JPH06295409A - Magnetic head - Google Patents

Abstract

PURPOSE:To improve an offtrack characteristic and to decrease inductance by forming magnetic metallic thin films of a material having the saturation magnetic flux density higher than saturation magnetic flux density of magnetic cores and thinly working the thickness of the magnetic cores in such a manner that the width of recording is narowed. CONSTITUTION:This magnetic head is a both film type metal-in-gap magnetic head having the magnetic metallic thin films 3, 4 on the butt surfaces of the I core and the C core. The entire part of the magnetic cores is thinly worked to the same thickness as a track width TW in order to narrow the track width to obtain high-density recording. The second magnetic metallic thin films 1, 2 are arranged on the flanks of the magnetic cores including a winding window for passing conductors to excite the magnetic head. As a result, the thin magnetic cores are capable of delivering magnetomotive force toward a magnetic gap without inducing magnetic saturation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double film type metal-in-gap magnetic head used in a magnetic recording device.

[0002]

2. Description of the Related Art A magnetic head used in a magnetic recording apparatus has a pair of magnetic cores cut out from ferrite butted to each other in order to form a magnetic gap for recording and reproducing as the apparatus becomes smaller and has a larger capacity. A ring head was used. In addition, the magnetic recording medium will have a high coercive force in order to realize a small size and a large capacity, and the magnetic head will be provided with a magnetic metal thin film layer in the magnetic gap for the purpose of providing the ability to record on the medium having a high coercive force. This type of magnetic head is now widely used as the metal-in-gap type. Nishiyama, T, et al; “A Dou
ble Sided Metal-In-Gap For 150Mb / in Recording ",
The magnetic metal thin film arranged in the magnetic gap as shown in IEEE Trans Magn. MAG-28, pp, 2632 (1992) is arranged on the gap facing surfaces of both the I core and the C core so that the magnetic gap during recording is increased. The generated recording magnetic field is very strong at the center of the magnetic gap, and its rising speed is fast.
That is, there is an advantage that a strong and sharp magnetic field can be generated, and its effective utilization is expected. Although it is desired to further increase the recording density in the future, one recording, that is, magnetization, recorded on the magnetic recording medium, which is called 1 bit, shortens the length of 1 bit (shorter bit), 1 This is done by narrowing the bit width (making it into a fox track).
Therefore, in order to shorten the bit length, the non-magnetic portion is thinned when the IC cores are butted to each other to form the magnetic gap, and the magnetic gap on one side or both sides of the side surface of the magnetic core is reduced to narrow the track. A narrow and sharp recording magnetic field is obtained in the vicinity of the magnetic gap by narrowing the tip portion including it into a step shape.

[0003]

The double-layered metal-in-gap magnetic head is a development of a ring-shaped magnetic head made of a bulk magnetic material. Therefore, a certain volume is required so that the portion provided with the winding for exciting the magnetic head during recording is not magnetically saturated. On the other hand, as described above, as the magnetic recording density increases, it is necessary to process the magnetic gap portion thinly (step processing) to narrow down the magnetic flux generated in the excitation winding. Not only is the processing accuracy of step processing strict, but there are still problems with the method.
Also, it is thought that the magnetic flux generated in the excitation part may leak out of the magnetic material in the step part due to the narrow magnetic path of the same material (often ferrite), and the magnetic flux may not converge efficiently. . In an attempt to pursue magnetic recording with a narrow track width, magnetic thin films and non-magnetic thin films that are alternately laminated and supported by a non-magnetic substrate are butted against each other as a magnetic core (see, for example, JP-A-64-37705).
Etc.) method is disclosed. However, when the non-magnetic substrates are butted to each other to form a magnetic gap, there is a problem that the relative position between the magnetic core halves and the misalignment of the portion containing the magnetic material occur.

[0004]

According to the present invention, an I-shaped core and a C-shaped core are butted against each other in order to form a recording / reproducing magnetic gap of a magnetic head used for magnetic recording.
C. In a double-film type metal-in-gap magnetic head in which a magnetic metal thin film is arranged on the abutting surfaces of both cores, the magnetic metal thin film has a saturation magnetic flux density higher than that of the magnetic core. The thickness of the core is thinned so that the width of the recording left on the magnetic recording medium at the time of recording can be defined narrowly, and at least a part of the side surface of the magnetic core excluding the magnetic core tip including the magnetic gap. A second magnetic metal thin film is disposed on the magnetic head, and the magnetic permeability of the second magnetic metal thin film is extremely high.

