JPS6371924A - Magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a magnetic recording medium of high output, high recording density and low noise by specifying the relative intensity ratios of the X-ray diffraction peaks of Co of a thin magnetic film which has hexagonal close- packed structure. CONSTITUTION:This magnetic recording medium is used for a video tape recorder, etc., is formed by using a thin metallic film in particle as a magnetic layer and is suitable for the high recording density. The relative intensity ratio of the X-ray diffraction peaks of the hexagonal close-packed structure of the thin magnetic film formed to such magnetic recording medium are 0.30<=(100)/(002)<2.0 and 0.15<=(101)/(002)<2.0, where (100)/(002), (101)/(002) respectively denote the relative intensity ratios of the diffracted X-ray peaks of the respective lattice planes. Said ratios are more preferably adequately so dispersed as to attain 0.30<=(100)/(002)<=1.0 and 0.15<=(101)/(002)<=1.0.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a magnetic recording medium used in a videotape recorder, etc., and particularly relates to a magnetic recording medium using a thin metal film as a magnetic layer and passing through a high recording density. It is related to recording media.

[Summary of the invention]

The present invention provides a magnetic recording medium in which a Go-PtIn thin film is formed on a substrate by vacuum evaporation, in which the relative intensity ratio of Co X-ray diffraction peaks in a hexagonally packed structure of the magnetic thin film is 0.30≦ (100) / (002) <2.0 and 0.15≦(101) / (002) <2.0
However, (100)/(002), (101)/(0
02) represents the relative intensity ratio of the diffraction X-ray peaks on each lattice plane. ] By doing so, high output and high records! The object of the present invention is to provide a magnetic recording medium that achieves low noise.

[Conventional technology]

In recent years, there has been a demand for recording short-wavelength signals such as television signals with better reproducibility, and in order to meet this demand, various magnetic recording media have been developed in an attempt to achieve high-performance recording. ing.

One of them is Tit fi 1, which is made of a thin metal film, by vacuum evaporation or evaporation. It was deposited on the substrate by a technique such as 2-talling. So-called metal thin film magnetic recording media have been proposed.

The metal F4v type magnetic recording medium is Co-Ni.
Generally, magnetic recording media have an alloy thin film as a magnetic layer, but magnetic recording media having a co-ptt gold thin film as a magnetic layer are attracting attention because of their large residual magnetic flux density and excellent corrosion resistance.

By the way, this Co-Pt alloy thin film magnetic recording medium is
This is a method of recording by magnetizing in the in-plane direction, and in order to achieve high density recording in the magnetic recording medium, it is required to have high coercive force and good squareness. In other words, this means that the axes of easy magnetization of the magnetic material used are aligned in the in-plane direction.

However, as mentioned above, in a vapor-deposited magnetic recording medium that records in the in-plane direction, if the axis of easy magnetization is perfectly aligned in the in-plane direction, the output and recording density may actually decrease during short wavelength recording. This has been elucidated based on the recording patterns of magnetic recording media and the results of simulations.

Additionally, if the easy magnetization axes are perfectly aligned in the in-plane direction, regions of magnetization in opposite directions will be adjacent to each other in adjacent magnetic materials, and a large amount of static magnetic energy will be generated at the boundary. This results in a zigzag (so-called sawtooth pattern), which is a major cause of noise generation.

[Problem that the invention seeks to solve]

In this way, in a bidirectional magnetic recording medium that records in the in-plane direction, if the axis of easy magnetization is completely in-plane, the output and recording density will decrease during short wavelength recording, or if the axis of easy magnetization is completely in-plane, There are various problems such as a large amount of static (■) energy being generated at the boundary between adjacent magnetized regions, which becomes a major cause of noise generation.

The present invention was proposed in view of the above-mentioned circumstances, and aims to suppress the generation of magnetostatic energy in a co-pt type gold metal thin film magnetic recording medium. The object is to provide a magnetic recording medium that achieves high recording density and low noise.

