JPH0533303U - Magnetic head - Google Patents

Abstract

(57) [Summary] [Object] To provide a magnetic head having an MIG structure capable of high output due to the magnetic permeability and high core efficiency of a magnetic film having a high saturation magnetic flux density. [Structure] The angle of the apex inclined portion 6 formed on the C-shaped ferrite cores 1 and 2 is set to 15 to 25 °, and the high saturation magnetic flux density magnetic thin films 3 and 4 are formed on the ferrite cores 1 and 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a magnetic head used for a hard disk drive, a VTR, a floppy disk drive, etc. for recording / reproducing information, and particularly to a high saturation magnetic flux density magnetic field at least on one side of a gap part sandwiched between two ferrites. The present invention relates to a magnetic head having an MIG structure formed with a thin film.

[0002]

[Prior Art]

 In recent years, recording media are required to have higher recording densities, and track widths of recording / reproducing tracks have been narrowed and recording linear densities have been improved. In a magnetic head compatible with a narrow track and a high recording linear density, the head output generally lowers and the resolution lowers. Therefore, in the magnetic head, it is necessary to improve the output in the high frequency band and improve the resolution. Specifically, a high saturation magnetic flux density magnetic material thin film is used in the gap portion as shown in FIG. A MIG structure head is often used. This makes it possible to make the leakage magnetic field near the main gap steep, improve the output in the high frequency band, and improve the resolution. The basic concept of the magnetic head having the MIG structure is described in Japanese Utility Model Publication No. 29-11642.

As shown in FIG. 5, a magnetic head having a MIG structure has a ring-shaped magnetic head in which a ferrite core 101 having a C-shaped cross section and a ferrite core 102 having an I-shaped cross section are joined via a gap member 103. Was configured.

On the bonding surface side of the ferrite cores 101 and 102, high saturation magnetic flux density magnetic thin films 105 and 104 such as metals such as sendust and permalloy and amorphous thin films are formed. The cap member 103 has a single-layer or laminated structure of low-melting glass such as lead glass or silica-lead glass-silica. The C-shaped ferrite core 101 is formed in the vicinity of the front gap portion FG on the side facing the recording medium in order to concentrate the magnetic flux in the C-shaped ferrite core 101 with respect to the joint surface of the front gap portion FG. As a result, an inclined portion having a spread of about 45 ° (apex angle θ3) was formed. Further, the upper surface portion of the magnetic head in which the C-shaped ferrite core 101 and the I-shaped ferrite core 102 are joined has a track portion whose width is narrowed according to the track width of the recording medium. ..

[0005]

[Problems to be solved by the device]

 Although the magnetic head of the MIG structure described above can improve the output in the high frequency band as compared with the magnetic head of the non-MIG structure which does not form the high saturation magnetic flux density magnetic thin films 104 and 105, it is still sufficient. Output has not yet been obtained. In addition to the adoption of the MIG structure, the output is improved by the number of turns of the coil wound around the ferrite core, the gap between the front gap FG and the recording medium when reproducing / recording information, and the optimum gap length. , The core efficiency and the like are obtained by optimization correlation. However, in the above-described conventional magnetic head having the MIG structure, the core efficiency, which is the characteristic of the magnetic head itself, is not yet sufficiently obtained. Is.

The present invention has been made in view of the above problems, and an object thereof is to improve the core efficiency by optimizing the shape of a ferrite core in a magnetic head having a MIG structure. As a result, it is to provide a magnetic head with improved core output.

[0007]

[Specific means for solving the problem]

 According to the present invention, in a magnetic head for recording / reproducing on / from a magnetic recording medium by contacting a pair of ferrite cores with each other via a gap member, the ferrite core is moved from a contact surface with the gap member to a corresponding contact surface. On the other hand, the magnetic head is characterized in that it spreads at an angle (apex angle) of 15 to 25 ° and that a high saturation magnetic flux density magnetic material film is formed on the contact surface side of each ferrite core. It is

[0008]

According to the present invention, by using a C-shaped ferrite core as a pair of ferrite core members and optimizing the apex angle, the magnetic resistance of the winding portion is reduced and the core efficiency is improved. .. Also, the magnetic angle of the magnetic path of the C ferrite core (apex angle) is set to 15 to 25 °, so that the magnetic characteristics of the high saturation magnetic flux density magnetic film are improved, and the leakage flux of the entire core of the magnetic head is minimized. A magnetic head with improved efficiency and overall improved output is achieved.

