JPS6117210A - Magnetic head - Google Patents

Abstract

PURPOSE:To provide a magnetic head which has good resolving power, permits high-density recording and obviates the deterioration in electromagnetic conversion characteristics, particularly the resolving power, overwrite characteristic and erasing characteristic even after long-period use or preservation by specifying a material for a gap material. CONSTITUTION:The magnetic head has the gap consisting of the thin film consisting of at least >=1 kinds among Al2O3, ZrO2, MgO and Ba2TiO4 and a glass film. Since the gap having high magnetic resistance is thereby formed, the magnetic head has the good overwrite characteristic and high resolving power. The thin oxide film has the good adhesiveness to the core body and the thin glass film and is thermally and mechanically stable. The secure narrow gap is thus formed. The deterioration in the overwrite characteristic and resolving power which arises during use or upon lapse of time is consequently decreased considerably. The gap is highly resistant to a high temp. and high humidity and maintains the magnetic characteristics with least deterioration after the long- term preservation or use at and under the high temp. and high humidity. The running durability is good as well.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a magnetic head, and particularly to a narrow-gap magnetic head that uses an amorphous magnetic alloy and is used for digital recording on floppy disks and the like.

■ Prior Art In recent years, as the performance of information equipment has improved and the use of OA has progressed, there has been a desire for higher performance and smaller size of floppy disks, which are one of the recording media.

In response to such demands, 5- and 25-inch floppy disks, which are smaller than the 8-inch floppy disk, have been developed.

Recently, a 3.5-inch microfloppy disk (MFD), which is even smaller and has the same storage capacity as an 8-inch floppy disk, has been developed for practical use.

In order to realize such a compact floppy disk with a large storage capacity, it is necessary to realize high-density recording. In order to realize high-density recording, new characteristics are required for the recording medium and the magnetic head.

In order to improve the performance of recording media, it is necessary to develop magnetic materials with high coercive force.

Magnetic heads are also required to have improved characteristics. Conventionally, permalloy was used as the core material for magnetic heads for floppy disks in the early stages of practical use of floppy disks.

However, permalloy has various problems.

For example, the frequency band used by the floppy head (125K
Hz to 250 KHz) and the frequency band used by an audio head (20 KHz or less), the frequency band used by a floppy head is a high frequency band.

However, since permalloy has a small resistivity of 50 to 150 Ωcm, its effective magnetic permeability in a high frequency band rapidly decreases, resulting in poor magnetic properties such as reproduction output, S/N ratio, and resolution.

On the other hand, ferrite, which is also diverse, has a resistivity of IXI.
(The magnetic gap is as large as 1 Ωcm, and since the glass welding method is used for the magnetic gap, a strong narrow magnetic gap can be manufactured.

Therefore, recently, ferrite has been mainly used as the core material of magnetic heads for floppies. High-density recording can be achieved up to a certain level by using ferrite for the core material of the magnetic head.

By the way, in order to achieve even higher density recording, the coercive force (Hc) of the floppy disk, which is a magnetic recording medium, was set at Hc=2700e in the early days (γ-Fe as the magnetic material).
2O3) to H
c=6300e.

Furthermore, in a recording medium with a high coercive force made of alloy powder as a magnetic material, Hc=13000e.

Therefore, in order to record on such a high coercive force recording medium, it has become necessary to develop a core material for a magnetic head that has a high saturation magnetic flux density and whose effective magnetic permeability does not decrease in a high frequency band.

For this reason, sendust and amorphous alloys are attracting attention as core materials for magnetic heads.

Since these materials have a higher saturation magnetic flux density than ferrite, it is also possible to record on a high coercive force recording medium.

However, the problem with magnetic heads is not only the magnetic properties of the core material, but also the establishment of a gap manufacturing method for magnetic heads having a strong narrow gap from the viewpoint of reliability.

As for sendust, joining by silver solder welding is being considered.

However, in the case of an amorphous alloy, the crystallization temperature is low, so it cannot be processed at a temperature higher than a certain temperature.

Although there are proposals for a method of manufacturing a magnetic gap of 2.3 as in Japanese Patent Application Laid-Open No. 55-110241, no satisfactory solution has yet been found.

When realizing a magnetic head with a narrow gap and high magnetic flux density, not only the performance at the time of manufacture but also the deterioration over time become a problem.

In other words, the electromagnetic conversion characteristics deteriorate over time or due to repeated running due to relative temperature characteristics, adhesion or fixation, residual stress, specific resistance, etc. between the amorphous magnetic alloy core material and the gap material. .

