JPS61255512A - Composite type magnetic head - Google Patents

Abstract

PURPOSE:To eliminate an erasing head and to improve reproducing efficiency by forming a thin film layer having a satd. magnetic flux density lower than the satd. magnetic flux density of a material constituting a core member to the butt part of a gap and expanding the gap length to the opposed surfaces of the core member in the stage of recording. CONSTITUTION:The core halves 1a, 1b are formed of Mn-Zn ferrite and are formed with slopes 7 on both sides of opposed surfaces 6 having a prescribed track width (w). The thin film layer 3 is formed of the magnetic material such as, for example, Fe20Ni20Co38Si8B14 having the satd. magnetic flux density lower than the satd. magnetic flux density of the Mn-Zn ferrite constituting the core halves 1a, 1b and the magnetic permeability higher than the magnetic permeability thereof. The layer 3 is formed by sputtering or the like on the opposed surfaces 6 and slopes 7 of the core halves 1a, 1b. The gap 4 is formed by sputtering of a nonmagnetic material such as SiO2. The layer 3 and the gap 4 are preferably formed respectively to about 1.5-2.0mum, 0.3-0.5mum to improve recording/reproducing efficiency.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a composite head that combines the functions of a recording head for writing information on a magnetic recording medium and the function of a reproducing head for reading information recorded on a magnetic recording medium into one. This relates to a type magnetic head.

[Background technology]

For example, in magnetic recording devices such as floppy disk drives and video tape recorders, when the recording head and the reproducing head are arranged separately, the angle l! ll! In order to solve the problems of 1 and track adjustment, a composite magnetic head is used in which the functions of both heads are combined into one.

Incidentally, there is the following relationship between the gap length of a magnetic head, recording efficiency, and reproduction efficiency.

In other words, when writing information to a recording medium, using a magnetic head with a wide gap length increases recording efficiency and enables deep writing.On the other hand, when reading information recorded on a recording medium, using a magnetic head with a wide gap length Reproduction efficiency is higher when a magnetic head with a narrower length is used. On the other hand, there is a relationship between the gap length and the recording density characteristics of a magnetic head, such that the wider the gap length, the lower the recording density, and the narrower the gap length, the higher the recording density. For this reason, only 1
In a composite magnetic head that has two gap sections and is configured to function as a recording head or a reproduction head, recording efficiency can be improved by setting a wide gap length. However, on the other hand, the reproduction efficiency and recording density will decrease.On the other hand, if the gap length is set narrow, the reproduction efficiency and recording density characteristics will improve, but! ii) There is a contradictory problem in that the recording efficiency decreases.

Regarding this point, conventionally, from the standpoint of emphasizing recording density characteristics,
This is in the direction of narrowing the gap length. However, narrowing the gap length causes a decrease in recording efficiency as described above, resulting in the following problems.

That is, when a metal tape with high coercive force is used as a recording medium, it is not possible to obtain the magnetic field necessary for recording on the tape, and the recording becomes shallow and becomes unstable.

In addition, deep recording is not possible in magnetic recording devices such as floppy disk drives that do not have an erasing head and repeatedly record new information by overwriting new information from above the existing green area. , problems such as previously recorded information not being completely erased are likely to occur.

In order to prevent such problems, conventionally, a thin film of a metal magnetic material having a higher saturation magnetic flux density and magnetic permeability than the magnetic material constituting the core member is formed at the gap abutting part, and the saturation magnetic flux density of the gap part is reduced. A composite magnetic head is known that increases the recording efficiency and compensates for the decrease in recording efficiency due to the narrowing of the gap.

However, the rate of increase in recording efficiency by implementing the above measures is almost determined by the ratio of the saturation magnetic flux density of the core member and the saturation magnetic flux density of the metal magnetic material formed in the gap abutting portion, so the recording efficiency can be adjusted arbitrarily. Not only can you not choose.

There is a drawback that the characteristics of the magnetic head become non-uniform. For example, when Mn-Zn ferrite is used as the core member and amorphous is used as the metal magnetic material with high saturation magnetic flux density and high magnetic permeability, the saturation magnetic flux density of Mn-Zn ferrite is 3,000 to 3.400 Gauss. and
The saturation magnetic flux density of amorphous is 5,000 to 7,00
0 Gauss (Japanese Patent Publication No. 51-73920), the recording efficiency of this composite magnetic head is.

It can be seen that the non-uniformity is approximately 1.5 to 2.3 times greater than that using a core material made of only Mn--Zn ferrite.

