JPH02108207A - Magnetic head - Google Patents

Abstract

PURPOSE:To narrow the interval of a gap and to attain the high density recording the providing a metallic magnetic film with a large saturated magnetic flux density on the surface of the head core opposite to a recording medium. CONSTITUTION:A metallic magnetic film 8 composed of Fe-Al-Si is provided on the surface of a magnetic head 1 opposite to a magnetic disk 2. Thus, by providing the metallic magnetic film 8 with a large saturated magnetic flux density, the magnetic flux density to pass through a gap 4 in the same way as an MIG head can be increased, and thus, in a recording medium 5 of the magnetic disk 2, the magnetic flux density necessary for the recording and reproducing of the information can be secured. The metallic magnetic film 8 can be formed by the sputtering method, etc., the magnetic film 8 is brought into contact with the head core 3 composed of ferrite, since it is extended in the surface direction, it does not work as a gap, for this reason, the generation of the pseudo peak can be prevented, and since the tip of the gap is composed of the metallic magnetic body with the large saturated magnetic flux density, the interval (gap length) of the gap can be narrowed and thus, the high density recording can be executed.

Description

[Detailed Description of the Invention] [Summary] Regarding a magnetic head that records and reproduces signals on a recording medium of a magnetic disk, for the purpose of improving the recording density, a magnetic head with a high saturation magnetic flux density is provided on the surface of the head core facing the recording medium. A magnetic head is constructed by providing a metal magnetic film.

[Industrial application field]

The present invention relates to a magnetic head that enables high-density recording.

A magnetic disk is a disk made of a non-magnetic metal such as an aluminum (AI) alloy, and a magnetic recording medium is placed on a disk using a spin code method.
The magnetic film is formed by reducing the thickness to less than 111 m using methods such as vacuum evaporation and sputtering.

That is, the recording medium is T-ferrai)(r-Pe20
) and barium ferrite (BaO・6Pez03)
The spin code method is used for oxides such as cobalt chromium (Co-
For those using magnetic alloy films such as Cr) or nickel-cobalt-phosphorus (Ni-Co-P), vacuum evaporation and sputtering methods are used.

A magnetic disk drive rotates a magnetic disk at high speed, and uses the resulting lifting force to levitate a slider with a built-in magnetic head across a small gap.A high-frequency signal current is passed through the coil of the magnetic head, and the magnetic field lines generated from the coil cause the slider to float. Recording is performed by magnetizing the recording medium of a magnetic disc, and the magnetic field lines from the magnetized recording medium are received by the coil of the magnetic head and converted into electric signals to reproduce the recorded data.

[Conventional technology]

As a method of improving the recording density of a magnetic disk, narrowing the gear 7 of the magnetic head has been carried out.

FIG. 2 shows the structure of an MIG (abbreviation for M6tal in gap) head, and the structure of the magnetic head will be explained using this.

The magnetic head 1 floats above the magnetic disk 2 with a minute interval of about 0.2 μm maintained, and the recording medium 5 of the magnetic disk 2 is magnetized by lines of magnetic force from the gap 4 provided in the head core 3 made of ferrite. Information is being recorded.

The magnetic head 1 has a coil 6 wound around a bed core 3, and as the gap (commonly known as gap length) 4 of the core provided at a position facing the magnetic disk 2 narrows, the distribution of magnetic lines of force changes. Recording medium 5 to become narrower
Since the area required for one bit is small, recording density can be improved by narrowing the gap 4.

Here, since information is recorded on the recording medium 5 of the magnetic disk 2 by the horizontal component of the lines of magnetic force passing through the gap 4, as the gap 4 is narrowed, the signal current of the coil 6 is increased and the magnetic flux density is increased. There is a need.

However, the saturation magnetic flux density (Bs) of the ferrite constituting the head core 3 is about 5000G (Gauss) at maximum, and even if the signal current of the coil 6 is increased, it will reach saturation and will not contribute to an increase in the magnetic flux density. .

Therefore, as the gap 4 becomes narrower, the magnetic flux density to the recording medium of the magnetic disk 2 decreases, and the override characteristic deteriorates.