For example, there have been major problems with resolution, override characteristics, erasure characteristics, etc., which are particularly related to gap length stability.

(2) Specific Purpose of the Invention The present invention has been made to solve the above-mentioned problems.

In other words, a magnetic head using an amorphous alloy has a strong magnetic gap with a narrow gap length, has good resolution, is capable of high-density recording, and has excellent electromagnetic conversion characteristics even when used or stored for a long time. In particular, it is an object of the present invention to provide a magnetic head that does not deteriorate in resolution, override characteristics, erase characteristics, etc.

Such objects are achieved by the invention described below.

That is, the present invention provides a magnetic head in which core halves made of an amorphous magnetic alloy are brought together and integrated with each other via a gap material, in which the gap material is an oxidized material adhered to at least the gap surfaces of both core halves. A magnetic head comprising a thin film made of at least l and w of aluminum, zirconium oxide, magnesium oxide, and barium titanate, and a glass film interposed between the thin films.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

The core in the magnetic head of the present invention is usually formed from a thin plate of an amorphous magnetic alloy.

When an amorphous magnetic alloy is used as a core material, it has good properties as a core, and even after extremely long-term use, there is little uneven wear on the media sliding surface of the head, and there is little variation in frequency characteristics or output level. Good 4 Obtain good results.

When an amorphous magnetic alloy thin plate is used as the core material, its composition may be of various compositions known for use in the core of a magnetic head', but in particular it has a high saturation magnetic flux density Bs, A composition represented by the following formula CI) is preferable because it is suitable for a high coercive force magnetic recording medium.

Formula CI) 'r,ry In the above formula, f is Fe and Col or Fe
and represents a combination of Co and l or more types of other transition metal elements.

In this case, other additive elements added in combination with Fe and Co as necessary include transition metal elements other than Fe and Co (Sc-Zn; Y-Cd; La-Hg; Ac
For example, Ni, Ti, Zr, , Hf, ■
, Nb, Ta, Cr, Mo, W, Mn, Ru, Rh, P
Specific examples include one or more of (7) such as d, O5, Ir, and Pt.

On the other hand, X is B, Si and B, or B or Si
and represents a combination of B and one or more other vitrifying elements.

In this case, examples of other vitrifying elements that may be added as necessary in combination with B or SL and B include P.
, C, Ge, Sn, A5L, and the like.

On the other hand, in the above formula CI) #, x+y=100at%
and y is 20 to 27 at%. That is, Fe
and the transition metal elemental content X with Co as an essential component is 7
The vitrification element component amount y containing B or Si and B as essential components is 3 to 80 at%, and is 20 to 27 at%. When y is less than 20 at%, it becomes difficult to make it amorphous, and when it exceeds 27 at%, the residual magnetic flux density Bs decreases.

Furthermore, essential components Fe and Co in the transition metal element components
The content of Fe is 1.5 to 5.6 at%, and Co is 45 to 7B, 5 at%.

Fe content is less than 1.5 at% (Co content is 78.5 at%
at%) 1. Or if it exceeds 5.6 at%,
Magnetostriction becomes large and magnetic permeability decreases.

When Co is less than 45 at%, Bs decreases.

In this case, in the above formula CI), T may consist of only Fe and Co within the above content range;
o and one or more of the other additive elements listed above.

When T consists only of Fe and Co, the Fe content is 1.
5 to 5.6 at%, more preferably 2 to 5.5 at%,
Co content is 67.4-78.5 at%, more preferably 67.5A-78 at%. T is Fe and C
When one or more other elements are included in addition to o, one or more of the other transition metal elements can usually be contained up to 25 at% in total.

If the content exceeds this range, problems such as decreased Bs and poor surface properties will occur.

One example of such an element is Ni.

Addition of Ni has the effect of replacing Co and reducing material costs, but as the amount of Ni increases, Bs decreases, so the Ni content is preferably 8 at % or less.

On the other hand, as one or more of the other elements, iron group (Fe, Co
, Ni), but the total amount of at least one transition metal element other than the iron group is preferably 12 at % or less. At this time, the decrease in Bs is small,
Excellent effects unique to each additive element are achieved.

As such an element, one or more of Ru, Cr, and Ti is particularly preferable.

In particular, when 0.5 to 8 at% of Ru is added, wear resistance is improved, and surface properties, punching workability, etc. are improved.

Moreover, when 1 to 8 at% Cr is added, corrosion resistance is improved.