[0005]

As shown in FIG. 1, in the magnetic head, the magnetic metal thin film 3 is formed on the abutting surfaces of the I core and the C core.
In addition to the feature that it is a double-layered metal-in-gap magnetic head having 4 and 4, the entire magnetic core has the same thickness as the track width in order to narrow the track width TW in order to obtain high density recording. The magnetic head is made thin by processing it thinly and arranging the second magnetic metal thin films 1 and 2 or 1 or 2 on the side surface of the magnetic core including the winding window for passing the conductor for exciting the magnetic head. The thin magnetic core can be sent toward the magnetic gap without causing magnetic saturation even by the magnetomotive force generated by the excitation winding applied to excite the magnetic core. It is considered that the magnetic saturation did not occur even in the conventional magnetic head as shown in FIG. 3, but the magnetic core portion for applying the winding is 10 times larger than the magnetic core tip portion for defining the recording track. The thickness is about 20 times. The magnetic saturation does not occur because the magnetic core is thick. In addition, in order to make the vicinity of the magnetic gap thin enough to define the recording track, FIG.
It was necessary to perform the step-like processing as shown in 8 of the inside. Moreover, the processing of the step shape is an important dimensional element that determines the magnitude of the recording magnetic field generated at the time of recording, and various ideas have been made to improve the processing accuracy. On the other hand, as shown in FIG. 1, the step processing is not required in the present invention. If the magnetic permeability of the second magnetic metal thin film arranged on the side surface of the magnetic core is extremely high, the thickness of the thin film can be reduced, and the high magnetic permeability holds the magnetic flux generated by the super magnetic force of the winding conductor. In addition to the thin second magnetic metal thin film made of the high magnetic permeability material, the magnetic cores 5 and 6 are spread over the entire surface (from the leading end to the trailing end having a magnetic gap) and the width of recording left on the magnetic recording medium. Since the thickness is kept the same as the track width that regulates, the entire magnetic core is extremely thin. If the magnetic core is thinly finished, it becomes possible to keep the inductance value low even if it functions as a part of an electric circuit for recording and reproducing when a conductor for exciting is wound. When viewed as a magnetic circuit, the present invention has an effect equal to or higher than that of the conventional magnetic head, and when viewed as an electric circuit, the inductance and resistance are suppressed smaller than those of the conventional magnetic head.

[0006]

EXAMPLES The present invention will be described below with reference to examples. Figure 1
FIG. 3 is a schematic view of a magnetic head according to the present invention. 1, 2 in the figure
Is a second magnetic metal thin film which was not found in the conventional metal-in-gap magnetic head. For example, the composition formula is C
o (100-xy) Hf (x) C (y) where x =
5, 15 ≦ y ≦ 25 and the like, and it is effective that the magnetic permeability is extremely high. The film thickness of the second magnetic metal thin film depends on the magnetic permeability of the thin film. Considering the conventional head as a reference, the film thickness as shown in Table 1 is required. However, Table 1
The case where the saturation magnetic flux density of the second magnetic metal material is equivalent to that of the magnetic core (I core 6, C core 5). Saturation magnetic flux densities are about 10.5 T because materials cut from the same single crystal ferrite are used for 5 and 6. On the other hand, the Co-Hf-C thin film used in this example has a thickness of 1.5.
It has a saturation magnetic flux density of about T, and the thickness of the second magnetic metal thin film was 5 μm. Therefore, the core width is 18μ
m, a magnetic core significantly thinner than the conventional 102 μm was obtained. In FIG. 1, 3 and 4 are magnetic metal thin films arranged on the abutting surfaces of both the I and C cores to form a magnetic gap. Even with the conventional head, 3'in FIG. 3,
4'functions similarly, but due to the presence of 3 and 4, the recording magnetic field generated from the magnetic gap during recording is similarly strong at the center of the gap and has a steep rise on the I core side which is the medium outflow side. Was confirmed. Moreover, the reproducing ability was sufficient, and the recording and reproducing characteristics were equivalent to those of the conventional head. Next, when the off-track characteristics for observing the deterioration of the detection signal by displacing the track position during the detection of the recording magnetization on the recording track during reproduction were examined, the off-track characteristics according to the present invention were symmetrical. This is a characteristic that was not conventional. The possible cause is shape symmetry. In the conventional magnetic head shown in FIG. 3, as shown by 8, the step shape is processed only on one side of the side surface of the magnetic core, which is asymmetric in the track width direction. On the other hand, the present invention has a configuration symmetrical with respect to the track center as seen in FIG. Since the appearance of thin film heads in which all magnetic heads are manufactured by a thin film process in recent years, bulk type α ring heads are being replaced. However, thin film heads have the disadvantage of being too expensive to process. The first advantage is often pointed out by finishing everything with a thin film process, the path of the magnetic circuit and the electric circuit is shortened, and the inductance is suppressed to a very small value. On the other hand, it goes without saying that the conventional metal-in-gap magnetic head is inexpensive, but reduction of inductance has been a major issue. The present invention is expected to be effective in reducing the inductance because the core width can be kept small as described above.
The result of actual measurement is shown in FIG. Although the present invention could not have a smaller inductance than a thin film head,
It can be seen that the inductance can be made lower than that of the conventional metal-in-gap magnetic head.

