JPS6059515A - Magnetic head - Google Patents

Abstract

PURPOSE:To improve the recording and reproducing efficiency of a head by forming an exciting coil for efficient recording newly on the head having a structure winding a thin film coil around a main magnetic pole. CONSTITUTION:Two coils 10, 11 are wound around the main magnetic pole 4. The coil 11 is wound around the leading end part of the main magnetic pole 4, and at the writing time, current is made to flow between drawing electrodes 14, 15 to supply current to the coils and generate a magnetic field. At the reading time, the change of magnetic flux passing the inside of the coil 10 is detected by detecting voltage induced between the electrodes 13, 14. The coil 11 is expanded at its coil width so that much current is made to flow into the coil 11 to be used as a write-only coil and the coil 10 is narrowed at its coil width and increased at the number of times of winding so that current flow is interrupted to be used as a read-only coil. Consequently, the output can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head having a structure suitable for perpendicular magnetic recording.

An object of the present invention is to obtain a magnetic head (hereinafter referred to as a perpendicular head) for use in perpendicular magnetic recording that is excellent in both recording efficiency and reproduction efficiency and is practical.

As a perpendicular head, the main pole auxiliary pole type perpendicular head shown in Figure 1 has been proposed since the beginning of research and has shown excellent head characteristics, and it is believed that the above head is the best in terms of performance for perpendicular magnetic recording. is Daikichi's evaluation. This type of head has a main magnetic pole made of a high magnetic permeability thin film 4,
The structure is such that auxiliary magnetic poles consisting of a ferrite 5 and a coil 6 wound around the ferrite 5 are arranged on both sides of the media. This type of head is not practical because it is made up of two blocks, which increases the cost, and there is also the problem of complicated adjustment when mounting the drive.

Therefore, a head having a structure in which a coil 7 is wound around a main pole 4 is currently being proposed (FIG. 2). coil 7
There are two types of coils: coils made of conductive wire (hereinafter referred to as bulk coils), and coils formed from conductive thin films (hereinafter referred to as bulk coils).
There are two possible types: thin film coil. A head having a structure in which a thin film coil is wound around the main pole is considered to be superior in the following two points. First of all, the shape processing of the head is simple. In other words, when using bulk coils, grooves or holes are required for arranging the coils, and as a result, the shape of one head becomes complicated. Furthermore, in order to arrange the coil at the tip of the head, high accuracy in shape processing is required, and a high level of processing technology is also required. Second, thin film coils are compact and can be wound around the very tip of the main pole.
No. 6, the regeneration efficiency is higher than when using a bulk coil.
FIG. 4 shows the results of writing and reading using a vertical head using a thin film coil having the structure shown in the figure. In this case, an auxiliary magnetic pole was placed on the opposite side of the medium in addition to the head shown in FIG. 3, and was used at appropriate times during writing and reading. The thin film coil used has a coil pitch of 10μ.
This is a 9-turn game. FIG. 4 shows the relationship between recording current and reproduction output in 5K FRP construction. The dotted line A shows the results when the write head is the auxiliary magnetic pole and the read head is the thin film coil 8. The solid line is the result of a standard combination in which the write head is an auxiliary magnetic pole and the read head is also an auxiliary magnetic pole. The dot-dashed line C indicates that the write head is a thin film coil 8.
These are the results when the reproducing head is an auxiliary magnetic pole. It is clear from FIG. 4 that although the thin film coil has extremely high reproduction efficiency, the thin film coil shown in FIG. 3 has poor writing characteristics. A possible reason for this is that the main pole around which the thin film coil is wound easily becomes magnetically saturated, making it impossible to guide the magnetic flux generated by the coil to the tip of the main pole. be. As a result, saturation recording cannot be performed. To prevent this, it is necessary to increase the distance between the coil and the main magnetic pole. In the case of a thin-film coil, this corresponds to increasing the thickness of the electrical insulation film between the main pole and the coil.

However, increasing the film thickness is not an appropriate solution because it makes it difficult to maintain pattern accuracy by etching the film.

The present invention relates to a head having a structure in which a thin film coil is wound around the above-mentioned main pole.In order to perform efficient recording, an excitation coil is newly provided, and the recording characteristics of the head are improved. be.

FIG. 5 shows one embodiment of the present invention. Two coils, a coil 10 and a coil 11, are wound around the main magnetic pole 4. The coil 11 is wound around the tip of the main magnetic pole, and during writing, a current is passed between the extraction electrodes 14 and 15 to energize the coil 11 and generate a magnetic field. At the time of reading, changes in the magnetic flux passing inside the coil 10 are known by detecting the voltage induced between the extraction electrodes 13 and 14. Since the coil 11 is used only for writing, the width of the coil is wide so that a large amount of current can flow therethrough. In this example, the coil 11 has one turn, but increasing the number of coil turns does not necessarily increase the magnetic flux density at the tip of the main pole. On the other hand, since the coil 10 is read-only, no current flows through it, so it is possible to narrow the coil width, reduce the coil pitch, and increase the number of coil turns.
Furthermore, the output can be improved.

Figure 6 shows an example of the characteristics of the magnetic head of the present invention (5)
.

vinegar. FIG. 6 shows the relationship between recording current and reproduction output in 5K FRP construction. The dotted line σ is the result when the write head is the auxiliary magnetic pole and the read head is the thin film coil 10. The solid line represents the results when the write head is the thin film coil 11 and the read head is the thin film coil 10, and shows the ability of the head of the present invention. The dashed line C shows the result when the write head is the thin film coil 10 and the read head is also the thin film coil 10, which corresponds to the conventional example. As is clear from FIG. 6, the reproduction output when writing is performed using the coil 11 of the magnetic head of the present invention is improved to the same level as the reproduction output when writing is performed using the auxiliary magnetic pole. ing. It can be said that a sufficiently strong magnetic flux is emitted from the tip of the main magnetic pole 4.

As described above, the magnetic head according to the present invention enables good recording on the same level as a main pole auxiliary pole type vertical head.
The reproduction output per turn of the coil was also greater than that of the main magnetic pole auxiliary magnetic pole type vertical head. The head shape and structure are simple, and the practicality of the head of the present invention is high.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a main pole auxiliary pole type vertical head. FIG. 2 is a schematic diagram of a vertical head of the type in which a coil is wound around the main pole. FIG. 3 shows a vertical head with a thin film coil wound around the main pole. FIG. 4 is a graph showing the relationship between the recording current and the normalized relative output of the vertical head having the structure shown in FIG. 3. FIG. 5 is an example of the magnetic head of the present invention. 3 is a graph showing the relationship between the recording current and the normalized relative output of the magnetic head of FIG. 1... Media substrate 2... High magnetic permeability film 6,... Perpendicular magnetization film 4... Main magnetic pole (high magnetic permeability thin film) 5... ...
Ferrite 6... Coil 7... Coil lt film coil aluminum or bulk coil) 8... Thin film coil 9... Substrate (becomes head slider) 10・
... Thin film coil 11... Thin film coil 12... Substrate (becomes head slider) 13.14
, 15... Lead-out electrode device Applicant: Suwa Seikosha Co., Ltd. Agent, Patent Attorney Mogami Muto 辣wo 9 Figure 4'' /4 /r /'' To Biba Denko Figure 6, Figure 5

Claims (1)

[Claims] In a magnetic head comprising a main pole made of a patterned soft magnetic thin film, and a plurality of thin film coils made of an electrically conductive thin film wound around the main pole, the plurality of thin film coils are an excitation coil for writing and a readout coil. 1. A magnetic head, wherein the excitation coil for writing is arranged at the tip of the main pole.