JPH06111230A - Magnetic head - Google Patents

Abstract

PURPOSE:To suppress the generation of a pseudo gap by constituting an oxide magnetic body in the vicinity of a part where half bodies of a magnetic core having a metallic magnetic thin film are wound only of a polycrystal body. CONSTITUTION:The magnetic head is almost symmetric via a non-magnetic body 3 as a magnetic gap. A metallic magnetic thin film 1 is formed at the side of a magnetic core 2 of an oxide magnetic body where the magnetic gap is formed. The magnetic core 2 is comprised of a pair of half bodies. The metallic magnetic thin films 1 are butted via the non-magnetic body 3 and reinforced by a non-magnetic glass material 4 at the lateral side thereof, thereby constituting an annular magnetic core. A winding 5 is provided along a face of the magnetic core approximately parallel to a confronting recording medium. The oxide magnetic body in the vicinity of the part where the winding 5 is provided in the half bodies of true magnetic core is constituted of a polycrystal body 2a alone, and the oxide magnetic body except in the vicinity of the part of the winding 5 has a single crystal body 2b bonded at the side of the polycrystal body 2a where the magnetic gap is formed. Therefore, a pseudo gap is hard to generate.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a VTR, DAT, HDD
The present invention relates to a magnetic head used in a magnetic recording / reproducing apparatus such as the above.

[0002]

2. Description of the Related Art In a magnetic recording / reproducing apparatus such as a VTR, it is desired to improve temporal recording density (higher frequency band) and spatial recording density (narrow track, shorter wavelength). In order to realize this, it is premised that a magnetic head with a narrow gap and a narrow track width is placed close to a high coercive force medium capable of short-wavelength recording, and electromagnetic signals are input and output while both are traveling relatively at high speed. Becomes

In such a high-density recording magnetic head, as shown in FIG. 9, most of the magnetic core is composed of an oxide magnetic material 2 having excellent high frequency characteristics, and a high gap is provided at the gap abutting portion of the core. A head having a MIG (metal-in-gap) structure in which the metal magnetic thin film 1 having a saturation magnetic flux density is arranged is effective.

However, in the MIG head as shown in FIG. 9, the boundary surface between the oxide magnetic material and the metal magnetic thin film acts as a pseudo gap, and the frequency characteristic curve of the recording / reproducing output is shown in FIG. Swells are likely to appear. In addition, the oxide magnetic material that constitutes the main part of the magnetic core of the MIG head easily induces noise, which is so-called sliding noise, which is generated due to high-speed sliding between the magnetic head and the recording medium during signal reproduction.

Japanese Unexamined Patent Publication (Kokai) No. 1-133204 discloses, as a means for solving the above-mentioned pseudo-gap problem in an MIG head, a gap of an oxide magnetic material having a perfect crystal plane exposed by a treatment such as mirror polishing, phosphoric acid etching and reverse sputtering. It is disclosed that a metal magnetic thin film is formed on the formation surface via a heat resistant thin film having a thickness of several nm.

Japanese Unexamined Patent Publication No. 2-139704 discloses an oxide magnetic material as a magnetic core constituting member of an MIG head.
A polycrystalline body is more advantageous than a single crystal body in terms of reducing the sliding noise, but it is difficult to prevent the pseudo-gap and the flatness of the gap forming surface that affects the recording / reproducing output. Discloses that a single crystal body is more advantageous.

Japanese Patent Laid-Open No. 63-184903 discloses a recording medium for a polycrystalline body 2a for the purpose of complementing the above-mentioned disadvantages of the single crystalline oxide magnetic material alone or the polycrystalline oxide magnetic material alone. There is disclosed an MIG head having a single crystal body 2b arranged on the opposite surface side as shown in FIG.
The composite oxide magnetic body in the G head has to be manufactured by alternately laminating and bonding a plurality of single crystal bodies and polycrystal bodies, and is not said to be excellent in mass productivity in terms of dimensional accuracy and manufacturing man-hours. I want to.

[0008]

On the basis of the above-mentioned conventional techniques, the present invention has a large recording / reproducing output, a pseudo gap does not occur, a sliding noise is small, and the MIG head is excellent in mass productivity. Clarify the structure of.