[0007]

[Table 1]

[0008]

As described above in detail, according to the present invention, the I-shaped core and the C-shaped core are butted to each other to form the recording / reproducing magnetic gap, and the IC-shaped cores are abutted with each other. In a double-layered metal-in-gap magnetic head in which a magnetic metal thin film is arranged, the saturation magnetic flux density of the magnetic metal thin film is formed of a material higher than that of the magnetic core, and the thickness of the magnetic core is set at the time of recording. The magnetic core tip is thinly processed so that the width of the recording left on the magnetic recording medium can be defined narrowly, and the side surface of the magnetic core including a winding window for passing a conductor for exciting the magnetic head includes the magnetic gap. The core width of the magnetic head can be reduced by arranging the second magnetic metal thin film in a portion excluding the parts and using a magnetic head formed of a material having a very high magnetic permeability of the second magnetic metal thin film. It possible to, yet the recording and reproducing characteristics even though it is comparable to conventional metal-in-gap magnetic head, improved off-track characteristics (write side reading bleeding decreases), was able to reduce the inductance.

[Brief description of drawings]

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

FIG. 2 is a perspective view for clarifying the structure of FIG. 1 by partially removing the second magnetic metal thin film 2.

FIG. 3 is a perspective view showing the configuration of an example of a conventional metal-in-gap magnetic head (double-layer type), which is characterized by eight step shapes.

FIG. 4 is a diagram showing an example in which the magnetic head according to the present invention, a conventional metal-in-gap magnetic head, and a thin-film magnetic head in which all manufacturing steps are performed in a thin-film process are compared in inductance.

[Explanation of symbols]

1 magnetic metal thin film (characteristic of the present invention, arrangement of side surfaces of magnetic core) 2 magnetic metal thin film (characteristic of the present invention, arrangement of side surfaces of magnetic core) 3 magnetic metal thin film (arranged on the surface facing the I core gap) 4 Magnetic metal thin film (arranged on the surface facing the C core gap) 5 Magnetic material with track width that constitutes a C-shaped magnetic core half 6 Magnetic material with track width that constitutes an I-shaped magnetic core half 7 Magnetic Gap 8 In a conventional metal-in-gap magnetic head, a stepped shape formed by cutting off the tip of the magnetic core in order to narrow the width of the recording left on the magnetic recording medium during recording.

Claims (4)

[Claims] 1. An I-shaped core and a C-shaped core are abutted to each other to form a recording / reproducing magnetic gap of a magnetic head used for magnetic recording, and a magnetic metal thin film is arranged on the abutting surfaces of both IC cores. In the film-type metal-in-gap magnetic head, the saturation magnetic flux density of the magnetic metal thin film is made of a material higher than that of the magnetic core, and the thickness of the magnetic core is left on the magnetic recording medium during recording. The width direction is processed so that the recording width can be narrowed, and the second magnetic metal thin film is provided on at least a part of the side surface of the magnetic core except the magnetic core tip including the magnetic gap. The magnetic head is characterized in that the second magnetic metal thin film is formed of a high magnetic permeability material. 2. The magnetic head according to claim 1, wherein:
The saturation magnetic flux density of the magnetic metal thin film disposed on the gap facing surface of the I core, which is the magnetic recording medium outflow side of the first magnetic metal thin film disposed on the gap facing surface forming the magnetic gap, has the magnetic flux A magnetic head formed of a material higher than that of the magnetic metal thin film arranged on the gap facing surface of the C core. 3. The magnetic head according to claim 1, wherein:
A first magnetic metal thin film arranged on a gap facing surface forming a magnetic gap and a second magnetic metal thin film arranged on a side surface of the magnetic core.
The magnetic head is made of the same material as that of the magnetic metal thin film, and has a saturation magnetic flux density higher than that of the magnetic core and is a high magnetic permeability material. 4. The magnetic head according to claim 1,
A magnetic head in which the second magnetic metal thin film arranged on the side surface of the magnetic core is arranged on both sides or only one side of the side surface of the magnetic core.