JP2000011314A - Magnetic head and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deterioration in the magnetic permeability of magnetic films at a high frequency and to improve the output characteristics of a magnetic head at the high frequency by specifying the film thickness of films for joining the magnetic head constituted by joining a pair of nonmagnetic substrates via magnetic films and the films for joining. SOLUTION: The magnetic permeability of the magnetic metallic films 13 exist as the major factor for governing the output characteristics of the magnetic head 10 at the high frequency. This magnetic permeability is deteriorated by the eddy current loss flowing to the magnetic metallic films 13 and the metallic films 14 for joining. The eddy current loss is larger as the film thickness of the magnetic metallic films 13 and the metallic films 14 for joining is larger and, therefore, the film thickness of the metallic films 14 for joining is regulated in order to suppress the deterioration in the magnetic permeability of the magnetic metallic films 13 by lessening the eddy current. If the film thickness of the metallic films 14 for joining is <=300 nm, the magnetic permeability is kept at η50% even if the frequency is 40 MHz and the output characteristics of the magnetic head 10 at the high frequency may be improved. The film thickness of the metallic films 14 for joining is preferably specified to <=300 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used for recording and reproducing an information signal as a magnetic signal on a recording track of a magnetic recording medium at a high density, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Magnetic recording / reproducing apparatuses using a magnetic recording tape or the like as a magnetic recording medium, such as a video tape recorder (VTR), a digital audio tape recorder (DAT), and a digital data recording apparatus, record on a magnetic recording medium. To read information signals such as read audio signals and video signals, or to write information signals to a magnetic recording medium, to read and reproduce information signals from a signal recording surface of the magnetic recording medium and to read signals from the magnetic recording medium. A magnetic head for writing and recording an information signal on a recording surface is provided.

In recent years, recording signals have been increased in density and frequency in order to increase the image quality of recording or reproduction of video signals, or to increase storage capacity and transfer at high speed. . In response to the increase in the density of the recording signal, F is used as a magnetic powder for the magnetic layer of the magnetic recording medium.
High coercive force magnetic recording media such as a metal tape in which a ferromagnetic metal powder such as e, Co, and Ni is applied on a base film, and a vapor-deposited tape in which the ferromagnetic metal material is directly vapor-deposited on the base film are used. I have. Since these high coercive force magnetic recording media have a high residual magnetic flux density Br and a high coercive force Hc, the head material of the magnetic head is also required to have a high saturation magnetic flux density Bs and a high magnetic permeability.

Further, in response to the increase in the frequency of the recording signal, there is a demand for a head structure utilizing a head material exhibiting high magnetic permeability at a high frequency, and a head material having less noise. In view of the above, for example, an iron-based alloy sandwiched between two substrates made of a non-magnetic material such as ceramics,
A so-called stacked magnetic head has been developed in which a metal magnetic film made of a ferromagnetic metal such as an iron-nickel alloy or an iron-cobalt alloy is used as a track portion.

[0005] This laminated magnetic head is manufactured by forming a metal magnetic film on one substrate by, for example, sputtering and integrating the two, and bonding the other substrate on the metal magnetic film. As the bonding method, a glass fusion method has been frequently used, but since a highly reliable glass has a high melting point, when a material weak to heat such as an amorphous magnetic film is used as a material for the metal magnetic film, There has been a problem that the original characteristics of the material cannot be sufficiently brought out. Therefore, a so-called low-temperature metal diffusion bonding method of bonding using a noble metal material such as a noble metal or an alloy thereof that is difficult to oxidize has been developed.

[0006]

In a laminated magnetic head using the low-temperature metal diffusion bonding method described above, a bonding metal film made of a noble metal material having a relatively low electric resistance adheres to a metal magnetic film or a nonmagnetic film. , The induced current easily flows through the metal magnetic film and the bonding metal film at a high frequency, and the eddy current loss due to the induced current deteriorates the magnetic permeability of the metal magnetic film. The deterioration of the magnetic permeability is more remarkable as the frequency is higher, and is a problem in increasing the frequency of a recording signal increasingly required in magnetic recording and reproduction.

The present invention has been made in view of the above circumstances, and has as its object to provide a magnetic head capable of reducing deterioration of the magnetic permeability of a magnetic film at high frequencies and a method of manufacturing the same.

[0008]

According to the present invention, there is provided a magnetic head having a structure in which a pair of non-magnetic substrates are joined via a magnetic film and a joining film. This is achieved by having a thickness of 300 nm or less. Further, according to the present invention, there is provided a method for manufacturing a magnetic head for joining a pair of non-magnetic substrates via a magnetic film and a joining film, wherein the joining film has a thickness of 300 nm.
This is achieved by including a step of forming a film with a thickness of m or less.

According to the above structure, the bonding film is formed thin to reduce the eddy current loss due to the induced current flowing through the magnetic film and the bonding film at a high frequency. Deterioration is suppressed, and output characteristics of the magnetic head at high frequencies can be improved.

[0010]

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Note that the embodiments described below are preferred specific examples of the present invention,
Although various technically preferable limits are given, the scope of the present invention is not limited to these modes unless otherwise specified in the following description.