As a countermeasure against this problem, an MIG head has been put into practical use in which a metal magnetic film 7 having a high saturation magnetic flux density is provided on one or both sides of the gap 4, as shown in FIG.

By using RAD for this MIG, the magnetic flux density increases, making it possible to obtain sufficient override characteristics even with a narrow gear knob.

However, there is a problem in that the boundary between the metal magnetic film 7 and the herad core 3 acts as a gap, causing pseudo peaks as shown in FIG. 3(B) during reproduction, and it is easy for the detector to mistake these pseudo peaks as signals. occurred, and a solution was needed.

[Problem to be solved by the invention]

As described above, in order to increase the recording density of a magnetic disk, it is necessary to narrow the gap of the magnetic head, and the MIG bed is used as a method to prevent the decrease in magnetic flux density to the magnetic disk.

However, the problem is that the interface between the metal magnetic film that makes up the MIG bed and the herad core acts as a gap (therefore, pseudo peaks are generated, impairing reliability), and solving this problem is a challenge. be.

[Means to solve the problem]

The above problem can be solved by constructing a magnetic head by providing a metal magnetic film with a high saturation magnetic flux density on the surface of the head core facing the recording medium of the magnetic disk.

[Effect]

In the present invention, a metal magnetic film 8 is provided on the surface of the magnetic head 1 facing the magnetic disk 2, as shown in FIG.

By providing the metal magnetic film 8 with a high saturation magnetic flux density in this way, it is possible to increase the magnetic flux density passing through the gap 4 similarly to the MIG head, which is necessary for recording and reproducing information on the recording medium 5 of the magnetic disk 2. It is possible to ensure a high magnetic flux density.

Here, the metal magnetic film 8 can be formed by sputtering or the like, but with such a structure, the interface between the metal magnetic film 8 and the helad core 3 seems to act as a gap, similar to the case of the MIG head. However, since the metal magnetic film 8 deposited by a physical method such as sputtering is in close contact with the head core 3 made of ferrite and extends in the plane direction, it does not function as a gap.

FIG. 3(A) shows the reproduced output waveform of the magnetic head formed in this way, and it can be seen that no pseudo peaks occur compared to the MIG head of FIG. 3(B).

〔Example〕

In the embodiment of the present invention shown in FIG. 1, the metal magnetic film is made of iron, aluminum, silicon (Fe-8β-5i).
Sendust alloy consisting of was used.

The saturation magnetic flux density of this alloy is approximately 10,000G.

This alloy was formed to a thickness of 2 μm on one side of the head core using a sputtering method.

Figure 3 (A) shows the reproduced output waveform of the magnetic head, and the measurement conditions were as shown in the figure: the circumferential speed was 12.5 m.
/s, and the writing frequency is 1 MHz.

As can be seen from this figure, there is no generation of pseudo peaks, which is a problem with MIG heads, and high frequency writing is also possible.

〔Effect of the invention〕

By implementing the present invention, it is possible to prevent the occurrence of pseudo peaks, and since the tip of the cap is made of a magnetic metal material with a high saturation magnetic flux density, the gap interval (gap length) can be narrowed, which enables high-density recording. It becomes possible.

[Brief explanation of drawings]

FIG. 1 is a schematic front view of a magnetic head according to the present invention, FIG. 2 is a schematic front view of an MIG head, and FIGS. 3A and 3B are reproduction output waveform diagrams, respectively. In the figure, 1 is a magnetic head, 2 is a magnetic disk, 3 is a helad core, and 5 is a recording medium. 4 is a gear, 2 is a metal magnetic film, and 7.8 is a metal magnetic film.
] No. 1 ■ Reed 3

Claims (1)

[Claims] Floating from the surface of a magnetic disk rotating at high speed due to lift force,
A magnetic head that records and reproduces signals on a magnetic disk recording medium is characterized by a metal magnetic film (8) with a high saturation magnetic flux density provided on the surface of the head core (3) facing the recording medium (5). magnetic head.