JPS59135618A - Magnetic head - Google Patents

Abstract

PURPOSE:To improve the wear resistance and to reduce the output reduction in a high frequency region by laminating plural thin films of an amorphous magnetic alloy with a nonmagnetic intermediate layer having a specified coefft. of linear expansion in-between. CONSTITUTION:Plural thin films of an amophous magnetic alloy are laminated with a nonmagnetic intermediate layer in-between. The coefft. of linear expansion of the material forming the intermediate layer is 30-130X10<-1>deg<-7> at 25 deg.C. The coefft. of linear expansion is that measured when the material is in an ordinary bulk state. In case where the coefft. of linear expansion is not within said range, the adhesive strength of the intermediate layer to the magnetic layers is reduced, so the layers are stripped after long-term use, and the tracking accuracy is reduced.

Description

BACKGROUND OF THE INVENTION Technical Field The present invention relates to a magnetic head. More specifically, the present invention relates to a magnetic head having an amorphous magnetic alloy thin film.

Prior art and its problems Thin sheets of amorphous magnetic alloys have attracted attention as magnetic head materials because they exhibit high saturation magnetization and high magnetic permeability.

In order to form a narrow magnetic head with +11 tracks from an amorphous magnetic alloy thin plate, such as a rotary head for video recording, recording/playback or audio, or a magnetic head for a computer, CO-based amorphous magnetic material is used. A thin alloy plate is used as it is, or multiple sheets thereof are laminated to create a track width of several tens of micrometers or less, especially about 20 to 30 gm, and half-core cores in a predetermined shape are made by butting them together through a gap. are doing.

However, the video heads produced in this way are extremely thin, so they have the disadvantage of not being strong enough, deforming when mechanically rejected, and having poor accuracy after machining. There is.

Furthermore, since the thin plate of amorphous magnetic alloy has high elasticity, it deforms as it slides at high speed with the video magnetic recording medium, causing the head arm to become unbalanced and resulting in poor rotational running performance.

In order to eliminate such inconveniences, it is conceivable to form a thin film of an amorphous magnetic alloy by sputtering on a predetermined substrate to form a half-core core, and then form a magnetic head from this. In the magnetic head formed in this way, the disadvantages mentioned above are eliminated.

However, the magnetic head formed in this manner has a drawback of lacking in ml thickness resistance.

Further, there is a drawback that the eddy current phase cannot be ignored and the output decreases significantly in the high frequency range.

In such cases, such inconveniences can be alleviated by dividing the magnetic thin film and interposing a nonmagnetic thin film intermediate layer between the plurality of divided magnetic thin films.

However, with a normal intermediate layer, such as 5i02, when the medium is moved for a long period of time, separation occurs between the intermediate layer and the magnetic thin film, resulting in a decrease in tracking accuracy and various other problems.

II. OBJECTS OF THE INVENTION The present invention was developed in view of the above-mentioned circumstances, and its main objectives are (1) to improve wear resistance, to reduce output drop in the high frequency range, and to improve interaction with media. The object of the present invention is to provide a magnetic head with good tracking accuracy over a long period of time.

Such objects are achieved by the invention described below.

That is, the present invention has a laminate formed by laminating a plurality of amorphous magnetic alloy thin films with a non-magnetic intermediate layer interposed therebetween as a base body, and the material forming the intermediate layer has a coefficient of linear expansion of 30 to 130. X I O-0-
7de'.

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

The thin film in the present invention has magnetic properties and is in an amorphous state with substantially no long-range regularity.

Although there is no particular restriction on the composition of the amorphous magnetic alloy thin film, it is particularly preferable that it be represented by the following formula.

In the two-part formula 4, T represents CO or a combination of CO and one or more other transition metal elements.

That is, T may consist of Co alone, or may consist of CO and another transition metal element.

When T consists of Co and other transition metal elements, the other transition metal elements include Fe and Ni.