[Purpose of the invention]

The present invention solves the problems of the conventional composite magnetic head described above, and has high recording efficiency and high reproduction efficiency.

Another object of the present invention is to provide a composite magnetic head with excellent recording density characteristics.

[Summary of the invention]

In order to achieve the above object, the present invention provides a composite magnetic head that combines the functions of a recording head for writing information on a magnetic recording medium and the function of a reproducing head for reading information recorded on a magnetic recording medium into one. A thin film of a magnetic material having a lower saturation magnetic flux density and higher magnetic permeability than the magnetic material constituting the core half is formed on the opposing surface of the core half,
The core halves are coupled to the gap abutting portion formed on the surface of this thin film via a gap member, and the opposing surfaces of the core halves have a saturation magnetic flux density higher than that of the magnetic material constituting the core halves. A thin film of a metal magnetic material with high magnetic permeability is formed, and the saturation magnetic flux density is lower than that of the magnetic material constituting the core half on the surface of the thin film of the metal magnetic material, and
The present invention is characterized in that a thin film of a magnetic material with high magnetic permeability is formed, and the core half is coupled to a gap abutting portion formed on the surface of this thin film via a gap member.

〔Example〕

FIG. 1 is a perspective view showing a first embodiment of a composite head according to the present invention, and FIG. 2 is a plan view of the composite magnetic head shown in FIG.

In these figures, la and lb are core halves.

2 is a winding window formed in the core halves 1a and lb.

3 is a thin film layer of magnetic material formed on the opposing surfaces of the core halves 1a and 1b, 4 is a gap provided between the abutting surfaces of the thin film layers 3 and 3, and 5 is the core half body that is abutted together. 9 shows a non-magnetic filler that fills a concave portion formed on the side surface. The core halves 1a and 1b are made of Mn-Zn ferrite, and have inclined surfaces on both sides of the opposing surface 6 having a predetermined track width W. 7 is formed. The thin film layer 3 is made of, for example, F
It is formed of a magnetic material such as ezoNi or zoCoSip B+4, which has a lower saturation magnetic flux density and higher magnetic permeability than the Mn-Zn ferrite that constitutes the core halves 1a and lb. This thin film layer 3 covers the core half 1a.
, lb by a known thin film forming means such as sputtering. The gap 4 may be formed of a non-magnetic material such as SiO by known thin film forming means such as sputtering, similar to the thin film layer 3.
The thickness can be selected arbitrarily depending on the design.

Considering recording efficiency, reproduction efficiency, and recording density, the thickness of the thin film layer 3 is approximately 1.5 μm to 2.0 μm, and the thickness of the gap 4 is 0.3 μm to 0.5 μIn.
The condition is good.

The composite magnetic head of the first embodiment includes a core half 1a,
On the facing surface 6 of lb, the core half 1a and Mn constituting lb
-Since the thin film layer 3 is formed with a lower saturation magnetic flux density and higher magnetic permeability than Zn ferrite, the thin film layer 3 is
is magnetically saturated and the gap length is substantially expanded to the length t of the abutting portion of the core halves 1a and lb formed of Mn-Zn ferrite, which improves the recording efficiency. During reproduction, since the magnetic flux density from the recording medium is low, the thin film layer 3 is not magnetically saturated.

The gap length will be the original thickness of gap 4.

There is no reduction in regeneration efficiency. In this case, the thin film layer 3 is made of a material with high magnetic permeability.

The magnetic resistance is small, and the presence of the thin film layer 3 does not reduce the reproduction efficiency.

FIG. 3 is a perspective view showing the second embodiment of the present invention, and FIG.
r! ! J is a plan view of the magnetic head in FIG.
Regarding the same parts as in FIG.

They are indicated by the same symbols.

In these figures, 8 is a metal layer formed on the opposing surface 6 and the inclined surface 7 of the core halves 1a and lb, which has a lower saturation magnetic flux than the M n -Zn ferrite that constitutes the core halves 1a and lb. A thin film of a metal material having high density and magnetic permeability, such as sendust or amorphous, is formed by a known thin film forming means. Reference numeral 99 is a thin film layer formed on the surface of the metal material N8, and is a thin film layer formed on the surface of the metal material N8. Fezo N1zo Coyg Sir
Mn-Zn forming core halves 1a and lb such as B+4
A magnetic material having a lower saturation magnetic flux density and higher magnetic permeability than ferrite is formed by known thin film forming means.