[Means for solving problems]

As a result of long-term intensive research to develop such a magnetic recording medium, the present inventor has found that in a vapor deposition magnetic recording medium that records in the in-plane direction, there is a magnetization reversal component in the in-plane direction and a magnetization reversal component in the direction perpendicular or oblique to the plane. We have elucidated that the magnetization reversal component from CO plays a very important role in achieving high-density recording, and we have investigated the relative X-ray diffraction peaks of CO in a hexagonally packed structure used as the magnetic thin film of the magnetic recording medium. The present invention has been completed by discovering that the above requirements can be satisfied by adjusting the strength within a certain range.

That is, the present invention provides Co -
In a magnetic recording medium formed with a P t magnetic gt film, the relative intensity ratio of the X-ray diffraction peaks of Co in the hexagonally packed structure of the magnetic thin film is 0.30≦(100)/(002)<2.0. and 0.15≦(101)/(002)<2.0.

Here, the above (100)/(002), (101)
/(002) represents the relative intensity ratio of the diffraction X-ray peaks on each lattice plane. (The same applies hereinafter) The magnetic recording medium of the present invention is one in which a gold Vrs71 film containing CO and PT as main components (80 atomic % or more) is formed on a substrate.
It has a high coercive force of 000 to 1500 (Oe) and good squareness.

This is because the CO used in magnetic recording media has a hexagonal close packing structure.
: h, c, p,), and this α-CO
This is because the C axis (axis of easy magnetization) of is oriented in the in-plane direction.

For example, a C0tsPtzs film is created by high-frequency sputtering, and the coercive force and X-ray diffraction peak intensity ratio (002)/(
100), it is found that as the coercive force increases, the C axis of α-co exists in the in-plane direction, as shown in FIG. At this time, the squareness is also improved at the same time.

However, as described above, if the C axes are aligned in the in-plane direction, problems such as a decrease in the output during short wavelength recording, a decrease in recording density, and an increase in noise due to the generation of sawtooth boundaries occur.

Therefore, the C of α-CO used as a magnetic recording medium
The axes may be appropriately distributed from the in-plane direction to the perpendicular direction to the plane. As a result of careful consideration from various angles as a method for this purpose, it was found that it is effective to bipolarize a Co--Pt magnetic thin film to form a magnetic recording medium using the vacuum bipolar method.

Here, from the results of various experiments, the relative intensity ratio of the X-ray diffraction peak of α-CO is 0.30≦(100)/(002)<2.0 and 0.15≦(101)/(002)<2. .0, preferably 0.30≦(100)/(002)≦1.0 and 0
．． It is important to disperse the particles appropriately so that 15≦(101)/(002)≦1.0.

[Function] In this way, by using α-CO with a hexagonal packing structure as a magnetic material, depositing it by vacuum evaporation, and dispersing the C-axis direction in an appropriate direction with respect to the substrate surface, short wavelength Good recording and high output.

High density recording is achieved. Furthermore, since the generation of sawtooth boundaries can also be prevented, the generation of noise is reduced.

〔Example〕

Hereinafter, specific examples of the present invention will be described, but it goes without saying that the present invention is not limited thereto.

First, a magnetic recording medium was produced using the vacuum thinning apparatus shown in FIG.

The vacuum browning apparatus consists of a vacuum chamber (1) and an exhaust system (2), and an electron gun (3) and a substrate holder (4) are installed inside the vacuum chamber (1).

CO and PT are placed in separate crucibles, heated and attached to the electron gun (3), and metal is placed on the substrate (5) on the substrate holder (4) placed opposite the electron gun (3) while simultaneously generating nuclear power. One film was formed. At that time, by using Ar gas as an inert gas, the degree of vacuum and coercive force at the time of depositing one metal thin film were adjusted. The inert gas used is limited to A gas, but N2 gas, Ne gas, Xe gas, etc. can be used.In addition, by introducing an inert gas, the orientation of the C axis of CO can be changed to the (002) plane, Each peak of the (101) plane and (100) plane can be seen.