When Ru of 0.5 to 8 at% and Cr of 1 to 8 at%, especially 2 to 6 at% are added in combination, these effects are further improved and more favorable results are obtained.

In addition, 0.05-'2at% Ti was replaced with these,
More preferably, when added in addition to these, more favorable results can be obtained;
, W, Mo, etc., may also be included.

In addition, when containing transition metal elements other than Fe and Co in this way, the total of these becomes 20 at% or less, and the Co content is 47.4 to 78.5 at%, more preferably 47.5 to 78 at%. %, ゛Also, the Fe content is 1.5
The content is preferably 5.6 at%, more preferably 2 to 5.5 at%.

On the other hand, the vitrification element component or B or Si and B are essential components.

In the case of Kono, when the B content is 3.3 to 27 at% and the Si content is 0 to 18.2 at%, Bs increases, the surface properties of the thin plate improve, and favorable results are obtained.

When the B content is 14.1 to 26.9 at% and the s' content is 0.1 to 5.4 at%, Bs becomes even higher, the surface properties are further improved, and Ru, Cr, etc. The effect of addition of the additional element becomes significant, and more favorable results are obtained.

Note that the vitrification element component Therefore, the content is preferably 0.5 at % or less. 6 The thin plate having the composition detailed above is an amorphous material having substantially no long-range regularity.

Further, the plate thickness is approximately 10 to 200 ILm. Such an amorphous magnetic alloy thin plate is manufactured according to a known high-speed quenching method.

That is, an alloy of a corresponding composition is ultra-quenched from the gas phase or liquid phase. In this case, usually.

An amorphous magnetic alloy is obtained by converting the alloy into a melt and ultra-quenching it from the liquid phase at a cooling rate of 104° C. 7 sec or more, usually at a cooling rate of 104 to 106° C./SeC, and solidifying it.

In order to super-quench a molten alloy, the molten alloy may be injected from a nozzle and quenched by various known methods such as a twin roll method, a single roll method, and a centrifugal quenching method, particularly the single roll method.

Such amorphous magnetic alloy thin plates are preferably laminated via an insulating adhesive layer to form core halves of a desired shape, and these are butted together as described below to form a magnetic head.
In particular, it is used as a magnetic head for floppy disks, video images, etc.

Alternatively, the thin plates are not laminated, but the thin plates themselves are used as core halves of a desired shape, and the core halves are butted together to form a magnetic head, particularly for flow 2P, video, etc. magnetic heads.

Such a core half for a magnetic head is usually made into a magnetic head in the following manner.

First, preferably, a predetermined heat treatment is performed on a thin plate obtained by an ultra-quenching method.

This heat treatment may be, for example, annealing in a non-magnetic field at a temperature below the crystallization temperature and above the Curie point, especially for the purpose of eliminating internal strain, or annealing at a temperature below the crystallization temperature and the Curie point or above. It may also be annealing treatment in a magnetic field for the purpose of removing strain and improving magnetic properties.

As for this latter annealing treatment in a magnetic field, either a static magnetic field, a rotating magnetic field, etc. may be used. These annealing heat treatments and their conditions are determined depending on the composition of the amorphous magnetic alloy and the desired magnetic properties. You may select one from among them as appropriate.

Next, such an amorphous magnetic alloy thin plate is usually punched into a predetermined shape using a die, and a plurality of the sheets are generally laminated with an insulating adhesive so as to have a predetermined track width to form a core half. Create.

Note that the core half 11 may have various known shapes such as an engineered shape as shown in FIGS. 1 and 2, a C-shape, etc.

These core halves are then brought together via a gap material as described below.

That is, as shown as an example in FIGS. 1 and 2, at least the gap end face on the core half body 11 has A1203.
, Z r02 , MgO.

A thin film 12 made of at least one type of Ba2TiO4 is provided as a base layer.

The thin film 12 as the base layer can be formed by sputtering or the like using a corresponding oxide.

Such thin films include AlI303 and ZrO2.

Mg, O, Ba2Ti04 may be used alone.

Alternatively, two or more of these may be used.

When there are two to four kinds of oxides, it is preferable that the amount of the added oxide is 20 wt% or less, more preferably 10 wt% of the main oxide.

In this case, AIL203, Z r02, MgO
.

Ba2TiO4 also includes those whose stoichiometric composition is slightly deviated.

Such underlayer components can interdiffuse with the oxide film on the surface of the amorphous magnetic alloy or the upper glass thin film to obtain high adhesion strength.