[0009]

In a magnetic head according to the present invention, a metal magnetic thin film is formed on the gap forming surface side of at least one magnetic core half of a pair of magnetic core halves made of an oxide magnetic material. The metal magnetic thin film and the other half of the magnetic core are butted against each other via a non-magnetic material serving as a magnetic gap to form an annular magnetic core, and the annular magnetic core is along a surface substantially parallel to the recording medium facing surface. In the magnetic head in which the winding is applied, the oxide magnetic body near the portion of the magnetic core half on which the metal magnetic thin film is formed is formed of only a polycrystalline body. The oxide magnetic body other than the vicinity of the portion of the half body where the winding is applied is characterized by having a structure in which a single crystal body is joined to the gap forming surface side of the polycrystalline body.

[0010]

The magnetic head of the present invention exhibits the following operational effects with respect to the above-mentioned problems relating to recording / reproducing output, pseudo gap, sliding noise, mass productivity and the like.

Regarding the recording / reproducing output, when the oxide magnetic material portion gap forming surface of the MIG head is made of polycrystal, the phosphoric acid etching treatment as the measure for preventing the pseudo gap disclosed in the above-mentioned JP-A-1-133204 is performed. When applied, unevenness is generated on the gap forming surface due to the difference in etching rate of various crystal grains having different crystal orientations, and unevenness also appears on the surface of the metal magnetic thin film formed on the gap forming surface to make it clear. Although the gap cannot be formed and the recording / reproducing output is reduced, in the MIG head of the present invention, since the gap forming surface side of the composite oxide magnetic body is composed of a single crystal, a clear gap is obtained even if the phosphoric acid etching treatment is performed. Is formed.

With respect to the pseudo-gap problem, the M of the present invention
In the IG head, the gap forming surface side of the complex oxide magnetic body is composed of a single crystal, and therefore the pseudo gap prevention measures disclosed in the above-mentioned JP-A-1-133204, such as phosphoric acid etching treatment, are effective without adversely affecting the other. Act on.

Regarding the sliding noise, the mechanism for generating the sliding noise is that the minute elastic vibrations generated by high-speed relative running between the magnetic head and the recording medium are generated from the surface of the magnetic head facing the recording medium to the winding of the magnetic core. It is said that the microscopic vibration of the magnetic flux propagates to the applied portion and the microelastic vibration exerts an inverse magnetostriction effect on the magnetic core material in the winding part, and thus the microvibration of the magnetic flux is generated, and is induced in the winding by the microvibration of the magnetic flux. Since the mechanism is the main, and the contribution of the mechanism that the minute vibration of the magnetic flux generated in the vicinity of the recording medium facing surface is propagated to the winding portion and induced, is a secondary one. The occurrence of sliding noise is small unless a single crystal magnetic body having a large inverse magnetostriction effect as compared with a physical magnetic body is arranged even in the winding portion.

In terms of mass productivity, when an attempt is made to knit a process in which a large number of gap abutting portions of a magnetic head and longitudinally and laterally aligned magnetic core half members are abutted and joined, and then the magnetic heads are cut one by one, The above-mentioned JP-A-6
The composite oxide magnetic body in the MIG head of 3-184903 must have a plurality of single crystal bodies and polycrystal bodies alternately laminated and bonded. However, in the present invention, one single crystal body and one polycrystal body are bonded to each other. Since it suffices to prepare the composite oxide magnetic body bonded to each other, it is advantageous in terms of dimensional accuracy, manufacturing man-hours, and the like.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a magnetic head according to the present invention is shown in FIGS. FIG. 1 is an external perspective view of the magnetic head, FIG. 2A is a plan view of the recording medium facing surface of the magnetic head of FIG. 1, and FIG. 2B is a sectional view taken along the line AB of FIG. 2A. That is, it is a sectional view of the main magnetic path constituting surface of the magnetic head.

The magnetic heads shown in FIGS. 1 and 2 have a substantially symmetrical structure on both sides of the non-magnetic body 3 serving as a magnetic gap, and a gap is formed between a pair of magnetic core halves 2 made of an oxide magnetic body. A metal magnetic thin film 1 is formed on the surface side, the metal magnetic thin films are butted against each other via a non-magnetic body 3 serving as a magnetic gap, and a non-magnetic glass material 4 arranged on the side surface thereof.
A magnetic head in which an annular magnetic core is formed by reinforcement joining by means of, and a winding 5 is provided along a surface of the annular magnetic core substantially parallel to the surface of the annular magnetic core facing the recording medium, wherein the metal magnetic thin film is formed. The oxide magnetic body near the portion of the magnetic core half where the winding is applied is composed only of the polycrystalline body 2a, and the oxide magnetic body other than near the portion where the winding of the magnetic core half is provided. Is a single crystal body 2b on the gap forming surface side of the polycrystalline body 2a.
Have a joined structure.