[0009]

【Example】

 The present invention will be described in detail with reference to the drawings. FIG. 1 is a side view of the magnetic head of the present invention, and FIG. 2 is an enlarged view of the front gap portion.

The magnetic head is composed of a pair of ferrites 1 and 2, a high saturation magnetic flux density magnetic thin film 3 and 4, and a non-magnetic thin film 3, and a magnetic medium recording medium (see FIG. A front gap FG is formed on the (not shown) side, and a back gap BG is formed on the opposite side.

The pair of ferrites 1 and 2 are made of single crystal or polycrystal ferrite and are formed in a C shape. The inclined portions 6 and 7 are formed so as to narrow the magnetic paths of the ferrite cores 1 and 2 toward the front gap FG side.

The high saturation magnetic flux density magnetic thin films 3 and 4 are made of a metal such as sendust or permalloy, or a magnetic thin film such as amorphous, and are attached to at least the surfaces of the ferrites 1 and 2 forming the front gap FG. ing.

The non-magnetic thin film 3 is composed of a single layer of lead glass or a laminated thin film of lead glass and silica glass, and acts as a main gap.

The central space of the ring-shaped magnetic head formed in this way becomes the winding portion 8, and the angle of the inclined portion 6 formed so as to widen with respect to the joint surface of the ferrite 1 of the front gap FG is This is called the apex angle θ1, and the angle of the inclined portion 7 with respect to the joint surface of the ferrite 2 is called the apex angle θ2.

As a concrete method of manufacturing a magnetic head, first, a high thickness of about 1.25 μm is provided on the joint surface side of the ferrite base material having a C-shaped cross section which becomes the ferrite 1 and on which the inclined portion 6 is formed. The saturated magnetic flux density magnetic thin film 3 is applied by a thin film technique such as sputtering, vapor deposition, or ion plating, and the non-magnetic thin film 5 having a single layer or a laminated structure is formed on the high saturated magnetic flux density magnetic thin film 3 by the above-mentioned thin film technique. About half of the thickness, for example 0.3 μm, is applied. Further, it is similarly formed on the ferrite base material having the C-shaped cross section which becomes the ferrite 2 and on which the inclined portion 7 is formed. Next, the two ferrite base materials are brought into contact with each other and heated to about 540 ° C., and the nonmagnetic thin films 3 are heat-welded and integrated. Next, the ferrite base material is integrated and sliced according to the thickness of the magnetic head to obtain the magnetic head shown in FIG. If necessary, the upper surface of the front gap FG side is subjected to track processing (not shown) having a width in a predetermined thickness direction corresponding to the track width of the recording medium.

As a result, the structure of the front cap FG is ferrite 1-high saturation magnetic flux density magnetic thin film 3-nonmagnetic thin film 5-high saturation magnetic flux density magnetic thin film 4-ferrite 2. The head is achieved.

In actuality, in order to record / reproduce information on / from a magnetic recording medium, the magnetic head is attached to a slider or the like, and the winding window 8 is used in either of the ferrite cores 1 and 2. The wire is wound a predetermined number of times.

When recording information on the magnetic recording medium, an electric signal corresponding to the write information is applied to the wire. In the ring-shaped magnetic head, magnetic paths are formed in the ferrites 1 and 2 and the high saturation magnetic flux density magnetic films 3 and 4, and a leakage magnetic flux is generated from the front gap FG. Information is written in the recording area of the magnetic recording medium by the leakage magnetic flux. It should be noted that reproduction is performed in the reverse operation, and the magnetic flux from the recording area of the magnetic recording medium is captured by the magnetic head to obtain information as an electric signal from the wire.

The present invention is particularly characterized in that the apex angles θ1 and θ2 are set to 15 to 25 °.

Depending on the apex angles θ1 and θ2, the magnetic permeability μ and the core efficiency of the high saturation magnetic flux density magnetic films 3 and 4 are greatly changed. Therefore, by setting the apex angles θ1 and θ2 to 15 to 25 °, the magnetic permeability μ of the high saturation magnetic flux density magnetic films 3 and 4 is improved, and the core efficiency is greatly improved.

The present inventor investigated the relationship between the magnetic permeability μ and the core efficiency of the high saturation magnetic flux density magnetic films 3 and 4 depending on the apex angles θ1 and θ2.

