JPS63124208A - Magnetic head - Google Patents

Abstract

PURPOSE:To prevent core bases from generation breakage or cracks by forming a non-magnetic soft metallic thin film between the core bases and magnetic thin films adhering to the magnetic gap forming face side, and even if thermal stress due to the difference of thermal expansion coefficients between the core bases and the magnetic thin films is applied, allowing the soft metallic layer to absorbed the thermal stress. CONSTITUTION:The magnetic thin films 12, 15, 27 adhering to projection parts 10, 13, 22, 25 formed on the core bases 11, 14, 23, 26 are stuck to the surface of the soft metallic layer 31. Soft and non-magnetic metal such as aluminum, gold and silver can be used for a material forming the soft metallic layer 31 and a vacuum film forming method such as vacuum evaporation method or sputtering method is especially proper to the formation. Even if thermal stress due to heat generated at the time of forming the magnetic thin films or the difference of thermal expansion coefficients between the core bases and the magnetic thin films is applied to the core bases, the thermal stress is absorbed by the soft metallic layer 31 and the core bases 11, 14, 23, 26 can be prevented from generating clips or cracks.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is applicable to video tapes, flexible disks, etc.
The present invention relates to a magnetic head suitable for application to a magnetic recording medium having high coercive force.

[Prior art]

In recent years, in order to meet the demand for higher density magnetic recording, there has been a trend toward increasing the coercive force of magnetic recording media. Along with this, there has been a demand for a magnetic head capable of recording on a magnetic recording medium having such a high coercive force. development is underway.

FIGS. 3 and 4 show an example of this type of magnetic head that has been proposed in the past (Japanese Patent Laid-Open No. 61-74113).

FIG. 3 is a plan view of a conventional magnetic head seen from the medium sliding surface side, and FIG. 4 is a sectional view taken along the line B-B in FIG. The head mainly consists of a recording/reproducing head 1, an erasing head 2, and a nonmagnetic material 3 for preventing magnetic influence between the two magnetic heads.

The recording/reproducing head 1 includes a first core half 4, a second core half 5 opposite thereto, an excitation coil 7 wound in a coil groove 6 provided in the first core half 4, and the first core half 4. It mainly consists of a reinforcing layer 8 made of a non-magnetic material such as glass filled on both sides of the joint between the core half 4 and the second core half 5.

The first core half 4 has a first core base 11 having a chevron-shaped protrusion 10 approximately in the center of the side surface facing the magnetic gap 9.
and a first magnetic thin film [12] deposited on the protrusion lO.

The first core base 11 is formed of a ferrite having high magnetic permeability, such as Mn-Zn ferrite or Ni-Zn ferrite.

On the other hand, the first magnetic thin film 12 is formed of a crystalline alloy or an amorphous alloy having high saturation magnetic flux density and high magnetic permeability. Examples of the crystalline alloy include iron-aluminum-silicon alloy, iron-silicon alloy, and iron-nickel alloy. In addition, as amorphous alloys, iron,
and one or more elements selected from the group of nickel and cobalt.

An alloy consisting of one or more elements selected from the group of phosphorus, carbon, boron, and silicon, or an alloy containing these as the main component, such as aluminum, germanium, beryllium, tin, molybdenum, and indium.

There are alloys to which elements such as tungsten, titanium, manganese, chromium, zirconium, hafnium, and niobium are added, and alloys containing cobalt and zirconium as main components and each of the above-mentioned additional elements. The first magnetic thin layer 12 made of these materials is formed to have a thickness of about 50 μm.

The second core half 5 is also similar to the first core half 4,
A second core base 14 made of ferrite with high magnetic permeability and having a chevron-shaped protrusion 13 formed approximately at the center of the side surface facing the magnetic gap 9; a high saturation magnetic flux density coated on the protrusion 13; The second magnetic thin conductor 15 is made of a metallic magnetic material having high magnetic permeability.

The magnetic gap 9 is formed of a non-magnetic film made of glass, for example, and has a thickness of about 100 to 140 μι (gap length). 2 core half 5. The second magnetic thin film [15 formed in the second magnetic thin film 15 is interposed in a portion facing the tip of the protruding portion 10.13.

The recording/reproducing head 1 is constructed by joining the first core half 4 and the second core half 5 through the magnetic gap 9, and then filling both sides of the protrusion 10.13 with reinforcing layers 8. Assemble it.