As a material for the oxide magnetic body 2, Mn-Zn ferrite is suitable, which is relatively easy to produce a single crystal body and a polycrystalline body and has a relatively large saturation magnetic flux density. The composition of the Mn-Zn ferrite is "52 to 56 mol% F, which is generally used for magnetic heads of a simple ferrite type.
"e ₂ O ₃ -22 to 30% MnO-remaining ZnO" and the like are adopted, but they have been shunned in the past due to the fact that sliding noise is likely to occur while having higher magnetic permeability and higher saturation magnetic flux density. _{~56mol% Fe 2 O 3 -30~38%} MnO
The composition of "remaining ZnO" is also suitable for the magnetic head of the present invention having a low sliding noise structure.

For the polycrystalline portion 2a of the oxide magnetic material, a so-called high-density ferrite in which ordinary sintered ferrite is subjected to hot isostatic pressure treatment to lower the porosity and the crystal grains are made finer is adopted. To be done.

Regarding the crystal orientation of the oxide magnetic single crystal part 2b, the "gap forming surface {100}, the recording medium facing surface {11" recommended in JP-A-1-133204 is used.
0} ”or the like is adopted, but the inventor of the present application defines“ gap formation surface {110}, recording medium facing surface {100} ”as an azimuth with high symmetry with less occurrence of pseudo gap, that is, with small surface index. , "Gap forming surface {111}, recording medium facing surface {110}", "gap forming surface {21}
1}, recording medium facing surface {111} "," gap forming surface {210}, recording medium facing surface {521} "," gap forming surface {521}, recording medium facing surface {210} "and the like are preferable. That is also found experimentally.

The metal magnetic thin film 1 has a high magnetic permeability,
Fe-Al-Si-based polycrystalline alloy with high saturation magnetic flux density, Fe
A -Zr-N-based fine crystal alloy, a Co-Zr-based amorphous alloy, or the like is adopted.

The manufacturing process of the magnetic head shown in FIGS. 1 and 2 will be described with reference to FIGS.

Step corresponding to FIG. 3A: one polycrystalline oxide magnetic substrate 2a and one single crystalline oxide magnetic substrate 2b are provided.
Prepare the two pieces, and polish both surfaces by mirror polishing and butt 10
The composite oxide magnetic substrate 2 is obtained by performing hot pressure treatment at 00 to 1500 ° C. at several kg / cm ² .

Step corresponding to FIG. 3B: After the single crystal body side of the composite oxide magnetic substrate 2 is mirror-polished and subjected to pseudo-gap prevention treatment such as phosphoric acid etching, reverse sputtering and heat resistant thin film formation. , A metal magnetic thin film 10 having a thickness of several μm
And a gap spacer thin film having a thickness of several hundreds nm (not shown)
Are deposited by a sputtering method or the like.

FIGS. 4 (c) to 4 (f) show changes in the shape of the side faces P and Q in FIG. 3 (b) as the manufacturing process progresses.

Step corresponding to FIG. 4C: A portion 1 of the metal magnetic thin film and the gap spacer thin film to be left as a gap butting portion is covered with a photoresist, and the other portions are removed by etching by an ion beam method or the like. After etching, the photoresist is washed off with an organic solvent or the like.

Step corresponding to FIG. 4D: Track groove processing 6, winding groove processing 7, and glass rod insertion groove processing 8 are performed on the oxide magnetic material portion exposed on the substrate surface by the ion beam etching in the previous step. Give. In order to embody the features of the present invention, the depth of the winding groove is set to a depth at least reaching the polycrystal part of the composite oxide magnetic body, and more preferably, the single crystal part of the composite oxide magnetic body. It is necessary to make the depth more than twice the thickness. If the winding groove is too shallow, the MIG head in which the single crystal oxide magnetic body 2b is arranged is also formed in the winding portion as shown in FIG. 12, and the effect of the present invention cannot be expected.

Step corresponding to FIG. 4E: The first magnetic core half member substrate obtained through the steps up to this point, and the first rod except that the glass rod insertion groove is not formed
The magnetic core half body member substrate and the second magnetic core half body member having the same structure are abutted against each other in a pair, and the glass rod 40 is inserted into the glass rod insertion groove, and heated and heated.

Step corresponding to FIG. 4 (f): The glass heated and heated until it melts flows into the track groove portion 46 and the winding groove tip portion 47 due to the capillary phenomenon, and the pair of magnetic core half members. Are joined and integrated. The bonded integrated product is cut along the glass groove and the track groove, and the surface facing the recording medium is polished to obtain a magnetic head chip.

