JPS6025027A - Magnetic disk - Google Patents

Abstract

PURPOSE:To reduce the percentage of a vertical magnetization recording component mixed with a horizontal magnetization recording component and to enable high- density recording by forming a Co-Cr film on a substrate as a vertical magnetization recording medium and a gamma-Fe2O3 film of a specified thickness on the Co-Cr film as a horizontal magnetization recording medium. CONSTITUTION:A vertical magnetization recording medium and a horizontal magnetization recording medium of 0.01-0.3mum thickness are successively formed on a nonmagnetic substrate. The vertical magnetization recording medium is a Co-Cr film with vertical anisotropy formed by sputtering, and the horizontal magnetizaton recording medium is a gamma-Fe2O3 film formed continuously on the Co-Cr film by sputtering. Both of the recording media are magnetically reversed, and the reversed horizontal magnetization recording component is used in the recording and reproduction of information. The vertical magnetization recording component is considerably reduced as compared to a vertical magnetization recording medium of Co-Cr having a single-layered structure, and when the thickness of the horizontal magnetization recording medium is >=0.01mum, the vertical magnetization recording component is scarcely contained in reproduced wave-form, so any complex signal processing technique is not required during reproduction.

Description

[Detailed description of the invention] (a) Technical field of the invention The present invention relates to improvements in magnetic disks.

(bl) Prior Art and Problems A magnetic head is installed at a predetermined distance from the magnetic disk on a magnetic disk in which a magnetic recording medium made of a magnetic film is formed on a non-magnetic substrate made of, for example, aluminum (AI). However, a magnetic disk device that records and reproduces information on a magnetic recording medium using the magnetic head is well known.

Recently, as a magnetic recording medium used for such magnetic disks,
In order to improve magnetic recording density, cobalt-chromium (C
A perpendicular magnetization recording medium having magnetic anisotropy in the direction perpendicular to the film surface, such as an o(:r) film, has been proposed. .

Furthermore, in order to improve magnetic recording sensitivity, a two-layer perpendicular magnetization recording medium has been developed in which a high permeability nickel-iron (NiFe) film is formed on a substrate, and then the CoCr film is formed on the NiFe film. .

Many magnetic heads for recording and reproducing information on magnetic recording media have also been proposed, but at present, as shown in FIG. 1, a ring-shaped magnetic head 2 is mounted on a CoCr film 1 formed on a substrate. It has become possible to experimentally achieve high-density recording of 1xlOBPI (1-7 inch pitch) when installed at predetermined intervals, so it is possible to form perpendicular magnetization recording media of this Co(:r film). A magnetic disk device that combines a magnetic disk and a ring-shaped magnetic groove is promising for high-density recording.

However, when trying to record and reproduce information using such a ring-shaped magnetic head 2, the leakage magnetic flux 3 from the magnetic head 2 has a semicircular arc shape, so even if a perpendicular magnetization recording medium is formed on the substrate. Even if this happens, the reproduced output of the recorded information will be as shown in Figure 2, where A and B are not equal, and a vertical magnetization component will be mixed in addition to the horizontal magnetization component, causing problems in the modulation and demodulation of the recorded signal. This poses problems such as the need for complex signal processing techniques. In the above matter, when B/A=1, there is only a vertical magnetization component, and when B/A=0, there is only a horizontal magnetization component. The horizontal axis in FIG. 2 indicates the time (μ5e
C), and the vertical axis shows the playback output.

OBJECT OF THE INVENTION The present invention eliminates the above-mentioned problems, and after recording information on a magnetic recording medium on a magnetic disk using the ring-shaped magnetic head, when reproducing the recorded information, the horizontal magnetization is Reduce the proportion of perpendicular magnetization recording components mixed in the recording components,
Another object of the present invention is to provide a new magnetic disk capable of high-density recording.

