JPH0682442B2 - Magnetic recording method - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic recording method capable of obtaining a large short wavelength reproduction output.

2. Description of the Related Art Perpendicular magnetic recording has attracted attention as a magnetic recording method with excellent short wavelength recording characteristics. This system requires a magnetic layer having perpendicular magnetic anisotropy. When a signal is recorded on such a magnetic layer, the residual magnetization is oriented substantially perpendicular to the film surface. Therefore, the shorter the wavelength of the signal, the smaller the demagnetizing field in the medium and the larger the reproduction output. The perpendicular magnetic recording medium has a magnetic layer on the substrate and is made of Co-Cr, Co-V, Co-Ru or
A perpendicular magnetic anisotropic film such as Co-Cr-Rh is formed by a sputtering method or a vacuum evaporation method.

As a magnetic head for recording a signal on a perpendicular magnetic recording medium, a ring type magnetic head which has been practically used in the past or a known single magnetic pole type perpendicular magnetic head is considered.
The ring-type magnetic head has a weak perpendicular magnetic field component, which makes it difficult to record a signal on the perpendicular magnetic recording medium, whereas the single-pole perpendicular magnetic head has an optimum magnetic field for magnetizing the perpendicular magnetic recording medium. Occurs and excellent recording characteristics are obtained.

Problems to be Solved by the Invention As described above, if the single magnetic pole type perpendicular magnetic head is used,
Although recording close to ideal is performed on the perpendicular magnetic recording medium, this single magnetic pole type perpendicular magnetic head has a problem that the reproducing output is considerably small because the reproducing efficiency is generally low. Further, when a ring type magnetic head is used, the reproducing efficiency is high, but satisfactory recording on a perpendicular magnetic recording medium is difficult, so that the reproducing output is low and it is still insufficient for practical use.

Means for Solving the Problems The present invention provides a ring-shaped magnetic head in which a pair of magnetic bodies are opposed to a magnetic thin film having a larger saturation magnetization than the magnetic body via a non-magnetic layer to form a gear part, and the gear cap is provided. A thin film magnetic recording medium composed of columnar crystal grains in which a magnetic layer is inclined with respect to the substrate surface is contacted in the magnetic layer, and the relative movement direction of the ring magnetic head and the thin film magnetic recording medium The magnetic thin film of the ring type magnetic head moves so as to be on the leading edge side, and the tilt direction of the columnar crystal grains of the thin film type magnetic recording medium is recorded in a direction substantially opposite to the moving direction.

The ring-type magnetic head used in the present invention, in which a magnetic thin film having a large saturation magnetization is formed on one of the surfaces of the gear, generates a stronger magnetic field than the conventional ring-type magnetic head in the vicinity of the magnetic thin film. When a signal is recorded in the thin film magnetic recording medium in which the columnar crystal grains are inclined with respect to the perpendicular to the film surface in the region where the strong magnetic field exists, the inclination of the columnar crystal grains and the ring-shaped magnetic head of the present invention are recorded. Since the directions of the magnetic fields are close to each other, sufficient recording can be performed as compared with the conventional combination of the ring type magnetic head and the perpendicular magnetic recording medium. Furthermore, the relative movement direction of the medium and the head is set so that the magnetic thin film on the gear surface of the ring-type magnetic head is on the leading edge side,
Moreover, when the inclination of the columnar crystal grains of the medium is made substantially opposite to the moving direction of the medium with respect to the head, the recording demagnetization decreases.

Due to the above effects, the recording efficiency is improved, and as a result, the reproduction output is increased.

EXAMPLE FIG. 1 is a schematic diagram for recording a signal on a thin film magnetic recording medium in which tilted columnar crystal grains are vapor-deposited using the ring magnetic head of the present invention, and FIG. 2 is a thin film magnetic used in the present invention. 2 shows a structure diagram of a recording medium.

In the figure, (1) is a thin film type magnetic recording medium, (2) is a substrate, (3) is a magnetic layer, H is the ring type magnetic head of the present invention, (4) and (4) 'are magnetic substances, and (5) ) Is a magnetic thin film,
(6) shows a non-magnetic layer, (7) shows windings, and (10) shows columnar crystal grains.