In the composite magnetic head of the second embodiment, a thin film layer with low saturation magnetic flux density and high magnetic permeability is formed at the gap abutting portion, so that during recording, the thin film layer 9 is magnetically saturated and the gap length is substantially reduced. Core half 1 made of upper Mn-Zn ferrite
The length of the abutting portion of a and lb is increased to t, and recording efficiency can be improved. In this case, core halves 1a, lb
Since a thin film layer 8 of a metal magnetic material is formed on the opposing surface 6 of the
A magnetic field with a sharp distribution is generated from the gap portion, making it possible to further improve recording efficiency. On the other hand, during reproduction, since the magnetic flux density from the recording medium is small, the thin film layer 9 is not magnetically saturated, and the original thickness t of the narrow gap 4 is reduced.
functions as a gap length, resulting in high regeneration efficiency. In this case, since the thin film layer 9 is formed of a material with high magnetic permeability, the magnetic resistance is small, and the presence of the thin film layer 9 does not reduce the reproduction efficiency.

Note that the above embodiments show examples in which Mn-Zn ferrite is used as the core member and Fezo N1zo Coqg Si2 B+4 is used as the magnetic material with low saturation magnetic flux density and high magnetic permeability. is core half 1
The point is that a Wl film layer made of a magnetic material having a lower saturation magnetic flux density and higher magnetic permeability than the material constituting the core half is provided on the facing surface 6 of the core halves, and the materials used are limited to the above. It's not a thing. Further, for the same reason, the overall shape of the composite magnetic head is not limited to that shown in the drawings.

〔Effect of the invention〕

In the composite magnetic head of the present invention, a thin film layer having a saturation magnetic flux density lower than that of the material constituting the core member is formed in the gap abutting portion, and during recording, the gap length is substantially expanded to the opposing surface of the core member. As a result, recording efficiency is increased and deep writing becomes possible. Therefore, the recording medium has high retention power.

The present invention can also be applied to a magnetic recording device that does not include an erasing head and performs re-recording by overwriting new information over recorded information. Furthermore, since the gap length during reproduction is the original narrow gap length, the reproduction efficiency is high and the demand for higher density can be satisfied.

Further, in the composite magnetic head of the present invention, a thin film layer having a saturation magnetic flux density lower than that of the material constituting the core member is formed at the gap abutting portion, and this thin film layer functions as a gap during recording. By appropriately adjusting the thickness of this thin film layer in advance, the gap length during recording can be adjusted to an arbitrary value. Therefore, compared to the conventional composite magnetic head, which compensates for the decrease in recording efficiency due to the narrowing of the gap length by forming a thin film layer with high saturation magnetic flux density at the gap butt portion, the composite magnetic head Practicality and versatility can be greatly improved.

[Brief explanation of the drawing]

The accompanying drawings show embodiments of the present invention, in which
The figure is a perspective view of the composite magnetic head of the first embodiment, FIG. 2 is a plan view of the composite magnetic head shown in FIG. 1, and FIG.
FIG. 4 is a perspective view of the composite magnetic head of the embodiment, and FIG. 4 is a plan view of the composite magnetic head shown in FIG. 3. la, Ib: core half, 2: winding window, 3: thin film layer, 4:
Reproduction gap, 5; non-magnetic filler, 6: opposing surface, 7:
Inclined surface, 8: Metal material layer, 9: Thin film layer

Claims (2)

[Claims] (1) In a composite magnetic head in which the function of a recording head for writing information on a magnetic recording medium and the function of a reproducing head for reading information recorded on a magnetic recording medium are combined into one, the opposing surfaces of the core halves are , a thin film of a magnetic material having a lower saturation magnetic flux density and higher magnetic permeability than the magnetic material constituting the core half is formed, and a non-magnetic gap member is provided at the gap abutting portion formed on the surface of this thin film. A composite magnetic head characterized in that the core halves are connected via a composite magnetic head. (2) In a composite magnetic head in which the function of a recording head for writing information on a magnetic recording medium and the function of a reproducing head for reading information recorded on a magnetic recording medium are combined into one, the opposing surfaces of the core halves are , a thin film of metallic magnetic material having higher saturation magnetic flux density and magnetic permeability than the magnetic material constituting the core half is formed, and a saturation magnetic flux higher than that of the magnetic material constituting the core half is formed on the surface of this thin film of metallic magnetic material. low density,
A composite magnetic type characterized in that a thin film of a magnetic material with high magnetic permeability is formed, and the core half is coupled to a gap abutting portion formed on the surface of the thin film via a non-magnetic gap member. head.