Cr, Mo, W, V, Nb,
T a , T i , Z rHf, Mn, Pt, R
u, Rh, Pd, Os.

Specific examples include Ir and the like, but the total amount thereof is preferably 38 at% or less.

Among such additive elements in T, one preferable example is Ru. Ru has a great effect in improving high-speed wear resistance and preventing a decrease in output when using metal tape (coated tape using alloy magnetic powder).

Note that Ru can be replaced with other platinum group elements, such as Pt, Rh
etc., such an effect will not be achieved.

In this case, the amount of Ru added is 8 at% or less, especially 0.5 to
It is preferably 6 at%, more preferably 1 to 5 at%.

Another preferred element is Cr.

By adding Cr, high-speed wear resistance and storage stability under high temperature and high humidity conditions are significantly improved.

In this case, the Cr addition content is 8 at% or less, especially 0.5 to 0.
It is preferably 6 at%, more preferably 0.5 to 5 at%.

Kono et al., other than Cr+7) VTR group, VB group, TVB group elements, Mo, W, V, Nb, T
a, Ti.

It is also preferable to add Zr and Hf. These additions improve high-speed wear resistance under high temperature and high humidity conditions.

In this case, the amount of these additions is 5 at% or less, especially 0.
It is preferably 1 to 2 at%.

Further, when R11, more preferably Ru+Cr, and still more preferably Ru+Cr+ (other rVB to {circumflex over (IV) group elements)] is included, even more favorable results can be obtained.

Furthermore, other additive elements may include Fe. Addition of Fe reduces magnetostriction.

In this case, the amount of Fe added is 6 at% or less, especially 0.1 to 6 at%.
It is preferable that it is at%, more preferably 2 to 5 at%.

Furthermore, Ni may be included.

Although Ni replaces Co and reduces material cost, it is understood that the amount added should be 10 at% or less.

In addition, Mn is also a suitable additive element.

On the other hand, X is a vitrification element.

Vitrification elements include B, Si, I', and C.

There are A1, etc., and any of these inserts may be used, but it is particularly preferable to use B or Si and B as essential components.

In this case, B is 10 to 35 at%, and if necessary, Si is 6
When the content is at % or less, the wear resistance is improved and favorable results are obtained.

Si/(Si+B) (7) atomic ratio is o or 0
．． When it is 2 or less, especially 0.05 to 0.15, even more favorable results can be obtained.

In addition, when P, C, A1, etc. are further contained, it is preferable that these are 0.5 at% or less.

Such a thin film usually has a thickness of 0.1 to 100
gm, preferably 0.1 to 30 pLm+7) thickness.

In such a magnetic thin film, a plurality of layers are laminated with a nonmagnetic intermediate layer interposed therebetween.

In the present invention, the material forming the intermediate layer must have a linear expansion coefficient of 3O-130X10-'deg-7 (25°C). In this case, the coefficient of linear expansion is
This is when it is in the normal bulk state.

If the coefficient of linear expansion exceeds l30 x 10-7deg-1 or becomes less than 30 x 10'7deg-', the adhesive strength between the intermediate layer and the magnetic layer decreases, resulting in delamination between the layers after long-term use. This results in a decrease in tracking accuracy.

Further, it is preferable that the material forming the intermediate layer has a Vickers hardness Hv of 2000 Kg/mm' or less in a normal bulk state.

This is because if Hv is less than 2,000, the flatness of the thin film end face after grinding at the core abutting surface becomes poor, the effective gap widens, and the output decreases particularly in the high frequency region becomes large.

In this case, Hv is 400-1500Kg/m m
' is even more preferable. This is because the wear resistance is improved and the drop in output in the high frequency range is reduced.

Materials exhibiting such physical properties include various inorganic substances, and particularly preferred ones include aluminum oxide, titanium oxide, magnesium liquefaction, composite materials thereof, and various types of glass.