The present invention is a ring-type magnetic head H and a magnetic recording method for recording a signal on a medium (1) in which a magnetic layer (3) has a columnar structure. The substrate (2) is made of a polymer material or the like, and a Co alloy film is excellent as the magnetic layer (3), and particularly a Co—Cr alloy film is excellent in terms of saturation magnetization, coercive force, corrosion resistance and the like. In addition, Ti, Al are formed between the substrate (2) and the magnetic layer (3).
A non-magnetic layer such as ₂ O ₃ or Ge may be provided. In the basic structure of the ring-type magnetic head of the present invention, the pair of magnetic bodies (4) and (4) 'constituting the head core have a non-magnetic layer as a gear member, as in a general ring-type magnetic head. (6) is sandwiched between them so that they face each other. However, the ring type magnetic head H used in the present invention has a magnetic field having a larger saturation magnetization between the magnetic body (4) 'and the non-magnetic layer (6) than the magnetic body (4) and the magnetic body (4)'. A thin film (5) is formed. Recording is performed by passing a signal current through the winding (7).

The arrow (8) in FIG. 1 indicates the relative movement direction of the thin film magnetic recording medium (1) with respect to the ring type magnetic head H. In the ring-shaped magnetic head H , the vicinity of the head core gear on the side where the thin-film magnetic recording medium (1) enters is called a leading edge, and the opposite side is called a trailing edge. As shown in FIG. 1, when the ring type magnetic head H and the thin film magnetic recording medium (1) move relative to each other in the direction of the arrow (8), the magnetic thin film (5) is located on the leading edge side. When the relative movement direction is opposite to the arrow (8), the magnetic thin film (5) is on the trailing edge side. The columnar crystal grains of the magnetic layer (3) in the thin film magnetic recording medium (1) are inclined by an average θ with respect to the perpendicular (9) of the recording film surface. When the inclination of the columnar crystal grains is opposite to the moving direction of the thin film magnetic recording medium, 0 ° <
Means θ <90 °.

FIG. 2 is an enlarged schematic view of the vicinity of the magnetic layer (3) in FIG.

(10) is a columnar crystal grain, and when the film thickness of the magnetic layer (3) is about 2000Å, the grain size is about 200 to 500Å. Also,
When the well-known continuous vapor deposition method, that is, the vacuum vapor deposition method in which a thin substrate is continuously formed while running a long substrate, the incident angle of vaporized atoms to the substrate (2) is continuously changed. Therefore, the curvature of the columnar crystal grains as shown in FIG. 2 can be seen.

Next, actual recording / reproducing characteristics recorded on the thin film magnetic recording medium of the present invention by using the ring type magnetic head of the present invention will be described.

A polyimide film with a film thickness of 10 μm is used as the substrate (2), and a Ti film with a film pressure of 200 Å is formed on the polyimide film by continuous vapor deposition
On top of this, a film thickness of 2000Å of 80Co-
The thin-film magnetic recording medium (1) on which the 20Cr film is formed is
Recording and reproduction were performed using the ring type magnetic head used in the present invention and the conventional ring type magnetic head having the structure shown in the figure. The above-mentioned Ti film has 80Co-20Cr on it.
It is used to increase the coercive force of the film. Also, 80Co
The saturation magnetization of the --Cr film is 400 emu / cc, the average inclination angle θ of the columnar crystal grains (10) is 30 °, and the coercive force in the direction in which the columnar crystal grains are inclined in the film plane is 800 e. A conventional ring-type magnetic head made of Mn-Zn ferrite with a gear length of 0.14 μm was used. As the ring type magnetic head H having the structure shown in FIG. 1, the magnetic body (4) and the magnetic body (4) 'are the same Mn-Zn ferrite as in the conventional case, and the magnetic thin film (5) is a Co-layer having a thickness of 3 .mu.m. Amorphous Nb-Zr was used, SiO was used for the non-magnetic layer (6), and the thickness of the non-magnetic layer (6), that is, the gap length was 0.14 μm. Both magnetic heads have a gear width of 30 μm and a gear depth of 10 μ.
m, the number of coil turns is 16 turns. The following table shows the reproduction output when recording and reproducing with these magnetic heads.

The signal recording density is 150KFRPI. Here, 150 KFRPI is a recording state of a digital signal having magnetization reversal 150,000 times per inch. Columnar crystal grains (10) of magnetic layer (3)
Is inclined in the direction indicated by θ in FIG. 1, that is, in the direction of 0 ° <θ. Further, using a conventional ring-type magnetic head, the reproduction output value when recording / reproducing is performed by setting the moving direction of the medium with respect to the head in the direction of arrow (8) in FIG.
It is set to 0 dB. Further, in the same table, the reproduction output when recording / reproducing on the perpendicular magnetic recording medium made of the 80Co-20Cr alloy thin film having a film thickness of 2000Å with the above-mentioned conventional magnetic head is also described. The coercive force of the 80Co-20Cr alloy thin film in the direction perpendicular to the film surface is 800e.