The erasing head 2 is basically the same as the recording/reproducing head 1, mainly.

A first core half 16 and a second core half 17 opposite thereto
, an excitation coil 19 wound around coil i#18 provided on the second core half 17, and a reinforcing layer 20 made of a non-magnetic material such as glass.

The first core half 16 is made of high magnetic permeability ferrite and has two chevron-shaped protrusions 22 formed at a predetermined interval (track width) on the side surface facing the magnetic gap 21.
A first core body 23 made of a metallic magnetic material having high saturation magnetic flux density and high magnetic permeability and deposited on the protrusion 22.
It is composed of magnetic film@24.

The second core half 17 is also similar to the first core half 16,
A second core base 26 made of ferrite with high magnetic permeability and having two chevron-shaped protrusions 25 formed at a predetermined interval on the side surface facing the magnetic gap 21; and the protrusions 25.
It is composed of a 2A thin layer 27 made of a metallic magnetic material having high saturation magnetic flux density and high magnetic permeability, which is deposited on top.

The magnetic gap 21 is made of, for example, glass.

The first magnetic thin film 24 formed on the first core half body 16 and the second core half body 1
The second magnetism formed in 7? The protruding portion 2 of JWJ27
2.25 is interposed in the portion facing the tip.

The erase head 2 is assembled by joining the first core half 16 and the second core half 17 through the magnetic gap 21, and then filling both sides of the protrusion 22.25 with reinforcing layers 20. It will be done.

As shown in FIG. 3, the magnetic gap 9 of the ia @ reproducing head 1 and the two magnetic gaps 21 of the erasing head 2 are arranged in the medium running direction of the magnetic gap 9 (direction of arrow A).
The magnetic gap 21 is located on both sides of the extension line. For this purpose, a recording track is formed on the magnetic recording medium by the recording/reproducing head 1, and immediately after the recording/reproducing head 1, both ends of the recording track are partially erased by the erasing head 2 to regulate the track width.

Incidentally, the angle θ of each of the protrusions 10.13 and 22.25 is
Considering the demand for narrower track widths and productivity issues, 1 usually 45＠~120°F! It is formed at the same time.

[Problem that the invention seeks to solve]

By the way, the conventional magnetic head configured as described above has magnetic thin films 12.15.24 on the protrusions 10, 13, 22.25 formed on the core base 11.14.23.26.
．． In the process of applying 27, as shown in Figure 3,
Chips and cracks at the tips of protrusions 10, 13° 22.25 2
There is a problem that 8 is likely to occur. Chips and cracks in the cough area 2
8 will not only result in poor yields and high product costs, but also cause serious problems such as damage to the magnetic recording medium if this defective magnetic head is installed in a recording/reproducing device. There is a possibility that

An object of the present invention is to suppress chipping and splitting of the tip of the protruding portion of the core half when manufacturing the core half.

[Means for solving problems]

As a result of research, the inventor of the present application found that the cause of the chipping and cracking that occurs in the core substrate is thermal stress caused by the heat during forming the magnetic GL film and the difference in the coefficient of thermal expansion between the core substrate and the magnetic thin film. I learned something.

The present invention was made based on this knowledge, and
A magnetic head is formed by joining two core halves through a magnetic gap. and a magnetic thin film deposited on the magnetic gap forming surface side of the core base, wherein a non-magnetic soft metal thin film is disposed between the core base and the magnetic thin film. It is characterized by the fact that it has been interposed.

[Effect]

When a soft metal layer is interposed between the core substrate and the magnetic thin film,
Even if thermal stress due to the difference in coefficient of thermal expansion acts between the core substrate and the magnetic thin film when forming the magnetic thin film, the thermal stress will be absorbed by the soft metal layer and the core substrate will not be chipped. No cracking occurs.

〔Example〕

FIG. 1 is a plan view showing an embodiment of the magnetic head according to the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. Components similar to those shown in FIG. 4 are designated by the same reference numerals.

This soft metal layer 31
．． It is applied on the protrusion to+t3+22.25 formed in 26. Further, the magnetic thin film 12)ts, 24,2
7 is deposited on this soft metal layer 31.