In addition, when two or more types of oxides are included, the additive amount is 20wt.
% or more, interdiffusion with the amorphous magnetic alloy and glass thin film is inhibited, and lattice distortion is likely to occur during thin film formation, making the thin film prone to cracking.
% or less.

When adhering, it is best to raise the temperature of the adherend (magnetic helad core) in order to increase the adhesion strength between the thin film and the core half.The temperature must be below the crystallization temperature of the adherend. , preferably 250°C or lower.

If there is a difference in thermal expansion coefficient between the thin film and the amorphous magnetic alloy material that forms the magnetic head, stress will remain in the thin film, causing cracks in the thin film or even further delamination of the thin film from the core half. It ends up.

However, a thin film made of at least one of the above oxides has a coefficient of thermal expansion of 120 x IO-? ('Cj)-
1, there is no such inconvenience.

The thickness of such a base layer thin film is 0.05 to 2.0.
OILm, particularly preferably 00O1 to 1.61Lm.

This is because if the film thickness exceeds 2.0 pm, the effect of the intermediate layer for obtaining sufficient adhesive strength is lost.

Further, if the film thickness is less than 0.05 pm, sufficient adhesion strength cannot be obtained.

A glass thin film 13 is laminated on such a thin film 12.

In the present invention, the glass thin film 13 is, for example, a low melting point glass,
For example, PbO-B2 o3 glass is used.

In this case, Pb080~90wt%, B20320~1
Approximately 0 wt% is preferable.

If necessary, Bi2 can be used as an element to lower the melting point.
By adding O3, 205, etc., a low melting point glass having a desired melting point is obtained.

'Glass thin films are usually laminated by sputtering.

The glass thin film 13 adheres well to the base layer thin film and forms a sufficiently strong gap. Furthermore, the oxide thin film is not damaged when the layer is deposited on the thin film.

The softening temperature of the glass thin film is preferably 500 to 700°C.

Further, the thickness of the glass thin film is preferably about 0.05 to 0.7 of the desired magnetic gap length.

If the glass thin film layer is thin and the gap length is less than 0°05, strong adhesive strength cannot be obtained.

On the other hand, if it is larger than 0.7, the thin oxide film serving as the base layer will not be able to absorb the stress during the formation of the glass thin film layer, resulting in small racks.

In this case, the thickness of the glass thin film is preferably 0.1 to 0.6 of the gap length.

Note that the thickness of the glass thin film is preferably 0.1 to 1.0 gm.

In this way, the core halves 11, each having the thin film 12 and the glass thin film 13 formed on at least the front and rear gap abutting surfaces, are integrated by abutting the gap abutting surfaces.

At this time, as shown in FIG.
A glass material 14 is placed between them.

This is then heat treated to form a magnetic head.

In this case, the vitreous 14 has a front and rear gap 1
5.

The glass used here is a low melting point glass.

In this case, the softening temperature is preferably 300 to 500°C.

As for the composition, PbO-8203 glass is particularly suitable. And usually Pb080-90wt%, B2
O3 is 10 to 20 wt%, and B i is added as an additive.
20'3 or v203 is added to adjust the desired softening temperature.

After granular glass material 14 made of such low-melting point glass is disposed near the abutting portion of both gears 2 on which glass thin film 13 is laminated, the entire magnetic core is heat-treated at 300 to 500°C. As a result, the gap abutting surfaces on which the glass thin films 13 are laminated are fused to form a glass film.

In order to bond the glass thin film sufficiently mechanically without damaging the other core bodies or underlying layers.

It is necessary that the heat treatment temperature ranges from the softening temperature to the melting temperature of glass.

The gap formed as above is 4p as a whole.
It is preferably less than m, more preferably 0.5 to
It is 2.0 gm. At this time, the effects of the present invention are more clearly realized.

The total film thickness of Thin 1112 and Glass Thin M13 is:
Overall, it is necessary that the gap length be equal to or 1.2 times or less the desired gap length of the magnetic head.

The magnetic head manufactured in this way is extremely useful in applications for floppy disks.

In addition, FIG. 4 shows two cores formed by butting together the core halves shown in FIGS. 1 and 2 as shown in FIG. 3, and integrating them via a spacer 16. An example of a 3-gap type floppy head is shown.

■Specific effects of the invention Al2O3, Zr02, MgO of the present invention.

A thin film made of at least one type of Ba2TiO4,
A magnetic head having a gap formed from a glass film has the following effects.

In other words, a gap with high magnetoresistance is formed, so
Good override characteristics and high resolution.