Such an intermediate layer preferably has a thickness of 30 to 100 OA. As a result, the eddy current product decreases, and the drop in output in the high frequency range becomes extremely small.

1. The magnetic thin film and intermediate layer as described in 1-1- are stacked on each other to form a laminate.

In this case, the magnetic thin film generally has about 1 to 3 layers.

The total thickness of the laminate is 0.1 to 1100 p-,
(If preferred, it is about 0.1 to 30 gm.

The substrate used is usually non-magnetic.

In this case, there is no particular limit on the material of the body.

Therefore, any of various oxides, carbides, silicides, nitrides, glasses, etc. can be suitably used.

The substrate material may be appropriately selected and used in consideration of the physical properties of the amorphous magnetic alloy thin film, magnetic properties, sliding properties with the medium, etc.

There are no particular restrictions on the thickness of such a substrate, but
Usually, it is about 0.1 to 5 mm.

To form a laminate of an amorphous magnetic alloy thin film and a nonmagnetic intermediate layer on such a substrate -1-, a vapor phase deposition method, usually sputtering, is used.

2 As the sputtering method used, any known sputtering method can be used in which a target is sputtered by bombarded ions, and the target material is usually evaporated with a kinetic energy of several eV to about 100 eV.

Therefore, even if a plasma method is used in which the target is sputtered with ions such as Ar caused by abnormal glow discharge in an inert gas atmosphere such as Ar,
An ion beam method in which ion beams such as , Xe, etc. are irradiated may be used.

When using a plasma method, it may be so-called RF sputtering or so-called DC sputtering,
The device configuration may be either 2-pole, 4-pole, etc.
Furthermore, so-called magnetron sputtering may be used. In some cases, so-called reactive sputtering may also be used. Furthermore, various methods can be used as the ion beam method.

[Tagera to be used] - In normal cases, one with a corresponding composition may be used.

Note that there are no particular restrictions on the operating pressure, plate voltage, plate current, gap between electrodes, etc., and these can be set to arbitrary values depending on the conditions.

In such a case, an underlayer may be formed on one surface of the substrate, and a laminate of an amorphous magnetic alloy thin film and a nonmagnetic intermediate layer may be formed on this underlayer -1-.

Furthermore, a protective layer may be formed on -L of the laminate of the amorphous magnetic alloy thin film and the nonmagnetic intermediate layer.

In this way, the base body 2.2' on which the laminate 3.3' of the amorphous magnetic alloy thin film and the non-magnetic intermediate layer is formed has a predetermined shape as shown in FIGS. Processed into
Engineering, C-shaped core halves l, 1' and broken, front gear.
The pump section 4 and the rear gap section are brought together via a gap material 40 such as 5i02 to form a magnetic head. In this case, it is preferable that at least the abutting surfaces of the front gap portion be inclined from the normal line of the thin film forming surface to form a so-called azimuth angle.

Note that the core half 1.1' is a laminate of a thin film and an intermediate layer 3.
Furthermore, a protective body 5 made of the same material as the base body 2.2' can be adhered onto the base body 2.2'.

In such a case, after forming the thin film, it is preferable to perform heat treatment in a non-magnetic field or in a static magnetic field or a rotating magnetic field, if necessary.

Next, it is ground into a predetermined shape, and if necessary, it is ground to a predetermined thickness, and if necessary, it is further polished to make the core semi-dry.

Then, winding 8 is applied, winding is performed as shown below, and other necessary processing is performed, and the magnetic head is fixed to a support 9 to produce a magnetic head.

Note that the heat treatment described in -1- may be performed after shape processing and before winding.

(2) Specific effects of the invention Such a magnetic head is extremely useful for video recording, recording/playback, rotating heads for audio equipment, magnetic heads for computers, and the like.

The magnetic head of the present invention has extremely high wear resistance.

Furthermore, as a result of the eddy current product becoming extremely small, the output drop in the high frequency range becomes extremely small.