Other examples of the magnetic head according to the present invention are shown in FIGS. In each drawing, (a) is a plan view of the surface of the magnetic head facing the recording medium, and (b) is a cross-sectional view taken along the line AB of (a), that is, a cross-sectional view of the main magnetic path forming surface of the magnetic head.

FIG. 5 shows an example in which a metal magnetic thin film is formed also on the inner wall surfaces of the track width regulating groove and the winding groove. Since the metal magnetic thin film is a material that hardly induces sliding noise, the winding hole Even if it adheres to the inner wall surface, it does not impair the effects of the present invention.

FIGS. 6 and 7 show an example in which a metal magnetic thin film is formed only on one magnetic core half body. In this case, a single magnetic core half body causes sliding noise on the winding portion of the other magnetic core half body. In order to prevent the crystalline oxide magnetic body from being arranged, the single crystalline oxide magnetic body 2b in the winding portion of the magnetic core half body in which the metal magnetic thin film is not formed is removed by winding groove processing in FIG. In No. 7, the magnetic core half body in which the metal magnetic thin film is not formed is composed only of the polycrystalline oxide magnetic body 2a.

FIG. 8 shows an example in which the present invention is applied to a so-called tilted MIG head in which the boundary surface between the oxide magnetic bodies 2a and 2b and the metal magnetic thin film 1 is tilted with respect to the gap abutting surface.

[0033]

The magnetic head according to the present invention is suitable for high-density magnetic recording because it has an MIG structure. Since the metal magnetic thin film deposition base is made of a single-crystal oxide magnetic material, a pseudo gap hardly occurs. Since the oxide magnetic material in the vicinity of the portion where the winding is applied is composed of only a polycrystalline material, sliding noise is less likely to occur, and it is only necessary to join one polycrystalline and single crystalline oxide magnetic material substrate. Since it can be manufactured using a composite substrate, it has excellent mass productivity.

[Brief description of drawings]

FIG. 1 is an external perspective view of a magnetic head according to a first embodiment of the present invention.

FIG. 2A is a plan view of a surface facing a recording medium, and FIG. 2B is a sectional view of a magnetic path constituting surface of a magnetic head according to a first embodiment of the present invention.

FIG. 3 is an explanatory diagram (first half) of a manufacturing process of the magnetic head according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram (second half) of the manufacturing process of the magnetic head according to the first embodiment of the present invention.

5A is a plan view of a surface facing a recording medium, and FIG. 5B is a sectional view of a magnetic path constituting surface of a magnetic head according to a second embodiment of the present invention.

FIG. 6A is a plan view of a surface facing a recording medium and FIG. 6B is a sectional view of a magnetic path constituting surface of a magnetic head according to a third embodiment of the present invention.

FIG. 7A is a plan view of a recording medium facing surface of a magnetic head according to a fourth embodiment of the present invention, and FIG. 7B is a sectional view of a magnetic path constituting surface.

FIG. 8A is a plan view of a recording medium facing surface of a magnetic head according to a fifth embodiment of the present invention, and FIG.

FIG. 9 is an external perspective view of a first conventional magnetic head.

FIG. 10 is a frequency characteristic curve diagram for explaining a pseudo gap problem in a conventional magnetic head.

FIG. 11 is an external perspective view of a second conventional magnetic head.

12A is a plan view of a recording medium facing surface of a comparative magnetic head, and FIG. 12B is a cross-sectional view of a magnetic path forming surface.

[Explanation of symbols]

 1 Metal Magnetic Thin Film 2 Oxide Magnetic Material 2a Polycrystalline Oxide Magnetic Material 2b Single Crystal Oxide Magnetic Material 3 Non-Magnetic Material for Magnetic Gap 4 Glass for Joining Reinforcement 5 Winding

Claims (1)

[Claims] 1. A metal magnetic thin film is formed on a gap forming surface side of at least one magnetic core half of a pair of magnetic core halves made of an oxide magnetic material, and the metal magnetic thin film and the other magnetic core half are formed. A magnetic head in which an annular magnetic core is formed by being abutted against a body via a non-magnetic body that serves as a magnetic gap, and a winding is applied along a plane substantially parallel to the recording medium facing surface of the annular magnetic core, A portion of the magnetic core half on which the metal magnetic thin film is formed, in the vicinity of the portion on which the winding is applied, is made of only a polycrystalline material, and a portion of the magnetic core half on which the winding is applied. A magnetic head characterized in that the oxide magnetic material other than the vicinity has a structure in which a single crystal body is joined to a gap forming surface side of a polycrystalline body.