(d) Structure of the invention The magnetic disk of the present invention for achieving the above object comprises:
A perpendicular magnetization recording medium is formed on a nonmagnetic substrate, and a horizontal magnetization recording medium having a film thickness of 0.01 μm to 0.3 μm is formed on the perpendicular magnetization recording medium. Further, the perpendicular magnetization recording medium is a CoCr film having perpendicular anisotropy formed by a sputtering method, and the horizontal magnetization recording medium is γFe20 a B* formed continuously on a CoCr film by a sputtering method. That is.

Further, the magnetization of both the horizontal magnetization recording medium and the perpendicular magnetization recording medium of the magnetic disk is reversed, and the horizontal magnetization recording component with the magnetization reversed is used for recording and reproducing information.

(e) Embodiment of the Invention An embodiment of the invention will be described below in detail with reference to the drawings.

FIG. 3 is a cross-sectional view of the magnetic disk of the present invention, FIG. 4 is a schematic diagram showing a state in which a ring-shaped magnetic head is installed on the magnetic disk of the present invention for recording/reproduction, and FIG. 5 uses the magnetic disk of the present invention and has a gap length of 0.8μ.
Figure 6 shows the reproduced waveforms when recording/reproducing is performed using a magnetic head of 0.2 μm in length using the magnetic disk of the present invention. The reproduction waveform of FIG. 7 is the magnetic disk of the present invention,
Alternatively, it is a diagram comparing and examining the ratio of the vertical magnetization recording component and the horizontal magnetization recording component when reproducing information recorded using a conventional magnetic disk.

As shown in FIG. 3, the magnetic disk of the present invention includes a perpendicular magnetization recording medium 12 made of a CoCr film with a thickness of 1 μm formed on a non-magnetic substrate 11 such as aluminum or glass by a sputtering method. A horizontal magnetization recording medium made of a 0.1 μm γFe203 film 13 is formed on the perpendicular magnetization recording medium.

The Go(:rl!ii) has perpendicular magnetic anisotropy, and the coercive force in the direction perpendicular to the film surface is 700 oersteds, and the coercive force in the horizontal direction to the film surface of γFe203 is 7
00 Oersted.

To form such a magnetic disk, an aluminum or glass substrate is introduced into a container of a sputtering device, the inside of the container is evacuated to a degree of vacuum of ixio-6, and then argon (^r) is injected into the container. ) A gas is introduced as a spuckling gas, and a CoCr film 12 with a thickness of 1 μm is formed on the substrate 11 using a CoCr target. Next, the target is replaced with a target containing iron (Fe) as the main component and Go, titanium (Ti), and copper (Cu) added thereto, and an αPe203 film is sputtered onto the Go(:r film 12 of the substrate 11). After forming γFe2, the substrate is heat-treated to form γFe2.
A horizontal magnetization recording medium made of the 03 film 13 is formed. As shown in FIG. 4, ring-shaped magnetic heads 21 made of ferrite are placed on the thus formed magnetic disk at predetermined intervals, and the gap length l of the magnetic heads 21 is set to 0. FIG. 5 shows the reproduction output when the flying height is 8 μm (flying height 0.27 μm).

In FIG. 5, the vertical axis represents the reproduction output, and the horizontal axis represents the time it takes for the magnetic head to pass through the isolated magnetization reversal region.

As shown in the reproduction curve 31 in the figure, the perpendicular magnetization recording component explained in FIG. I can see that it is. Furthermore, when information is reproduced by the magnetic disk of the present invention using such a magnetic head, the reproduction output is higher than that of a conventional magnetic disk in which only a horizontally magnetized recording medium is formed on a single layer structure on a substrate. An increase of 50% was also confirmed through experiments.

On the other hand, FIG. 6 shows a reproduced waveform when the gap length l of the ring-shaped magnetic head 21 shown in FIG. 4 is set to 0.2 μm (levitation itO, 07 μm). As shown in the reproduction curve 32 in the figure, the perpendicular magnetization recording component explained in FIG.
'(B/A)=03.

