was set to be 0 μm. The track width is 12.
It was 3 μm.

Each of these magnetic heads is mounted on a digital video recorder (DCR-PC7) manufactured by Sony Corporation, and a digital video tape (DVM-DVM) manufactured by Sony Corporation is used.
60N2) was slid for 500 hours in an environment of 25 ° C. and 50% RH. At this time, the digital video tape is 2
Replaced every 4 hours. Then, the change in the amount of protrusion of the magnetic head from the drum was measured to determine the amount of wear. The smaller the amount of wear, the better the wear resistance. The initial setting of the amount of protrusion of the magnetic head from the drum is 30
μm.

Evaluation Test for Workability In this evaluation test, a plurality of sample substrates manufactured as described above and the first to third comparative substrates were tested using a slicing machine which is generally used. And 5 passes of the rotating whetstone. Then, the processing resistance applied to each sample substrate and the comparative substrate in the thickness direction at this time was measured and averaged for five passes. The dimensions of each sample substrate and the comparison substrate to be processed were 30 mm in length and width and 1 mm in thickness, respectively.

The processing conditions at this time were as follows: the rotating grindstone used was SD3 / 8 (R200), the rotational speed of the rotating grindstone was 5000 rpm, and the feed speed of the rotating grindstone was 30.
mm / min, and the cut depth was 0.1 mm.

The results of evaluation tests performed on each sample substrate and comparative substrate as described above are summarized in Table 2 below.

[0086]

[Table 2]

The “state of pores” in Table 2 is indicated by a circle when the porosity of each sample substrate is 0.1% or less, and is indicated by a cross when the porosity exceeds 0.1%. .
This indicates that the sample substrate indicated by “x” in “pore state” in Table 2 has many pores that are not densified even after the HIP treatment, and the non-magnetic substrate 4 of the magnetic head 1 This indicates that it is not suitable for use. That is, the first and second sample substrates having a TiO ₂ content of less than 50 mol%, and the eleventh to thirteenth sample substrates having a TiO ₂ content of more than 74 mol% have a high density even after the HIP treatment. There are many pores that are not converted, which damages the magnetic recording medium during recording and reproduction.
It is not suitable for use as a guard material for a magnetic head.

As is clear from the wear amount in Table 2, the third to fifth sample substrates having a TiO ₂ content of less than 55 mol% were CaO-TiO ₂
-Wear is three times or more as compared with the second comparative substrate formed of the NiO-based material. Therefore, the life of the magnetic head manufactured using these sample substrates as a guard material is extremely short. Therefore, the third to fifth sample substrates are not suitable for use as a guard material for a magnetic head.

As is clear from the working resistance in Table 2, the sixth to tenth sample substrates having a TiO ₂ content of 55 mol% or more and 74 mol% or less were the second comparative samples. It is about 1/2 as compared with the substrate, and shows almost the same processing resistance as the third comparative substrate formed of a Mn-Zn ferrite single crystal material having excellent workability.

From the above results, the non-magnetic substrate as a guard material of the magnetic layer constituting the magnetic core was made of TiO ₂ and Ca
By using a non-magnetic material containing O as a main component and having a TiO ₂ content of 55 mol% or more and 74 mol% or less, the balance between the wear amount of the metal magnetic thin film and the non-magnetic substrate is excellent, and uneven wear is reduced. It can be seen that a magnetic head which is reduced and has a long life and excellent workability can be realized.

Further, as is clear from the wear amount in Table 2, the content of TiO ₂ is 60 mol% or more,
The magnetic head manufactured using the seventh to tenth sample substrates having a content of 74 mol% or less is CaO-TiO _2.
-The wear amount is reduced as compared with the second comparative substrate formed of the NiO-based material. Therefore, by using a nonmagnetic substrate having such a composition as a guard material, it is possible to realize a magnetic head having a longer life than a conventional magnetic head.

[0092]

As described above, the magnetic head according to the present invention has a low processing resistance when a non-magnetic substrate is subjected to grinding with a grindstone. Therefore, good workability can be ensured. Further, the magnetic head according to the present invention is excellent in the balance of the wear amount between the metal magnetic thin film forming the magnetic core and the non-magnetic substrate as the guard material. For this reason, uneven wear of the metal magnetic thin film can be suppressed, the life is long, and the recording / reproducing operation can be stably performed even in a high frequency band. Thus, according to the present invention,
It is possible to accurately and stably record and reproduce fine magnetic signals corresponding to the increase in recording density, and to realize a magnetic head having a long life and high productivity.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a magnetic head shown as one configuration example of a magnetic head according to the present invention.

FIG. 2 is an enlarged perspective view of a main part showing a medium sliding surface of the magnetic head.

FIG. 3 is a diagram for explaining the method for manufacturing the magnetic head, and is a perspective view showing a substrate.

FIG. 4 is a view for explaining the same method, and is a perspective view showing a substrate on which first groove processing has been performed.

FIG. 5 is a view for explaining the same method, and is a perspective view showing a substrate on which a first metal magnetic thin film is formed.

FIG. 6 is a view for explaining the same method, and is a perspective view showing a substrate on which a second groove processing has been performed.

FIG. 7 is a view for explaining the same method, and is a perspective view showing the substrate in a state where each groove is filled with low-melting glass.

FIG. 8 is a view for explaining the same method, and is a perspective view showing a substrate in which terminal grooves are formed in low-melting glass.

FIG. 9 is a view for explaining the same method, and is a perspective view of an essential part showing a substrate on which a concave portion for forming a coil is formed.

FIG. 10 is a view for explaining the same method, and is a perspective view showing a magnetic core half block.

FIG. 11 is a diagram for explaining the same method, and is a perspective view showing a state where a pair of magnetic core half blocks are butted.

FIG. 12 is a diagram for explaining the same method, and is a perspective view showing a magnetic head block.

[Explanation of symbols]

1 magnetic head, 4 non-magnetic substrate, 4a inclined surface, 5
Metal magnetic thin film, 5a concave portion, 6 low melting point glass, 8 magnetic core, 10 width control groove, 11 front butting surface, 1
3 Front gap, 13a Front gap top, 14 Back gap, G gap material

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Seiichi Ogata 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5D033 AA02 BA07 BA22 BA35 BA61 BB01 DA31 5D093 AA01 AA03 AA04 AA05 AC01 AC04 AD05 EA02 FA27 HA01 JB03

Claims (2)

[Claims] 1. A pair of magnetic core halves having a metal magnetic thin film formed obliquely on a non-magnetic substrate, having a concave portion in which a thin-film coil is formed, and having a flat butted surface made of a non-magnetic material. A magnetic gap formed by abutting the magnetic core halves such that the end faces of the metal magnetic thin film face each other via a nonmagnetic material, wherein the nonmagnetic substrate is made of TiO. ₂ and CaO as main components,
The content of TiO ₂ is 55 mol% or more, and 74 mol
% Of a non-magnetic material. 2. The magnetic head according to claim 1, wherein the nonmagnetic substrate has a TiO ₂ content of 60 mol% or more and 74 mol% or less.