Metal materials forming the soft gold 721Ps31 include aluminum, gold, silver, etc., and have a tensile strength at break of 2000.
It is possible to use a soft non-magnetic metal with a weight of ~4500 kg/aJ or less, a laminate of two or more metals selected from these recommended groups, or a non-magnetic laminate of these metals and other substances. can.

As a means for forming this soft metal layer 31, vacuum evaporation method,
Although any known thin film forming means such as sputtering and cladding methods can be used, vacuum film forming methods such as vacuum evaporation and sputtering are particularly suitable because of their good productivity. Also.

The thickness of the soft gold i-layer 31 must be such that this portion does not become a pseudo gap and adversely affect the recording and reproducing characteristics.

From this point of view, the thickness of the soft metal layer 31 is 0.3 μm.
It is preferable to set the degree of PA to 3 μm.

Detailed explanations of other members similar to those shown in FIGS. 3 and 4 will be omitted to avoid duplication.

The magnetic head of the above embodiment has a core half of 11°14.23°.
．． Since the soft metal layer 31 is interposed between the magnetic thin film 26 and the magnetic thin film 12, 15, 24. Even if stress acts on the core substrate, the thermal stress is absorbed by the soft metal layer 31 and the core substrates 11, 14
．． No chips or cracks occur in 23126.

In the above embodiment, a composite magnetic head in which a recording/reproducing head and an erasing head are integrated was explained as an example, but the gist of the present invention is not limited to this, and a single recording/reproducing head may be used. Alternatively, it can be applied to an erasing head in exactly the same way.

Another aspect of the present invention is a magnetic head including a core base having high magnetic permeability and a core half having a magnetic Y4 film formed of a ferromagnetic metal material having high saturation magnetic flux density and high magnetic permeability. This is because a non-magnetic soft metal layer is interposed between the core substrate and the magnetic thin film, and the material, dimensions, shape and IL of each part are different. It goes without saying that flfZ is not limited to those shown in the above embodiments, and may be appropriately selected as necessary.

〔Effect of the invention〕

As explained above, in the magnetic head of the present invention, since the soft metal layer is interposed between the core substrate and the magnetic thin film, the thermal stress acting on the core substrate when forming the magnetic thin film is reduced, and the core No chips or cracks will occur on the base.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a magnetic head according to an embodiment of the present invention as seen from the medium sliding surface side, FIG. 2 is a sectional view taken along line AA in FIG.
FIG. 3 is a plan view of a conventionally known composite magnetic head as seen from the medium sliding surface side, and FIG. 4 is a sectional view taken along line BB in FIG. 1: recording/reproducing head, 2: erasing head, 3: non-magnetic material,
4: first core half, 5: second core half, 6: coil groove,
7: Excitation coil, 8: Reinforcement layer, 9: Projection, 10: First
core base, 11: first magnetic thin film, 12: protrusion, 13:
Second core base, 14: Second magnetic thin film, 15: Magnetic gap, 16: First core half, 17: Second core half, 18:
Coil groove, 19: Excitation coil, 20: Reinforcement layer, 21: Magnetic gap, 22: Projection, 23: First core base. 24: first magnetic thin film, 25: protrusion, 26: second core base, 27: second magnetic thin film, 31: soft metal layer. Figure 1 1: To recording/reproduction・Continuation 2::14 To・Sotoζ 3;
5.24.27: aa? 14P131: Soft metal layer

Claims (3)

[Claims] (1) A magnetic head consisting of two core halves joined through a magnetic gap, in which the core halves have a core base made of a magnetic material with high magnetic permeability and a core body made of a magnetic material with high saturation magnetic flux density and high Made of ferromagnetic metal material with magnetic permeability,
A magnetic head comprising a magnetic thin film deposited on the magnetic gap forming surface side of the core base, characterized in that a non-magnetic soft metal layer is interposed between the core base and the magnetic thin film. . (2) In the magnetic head according to claim 1, the nonmagnetic soft metal layer is made of a metal selected from gold, silver, and aluminum, or an alloy containing these metals as a main component, or an alloy of these metals as a main component. A magnetic head characterized in that it is formed from a laminate of two or more metals selected from the group of metals, or a laminate of these metals and another substance. (3) In the magnetic head according to claim 1, the thickness of the non-magnetic soft metal layer is 0.1 μm to 3 μm.
A magnetic head characterized by being formed.