As described in the prior art, the main factor governing the output characteristics of the magnetic head at high frequencies is the magnetic permeability of the metal magnetic film, and the magnetic permeability flows through the metal magnetic film and the bonding metal film. Deterioration is caused by eddy current loss due to induced current. Since the eddy current loss increases as the thickness of the metal magnetic film and the bonding metal film increases, the eddy current loss is reduced and the magnetic permeability of the metal magnetic film is suppressed from deteriorating. Regulates the thickness of the bonding metal film.

Therefore, a metal magnetic film having a magnetic permeability of about 3500 at 1 MHz is formed to a thickness of 4 μm, the magnetic permeability of the metal magnetic film is measured, and an Au bonding metal film is formed on the metal magnetic film by a thickness of 75 to 600 nm. And the permeability of the metal magnetic film was measured to determine the range of the thickness of the bonding metal film.
FIG. 1 is a diagram showing, for each frequency, a value obtained by dividing the magnetic permeability after forming the bonding metal film by the magnetic permeability before forming the bonding metal film.

As is apparent from FIG. 1, as the thickness of the bonding metal film increases, the magnetic permeability decreases as the frequency increases. For example, if the thickness of the bonding metal film is 60
In the case of 0 nm, when the frequency is 40 MHz, the magnetic permeability is 50%.
The film thickness of the bonding metal film is 30
In the case of 0 nm or less, the permeability is 5 even at a frequency of 40 MHz.
It stays below 0%. Therefore, by reducing the thickness of the bonding metal film, the output characteristics of the magnetic head at high frequencies can be improved.
It is desirable that the thickness be 0 nm or less.

FIG. 2 is a perspective view showing an embodiment of the magnetic head of the present invention. The magnetic head 10 has a configuration in which a pair of magnetic core halves 11, 12 constituting a closed circuit are abutted and joined and integrated. Each magnetic core half 1
Reference numerals 1 and 12 each have a configuration in which a metal magnetic film 13 is sandwiched between substrates 15 made of a nonmagnetic material via a bonding metal film 14. A magnetic gap g is formed at the butted end surface of the metal magnetic film 13 on the side of the magnetic recording medium sliding surface 10a in contact with the magnetic recording medium. Also, each magnetic core half 11,
A winding groove 16 for restricting the depth of the magnetic gap g and winding the wire is provided on the abutting surface 12.

Here, as the substrate 15, ceramics,
Non-magnetic ferrite, crystallized glass and the like can be cited, but CaO which is a material having high strength, which is a material in consideration of workability and abrasion resistance, a coefficient of thermal expansion with the metal magnetic film 13, and the like.
Ceramic materials such as —TiO ₂ —NiO materials are desirable. As the metal magnetic film 13, besides various ferromagnetic materials, for example, a ferromagnetic alloy material having a high saturation magnetic flux density and excellent soft magnetic properties is used. Any of conventionally known materials can be used irrespective of quality or amorphous.

As a ferromagnetic crystalline alloy, for example, Fe-
Al-Si alloy, Fe-Si-Co alloy, Fe-N
i-based alloy, Fe-Al-Ge-based alloy, Fe-Ga-Ge
Alloy, Fe-Si-Ge alloy, Fe-Si-Ga alloy, Fe-Si-Ga-Ru alloy, Fe-Co-S
i-Al-based alloys and the like are listed. Further, in order to further improve the corrosion resistance and wear resistance, Ti, Cr, Mn, Z
r, Nb, Mo, Ta, W, Ru, Os, Rh, Ir,
At least one of Re, Ni, Pd, Pt, Hf, and V may be added.

Examples of the ferromagnetic amorphous alloy include a so-called amorphous alloy, for example, an alloy comprising one or more elements of Fe, Ni, and Co and one or more elements of P, C, B, and Si; Or Al, Ge, Be,
Sn, In, Mo, W, Ti, Mn, Cr, Zr, H
Metal-metalloid amorphous alloys such as alloys containing f, Nb, and the like, and metal-metal amorphous alloys mainly containing transition elements such as Co, Hf, and Zr, and rare earth elements, and the like.

The metal magnetic film 13 may be formed by alternately stacking magnetic films via an insulating film in order to avoid eddy current loss in a high frequency band. As the insulator film, for example, an electrical insulating film such as an oxide or a nitride such as SiO ₂ , AlO ₃ , or SiN ₄ can be used. Examples of the bonding metal film 14 include Au, Ag, Pt, Pd, and alloys thereof. As a method of forming the metal magnetic film 13 and the bonding metal film 14, a vacuum thin film forming technique typified by a sputtering method, a vacuum deposition method, an ion plating method, an ion beam method, or the like using an apparatus having excellent film thickness controllability. Adopted. Further, a plating method may be used.

3 to 12 are process diagrams showing an embodiment of the method of manufacturing a magnetic head according to the present invention. First, CaO—TiO ₂ —Ni whose both surfaces are mirror-finished as shown in FIG.
On one surface of a rod-shaped core substrate 1 made of O, as shown in FIG.
And 100 nm of SiO ₂ alternately laminated) 13 to form a first strip-shaped core substrate 2 by sputtering, and further, on the metal magnetic film 13 and the metal magnetic film 13
As shown in FIG. 5, a bonding metal film 14 of Au is formed on the opposite substrate surface on which the
The second strip-shaped core substrate 3 is formed by sputtering, for example, to a thickness of 100 nm by a sputtering method.