As a sample, the height of the core is 0.6 mm, the thickness is 0.15 mm, the depth of the front gap F G is 5 μm, the depth of the back gap BG is 0.12 mm, and the width of the winding window in the height direction is 0.35 mm. , Track width 10 μm, high saturation magnetic flux density magnetic films 3 and 4, sendust film thickness 2 μm, non-magnetic film 5 silica glass-lead glass-silica glass film thickness 0.4 μm, number of windings The magnetic head having 39 turns was used.

FIG. 3 shows the relationship between the magnetic permeability μ of the high saturation magnetic flux density magnetic film 3 and the apex angle θ1. As can be seen from the figure, the smaller the apex angle θ1, the higher the magnetic permeability μ. For example, when the apex angle θ1 exceeds 25 °, the magnetic permeability μ deteriorates. As a result, the magnetic resistance of the magnetic path increases, and the output drops significantly. It is considered that the change in the magnetic permeability μ due to the apex angle θ1 is due to the magnetic anisotropy due to the difference between the growth direction of the sendust which is the high saturation magnetic flux density magnetic film 3 and the magnetic flux direction flowing in the magnetic path.

Generally, the core efficiency can be expressed as η = Rg / (Rg + Rc), where core efficiency η, magnetic resistance Rg of the front gap portion, and magnetic resistance Rc of the magnetic path of the core portion. That is, when the magnetic resistance Rc of the magnetic path increases, the core efficiency η tends to decrease. The relationship between the core efficiency and the apex angle θ1 is shown in FIG. As can be seen from the figure, the core efficiency has a peak at an apex angle θ1 of 20 °. When the core efficiency is 0.7 or less, only an output comparable to that of the conventional product can be obtained, and it cannot be used as a magnetic head of a recording medium for higher density recording. Therefore, in the present invention, the apex angle θ1 is set to 15 to 25 ° in order to obtain the core efficiency of 0.75 or more. The same result is obtained for the apex angle θ2.

The magnetic head of the present invention in which the apex angles θ1 and θ2 are selected to be 20 °, respectively, has a core efficiency of 0.76 and a reproduction output of 0.25 mV, which is a high output magnetic head. Incidentally, in the conventional magnetic head whose apex angle shown in the figure was set to 45 °, the core efficiency was 0.70 and the reproduction output was 0.22 mV.

Further, in the above-mentioned magnetic head, the high saturation magnetic flux density magnetic thin films 3 and 5 are formed on the two C-shaped ferrite cores 1 and 2, respectively. This is because the shape of the leakage magnetic flux is greatly influenced by the shape of the inclined portions 6 and 7, but if the inclined portions 6 and 7 are formed on both cores 1 and 2, the shape of the leakage magnetic flux is normally distributed. The magnetic recording medium can be formed into a rectangular shape, and it becomes easy to cope with higher frequencies of the magnetic recording medium.

In the embodiment, the high saturation magnetic flux density magnetic thin films 3 and 5 have the same thickness, but even if one high saturation magnetic flux density magnetic thin film is thicker than the other high saturation magnetic flux density magnetic thin film. I do not care. Further, the magnetic head having the above-mentioned MIG structure is widely used for a hard disk drive, a VTR, a floppy disk drive by itself or by being joined with a sliding material.

[0028]

[Effect of the device]

 In the present invention, in the magnetic head having the MIG structure, the apex angle formed on the ferrite core is set to 15 to 25 °. Therefore, the magnetic permeability of the high saturation magnetic flux density magnetic thin film is sufficiently high, and the core efficiency is further increased. As a result, a magnetic head with high reproduction output can be obtained.

[Brief description of drawings]

FIG. 1 is a side view showing a magnetic head of the present invention.

FIG. 2 is an enlarged view of a front gap portion of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between an apex angle and a magnetic permeability μ of a high saturation magnetic flux density magnetic film.

FIG. 4 is a characteristic diagram showing a relationship between an apex angle and core efficiency.

FIG. 5 is a side view showing a conventional magnetic head having an MIG structure.

[Explanation of symbols]

 1, 2 ・ ・ ・ ・ Ferrite cores 3, 4 ・ ・ ・ High saturation magnetic flux density magnetic thin film 5 ・ ・ ・ ・ Non-magnetic thin film 6, 7 ・ ・ ・

Claims (1)

[Scope of utility model registration request] 1. A magnetic head for recording / reproducing on / from a magnetic recording medium, wherein a pair of ferrite cores are in contact with each other via a gap member, wherein the ferrite core is in contact with a corresponding contact surface from a contact surface with the gap member. And a magnetic material film having a high saturation magnetic flux density is formed on each contact surface side of each ferrite core.