Next, FIG. 7 shows a ring-shaped magnetic head 2 installed on the magnetic disk with respect to a conventional magnetic disk in which only a perpendicular magnetic recording medium is formed in one layer and a magnetic disk of the present invention.
The ratio of Gui pulses when changing the gap length a of 1 (B
/A) is shown. In the figure, the horizontal axis shows the gap length Il (μm), and the vertical axis shows B/A. When the magnetic disk of the present invention is used, the perpendicular magnetization recording becomes as shown in curve 41, compared to curve 42 when a conventional Co-Cr perpendicular magnetization recording medium is formed on a substrate with a single layer structure. ingredients are significantly reduced. If the thickness of the horizontal magnetization recording medium made of the γFe203 film formed on the perpendicular magnetization recording medium of the CoCr film is 0.01 μm or more, the reproduced waveform will hardly contain the perpendicular magnetization recording component, and when reproducing the recorded information. Eliminates the need for complex signal processing technology. The upper limit of the thickness of the horizontal magnetization recording medium varies depending on the magnetic gap length or the flying height, but various experiments have shown that 0.3 μm is sufficient. Furthermore, when trying to increase the density of recorded information on a magnetic disk in which only a horizontally magnetized recording medium is formed on a substrate, the film thickness of the recording medium must be made thin, which has the disadvantage of reducing the reproduction output. According to the magnetic disk of the present invention, the advantages of high-density recording and improved reproduction output are obtained.

([1. Effects of the Invention As described above, according to the magnetic disk of the present invention, in the process of reproducing recorded information, the vertical magnetization recording component and the horizontal magnetization recording component are not mixed, so complex signal processing is not necessary. Moreover, it is possible to obtain a magnetic disk that improves the reproduction output without reducing the recording density.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the recording/reproducing state when using a conventional magnetic disk, Figure 2 is a diagram showing the reproduction output when using a conventional magnetic disk, and Figure 3 is a diagram showing the magnetic disk of the present invention. FIG. 4 is a schematic diagram of the state in which a ring-shaped magnetic head is installed on the magnetic disk of the present invention for recording/reproducing, and FIGS. 5 and 6 are details of the present invention. FIG. 7 is a diagram for comparing the Goi pulse ratio between the magnetic disk of the present invention and a conventional magnetic disk. In the figure, 1 and 12 are CoCr films, 2 and 21 are ring-shaped magnetic heads, 3 is leakage magnetic flux, 11 is a substrate, and 13 is γF
e2O8 film, 31 is the reproduction waveform when using a magnetic head with a gap length of 0.2 μm, 32 is the gap length of 0.8 μm
41 is a reproduction waveform when a magnetic head of the present invention is used, 42 is a reproduction waveform when a conventional magnetic disk is used, and 1 is a gap length. Figure 1! Figure 82 Figure 93 VJ Building Figure 4 Figure S Figure 6 Figure 71i → Gil Rough ° Length QJm)

Claims (3)

[Claims] (1) A perpendicular magnetization recording medium is formed on a non-magnetic substrate, and a film thickness of 0.018 m "0.3" is formed on the perpendicular magnetization recording medium.
A magnetic disk characterized in that a horizontal magnetic recording medium of μm is formed. (2) The perpendicular magnetization recording medium is a CoCr film having perpendicular magnetic anisotropy formed by a spunter method, and the horizontal magnetization recording medium is a γ film formed on a CoCr film by a spunter method.
The magnetic disk according to claim 1, characterized in that it is a Fe203 film. (3) A patent claim characterized in that the magnetization of both the horizontal magnetization recording medium and the perpendicular magnetization recording medium of the magnetic disk is reversed, and the horizontal magnetization recording component with the magnetization reversed is used for recording and reproducing information. The +1st term in the range, or the (2nd) term in the range
) The magnetic disk described in section 2.