Next, as shown in FIG. 6, a plurality of second strip-shaped core substrates 3 are bonded to the metal magnetic film 13 and the bonding metal film 14.
Are laminated together with the surface on which only the bonding metal film 14 is formed, and pressurized at, for example, 10 MPa to 50 MPa, and heated at 200 ° C. to 400 ° C. to form each of the strip-shaped cores. The substrate 2 is subjected to low-temperature metal diffusion bonding to form a laminated core substrate 4. Then, the laminated core substrate 4 is cut in directions AA ′, BB ′, and CC ′ orthogonal to the bonding surface, and FIG.
The magnetic core half blocks 5 and 6 are prepared as shown in FIG. Further, as shown in FIG. 8, a winding groove 1 extending on one surface of each magnetic core half block 5, 6 along its longitudinal direction.
6 is formed. Then, each magnetic core half block 5, 6
Is smooth-polished, and a non-magnetic material serving as a gap material, for example, a gap spacer made of Au / Cr is formed on the smooth-polished groove forming surface by a sputtering method.

Next, as shown in FIG. 9, the groove forming surfaces of the magnetic core half blocks 5 and 6 are abutted to each other and heat-treated, and are joined and integrated to form a rod-shaped magnetic core block 7. Then, as shown in FIG.
With the sliding surface, which is one surface of
Then, a rod-shaped glass 8 made of low melting point glass is inserted, and heat treatment is performed to fill the upper portion of the winding groove 16 with glass. Here, the glass plays a role of reinforcing the joining of the magnetic core half blocks 5 and 6 and preventing a decrease in strength when the magnetic head 10 is worn due to sliding with the magnetic recording medium.

Then, as shown in FIG. 11, a portion to be a sliding surface of the magnetic core block 8 is provided with a curvature and wrapped to a predetermined depth to slid the magnetic recording medium sliding surface 10a.
To form Finally, as shown in FIG. 12, directions FF ′, GG ′, HH ′, I−
The magnetic head 10 is cut at I ′ and JJ ′ as shown in FIG.

[0023]

As described above, according to the present invention,
The deterioration of the magnetic permeability of the magnetic film at high frequencies can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a change in magnetic permeability of a magnetic film and a frequency depending on the thickness of a bonding film of a magnetic head of the present invention.

FIG. 2 is a perspective view showing an embodiment of the magnetic head of the present invention.

FIG. 3 is a first process chart showing an embodiment of a method of manufacturing a magnetic head according to the present invention.

FIG. 4 is a second process chart showing an embodiment of the method of manufacturing a magnetic head according to the present invention.

FIG. 5 is a third process chart showing an embodiment of the method of manufacturing a magnetic head according to the present invention.

FIG. 6 is a fourth process chart showing an embodiment of the method of manufacturing a magnetic head according to the present invention.

FIG. 7 is a fifth process chart showing an embodiment of the method of manufacturing a magnetic head according to the present invention.

FIG. 8 is a sixth process chart showing an embodiment of the method of manufacturing a magnetic head according to the present invention.

FIG. 9 is a seventh process chart showing an embodiment of the method of manufacturing a magnetic head according to the present invention.

FIG. 10 is an eighth process diagram showing an embodiment of a method of manufacturing a magnetic head according to the present invention.

FIG. 11 is a ninth process diagram illustrating an embodiment of a method of manufacturing a magnetic head according to the present invention.

FIG. 12 is a tenth process chart showing an embodiment of a method of manufacturing a magnetic head according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Core board, 2, 3 ... Strip-shaped core board, 4
..Laminated core substrate, 5, 6 ... Magnetic core half block, 7 ... Magnetic core block, 8 ... Bar glass,
DESCRIPTION OF SYMBOLS 10 ... Magnetic head, 10a ... Sliding surface of a magnetic recording medium, 11, 12 ... Half magnetic core, 13 ... Metal magnetic film, 14 ... Metal film for joining, 15 ... Substrate, 16
... Winding grooves

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masaya Kosaka 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo F-term in Sony Corporation (reference) 5D093 AA02 AD05 BC07 BC18 FA16 HB25 JB10

Claims (5)

[Claims] 1. A magnetic head having a structure in which a pair of non-magnetic substrates are joined via a magnetic film and a joining film, wherein the thickness of the joining film is 300 nm or less. 2. The magnetic head according to claim 1, wherein the bonding film is made of a noble metal material. 3. A method for manufacturing a magnetic head in which a pair of non-magnetic substrates are bonded via a magnetic film and a bonding film, the method comprising a step of forming the bonding film to a thickness of 300 nm or less. Manufacturing method of a magnetic head. 4. The magnetic head according to claim 3, wherein the bonding film is made of a noble metal material. 5. The magnetic head according to claim 3, wherein the bonding method is a low-temperature diffusion bonding method.