Furthermore, even if it is slid over a long period of time with a medium, there is very little separation between layers, and there are very few problems such as a decrease in tracking accuracy.

Further, the decrease in the surface roughness of the abutting surfaces is extremely small, and the effective gap does not widen to cause a decrease in output in the high frequency range.

(2) Specific Examples of the Invention Hereinafter, specific examples of the present invention will be shown and the present invention will be explained in more detail.

Example 2 A thin film of each non-quality magnetic alloy having the composition shown in Table 1 below was formed to a thickness of 30 pm 6 on an alumina substrate having a thickness of 30 pm.

Separately, the total thickness of the magnetic layer was maintained at 30 pLm, and an intermediate layer made of Al2O3 (67X10-7deg-') with a thickness of 200A was interposed in each 1X3 portion thereof.

In addition, the intermediate layer is made of KF2 glass (86 x 100-7
de-'), BK 7 glass (77 x 10''7d
eg -1), T i 02 (90X 10-0
-7de') was produced.

Furthermore, for comparison, the intermediate layer was made of SiO2 (4X 10
-7deg-') was produced.

Each of these thin films was formed by sputtering.

In this case, a target with a corresponding composition is used, and the operating argon pressure is 5.5×10 = Torr.
RF magnetron sputtering was performed at a plate voltage of 2 KV and input power of 4 W/crn'.

Next, this is ground and polished to form core halves l, 1' as shown in FIGS. 1 and 2.
They were brought together via a front gap material 5i02 of 31 Lm, and a predetermined winding 8 was applied to produce a magnetic head. Note that the azimuth angle was 6°.

Next, each magnetic head was mounted on an 8 mm video deck, and the following measurements 1) to 3) were performed.

1)) Rack accuracy 25°C, 150%RH, metal tape 3,7
Track accuracy was measured after running for 500 hours at 5 ml sec. In this case, O indicates ±Igm or less, and × indicates ±5pm or less.

2) Amount of Wear The metal tape was run for a period of time at 25° C. and 150% RH, and the amount of wear (in m) after running was measured using a surface roughness meter.

3) Storage property After storage at 70°C and 95% RH for 40 hours,
The f-characteristic deterioration (dB) at 0.5 MHz and 15 MHz before and after storage was measured.

These results are shown in Table 1.

From the results shown in Table 1, the effects of the present invention are clear.

[Brief explanation of the drawing]

1 and 2 show one example of the structure of the magnetic head of the present invention.
1 is a perspective view, and FIG. 2 is an enlarged partial front view. ■, 1'...Core half-open 2.2'...Base 3.3'...Amorphous magnetic alloy thin film and non-crystalline Laminated body with magnetic intermediate layer Applicant Tokyo Denki Kagaku Kogyo Co., Ltd. Representative Patent attorney Yo Ishii - 1

Claims (1)

[Claims] 1. A laminate formed by laminating a plurality of amorphous magnetic alloy thin films with a non-magnetic intermediate layer interposed therebetween is provided on a substrate, and the linear expansion coefficient of the material forming the intermediate layer is 30. ~130 x 10-0-7
2. The material forming the intermediate layer has a Vickers hardness of 2000.
2. The magnetic head according to claim 1, wherein the magnetic head is below Kg/mrn'. 3. Vickers hardness is 400-1500Kg/m
The magnetic head according to claim 2, which is m'. 4. The magnetic head according to claims 1 to 3, wherein the intermediate layer has a thickness of 30 to 100 OA. 5. The thickness of the laminate is 0. ．． The magnetic head according to any one of claims 1 to 4, wherein the magnetic head has a particle size of 1 to 1100 pL. 6. A magnetic head according to any one of claims 1 to 5, wherein the amorphous magnetic alloy has a composition represented by the following formula. Formula (In the above formula, T represents Co or a combination of Co and one or more other transition metal elements, and X represents a vitrification element. x + y = 100 at% , Among these, y is 5 to 35 at%.)