Further, the oxide thin film has good adhesion to the core body and the glass thin film, is thermally and mechanically stable, and forms a strong narrow gap. Therefore, there is very little deterioration in override characteristics or resolution that occurs with use or over time.

In addition, the gap has good resistance to high temperatures, the magnetic properties do not easily deteriorate even after long-term storage or use under high temperature and high humidity, and the running durability is also good.

(2) Specific Examples of the Invention Examples are given below to further demonstrate the effects of the present invention.

Example 70 (5,5Fe-94,5GO) -24(IO3
t-90B) An amorphous magnetic alloy thin plate was obtained by a single roll method using an alloy consisting of -6Ru. The plate thickness was 507 zm.

This amorphous magnetic alloy thin plate was annealed to remove internal strain.

By sputtering on this amorphous magnetic alloy thin plate,
The oxides shown in Table 1 below were deposited to form a base layer.

Next, as a second layer, a layer manufactured by Corning Inc. (c-1416) was provided. This softening temperature is 580°C.

The shape of the above core half is as shown in Figures 1 and 2,
I put these together.

Then, bead-like glass [Corning glass (
8463)) was placed near the magnetic gap as shown in FIG. 3, and heat treated at a temperature of 4.degree. C. to form a three-gap magnetic head as shown in FIG. 4.

The gap length is 1.51 Lm.

Separately, for comparison, a magnetic head was fabricated using a 1.5 gm thick Ti foil as a gap material and fixing it with a thermosetting resin.

The following measurements were performed on each of these samples.

1) Write the inner circumference at 125KH2 (the output at this time is IF), write the outer circumference at 25'0KHz (the output at this time is 2F), measure the recording and playback output, and set it to 2F/
The IF is expressed as a percentage and is defined as the resolution.

This resolution is measured initially and after 200 passes.

2) Override (0mer write) characteristic 12
After writing at 5KHz (output = IF), 25
Write (overwrite) while erasing at 0 KHz (output=2F), and measure the output IF' of the IF after writing 2F.

1F'/2F is expressed as an override characteristic. The unit is dB. The erasure rate is measured at the initial stage and after 200 buses.

3) Storage property At 40° C. and 90% RH, measure the rate of change in the above override characteristics after 240 hours.

These results are shown in Table 1.

-ζ0 The results shown in Table 1 clearly demonstrate the effects of the present invention.

That is, it can be seen that the magnetic head made of the gap material having the composition and film thickness of the present invention exhibits excellent resolution and override characteristics even at the initial stage, after many runs, and even after storage under poor conditions.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing one example of the core half body of the present invention, and FIG. 2 is a perspective view showing another example of the core half body of the present invention. FIG. 3 is a front view of the core half shown in FIG. 1 and the core half shown in FIG. FIG. 11... Core body 22... First layer 24... Second layer 32... Glass thin film. 34...vitreous

Claims (10)

[Claims] (1) In a magnetic head in which core halves made of an amorphous magnetic alloy are butted together and integrated through a gap material, the gap material is aluminum oxide coated on at least the gap surfaces of both core halves; A magnetic head comprising a thin film made of at least one of zirconium oxide, magnesium oxide, and barium titanate, and a glass film interposed between the thin films. (2) The magnetic head according to claim 1, wherein the thin film has a thickness of 0.05 to 2 μm. (3) The glass film according to claim 1 or 2, wherein the glass film is formed by depositing a glass thin film on the thin film, and disposing a vitreous substance between the glass thin films, and then heat-treating the film. magnetic head. (4) The magnetic head according to any one of claims 1 to 3, wherein the glass thin film has a softening temperature of 500 to 700°C. (5) The magnetic head according to any one of claims 1 to 4, wherein the glassy material has a softening temperature of 300 to 500°C. (6) The magnetic head according to any one of claims 1 to 5, wherein the glass thin film has a thickness of 0.1 to 1 μm. (7) The magnetic head according to any one of claims 1 to 6, wherein the heat treatment temperature is from the softening temperature to the melting temperature of glass. (8) The magnetic head according to any one of claims 1 to 7, wherein the magnetic head has a gap length of 4 μm or less. (9) The layers are arranged so that the total thickness of the thin film and the glass thin film is equal to or 1.2 times or less than the desired gap length of the magnetic head. The magnetic head described in any of the above. (10) Any one of claims 1 to 9, wherein the amorphous magnetic alloy has a composition mainly composed of Fe, Co, B, or B and Si, and containing one or more of Ru, Cr, and Ti. A magnetic head described in .