From the table, in the ring-type magnetic head of the present invention having the structure shown in FIG. 1, the film-type magnetic head in which the magnetic layer has a columnar structure and the crystal grains are inclined with respect to the perpendicular of the film surface. When the relative movement direction is set to the direction of the arrow (8) in FIG. 1 and the inclination direction of the columnar crystal grains is set to the direction opposite to the movement direction of the medium for recording and reproducing, the conventional ring type magnetic head is used. It can be seen that a reproduction output that is 7 dB higher than that obtained when recording / reproducing in the relative movement direction of the arrow (8) in FIG. 1 is obtained. When the relative movement direction is the opposite direction of the arrow (8) in Fig. 1, the output is 3 dB more than the direction of the arrow (8).
Low. Further, compared with the case where recording / reproduction is performed on the perpendicular magnetic recording medium by the conventional ring type magnetic head, the reproduction output of the present invention is 10 dB higher.

In addition, the tilt direction of the columnar crystal grains of the magnetic layer (3) is made opposite to the direction shown by θ in FIG. 1, and the ring-shaped structure having the structure shown in FIG. When recording / reproducing is performed using a magnetic head, the arrow (8) in FIG.
The relative output when the thin film magnetic recording medium is moved in the direction of −5 dB, and the relative output when the thin film magnetic recording medium is moved in the direction opposite to the arrow (8) in FIG. 1 is −2 dB, High playback output cannot be obtained.

The above experimental results can be interpreted as follows.

In contrast to the conventional ring type magnetic head, the ring type magnetic head of the present invention as shown in FIG. 1 has a magnetic thin film (5).
A strong magnetic field is generated in the vicinity of, and the inclination of the magnetic field strength in the medium running direction becomes steep, so that the recording characteristics are excellent. When a signal is recorded on a thin film magnetic recording medium in which the columnar crystal grains are inclined with respect to the perpendicular to the film surface in a region having this strong magnetic field, the inclination of the columnar crystal grains and the direction of the head magnetic field are close to each other. Recording is more possible than the combination of the ring type magnetic head and the perpendicular magnetic recording medium. Further, if the direction of relative movement of the thin-film magnetic recording medium with respect to the head is set to the direction of arrow (8) in FIG. 1, the recording demagnetization is less than in the opposite case, and it is considered that a large residual magnetization remains in the magnetic layer. .

The reproduction output in the above table is expressed as a relative value.
In the ring type magnetic head of the present invention having the structure shown in the figure, the absolute value of the reproduction output is 450 μv / turn · mm · m / sec when the relative movement direction is the direction of arrow (8) in FIG. . This value far exceeds the reproduction output of the perpendicular magnetic recording medium which has been conventionally reported. Note that 450 μv /
The turn / mm / m / sec means that the number of turns of the coil is 1 turn, the gap width is 1 mm, and the head output is 450 μv per 1 m / sec of the relative velocity between the medium and the head.

The present invention provides the thin film magnetic recording medium of the present invention by the ring magnetic head of the present invention with the magnetic thin film provided on one side of the gear part on the leading edge side, and the columnar crystal grains of the thin film magnetic recording medium. A large short-wavelength reproduction output can be obtained by recording with the tilt direction of the recording medium set to the direction opposite to the moving direction of the thin film magnetic recording medium.

[Brief description of drawings]

FIG. 1 is a schematic view of recording a signal on a thin film magnetic recording medium in which tilted columnar crystal grains are vapor-deposited using the ring magnetic head of the present invention, and FIG. 2 is a structure of the thin film magnetic recording medium of the present invention. Fig. 1: thin film type magnetic recording medium, 2: substrate, 3: magnetic layer in which columnar crystal grains are inclined with respect to the perpendicular of the film surface, 4, 4 ': magnetic substance forming a head core, 5: more than magnetic substance Magnetic thin film with large saturation magnetization, 6: non-magnetic layer, 7: winding, 8: arrow indicating the traveling direction of the thin film magnetic recording medium with respect to the ring type magnetic head, 9: perpendicular to the film surface, 10: columnar crystal grains

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Taro Nanbu 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 57-40722 (JP, A) JP 59-201211 (JP, A)

Claims (1)

[Claims] 1. A ring-type magnetic head, in which a pair of magnetic bodies are opposed to a magnetic thin film having a larger saturation magnetization than the magnetic bodies via a non-magnetic layer to form a gap portion, and the magnetic layer is provided in the gap portion on a substrate surface. A thin film magnetic recording medium composed of columnar crystal grains tilting with respect to each other is contacted in its magnetic layer, and the relative movement direction of the ring type magnetic head and the thin film type magnetic recording medium is determined by the magnetic thin film of the ring type magnetic head. Is moved to the reading edge side and the tilting direction of the columnar crystal grains of the thin film magnetic recording medium is set to a direction substantially opposite to the moving direction for recording.