In this example, the pt content was 15 at%, the degree of vacuum during vapor deposition was adjusted with an inert gas, and 5xto-S
, 5X10-', lXl0-Torr. These were designated as Sample I, Sample ■, and Sample ■, respectively.

The coercive force and (100
)/(002) and (101)/(002). The results are shown in Table 1.

As shown in Table 1, the Co-Pt film created by introducing an inert gas has a very large coercive force and has a peak on the (101) plane. In the case where it is not introduced, the coercive force is small and no peak of the (101) plane occurs.

Next, FIG. 3 shows the results of examining the coercive force and the relative intensity ratio of each peak when a film was formed by vacuum evaporation using Co8°Pt2°. The pt content at this time is 20 at%
, the film thickness is 800 people. Further, the inert gas used during thin deposition was Ar gas, and the coercive force was changed by changing the gas partial pressure.

As is clear from Figure 3, as the coercive force increases, <100)/(002), (101)/(00
It can be seen that the ratio 2) gradually increases, and the in-plane component of the axis increases. However, even if the coercive force increases, the peak of the (002> plane remains), which is fundamentally different from the film forming method using the sputtering method.

In a medium where the peaks of the <100) plane, (101) plane, and (002) plane occur simultaneously, the C-axis is oriented not only in the in-plane direction but also in diagonal and perpendicular directions to the plane. It is thought that there are.

Therefore, next, a rigid disk was prepared as a magnetic recording medium using a Co--Pt film, and its recording and reproducing characteristics were evaluated.

For the substrate of the above rigid disk, A+21 plated with Ni-P is used, and the film FE is 500 people, and maintenance = W.
An optical recording medium (disc A) produced according to the present invention under the conditions of 200 people each and 120 atom % of PT content.
and magnetic recording media created by conventional sputtering method (
A comparison was made with disc B).

The magnetic head used was Mn, -Zn ferrite.

The gap length is 20 μm, the rank radius is 25 mm, and the number of coil turns is 13 turns + 13 turns. The relative speed between the magnetic head and the disk is l8m/sec, and the flying height is 0.15.
Recording and reproduction were performed as μm. The results are shown in FIG. 4 and Table 2.

Table 2 These results can be used as a guideline for recording density.

When we calculated the value, it was 70 (kFRPI) for disk A, while it was 50 (kFIIPI) for disk B.
), indicating that high recording density can be achieved.

In addition, when the S/N ratio was investigated, the recording density was 30 (kFRP
In I), while it was 28 dB for disk 8, it was 25 dB for disk B.

As described above, according to the method of the present invention, compared to the conventional method, the output
It has been demonstrated that it is superior in terms of recording density, noise, etc.

M-analysis of these results revealed that those exhibiting excellent recording and reproducing characteristics during short wavelength recording had a relative intensity ratio of X-ray diffraction peaks of 0.30≦(100)/(002)<2.0 and 0. .15≦(101)/(002)<2.0 Preferably, 0.30≦(100)/(002)≦1.0 and 0.
It has been found that it is necessary that 15≦(101)/(002)≦1.0.

In this example, an example of Co-Pt film was shown, but Co-Pt film was used as an example.
Other elements 1 such as Cr, Nb, St, ACNi,
Even if elements such as Fe and Ti are added, if the amount is 20 atomic % or less, it will not affect the above results in any way.

〔Effect of the invention〕

In this way, high recording density can be achieved by using α-Co with a hexagonal packing structure as a magnetic material, depositing it by vacuum evaporation, and dispersing the C-axis direction in an appropriate direction with respect to the substrate surface. Accordingly, the influence of the in-plane magnetization component is small, and the influence of the perpendicular magnetization component is large, making it possible to perform short wavelength recording well and achieve high output and high density recording.

Further, by dispersing the easy axis of magnetization, the magnetostatic energy in the boundary region of magnetization can be reduced, so that the sawtooth boundary in the in-plane direction can be eliminated and the generation of noise can be reduced.

[Brief explanation of the drawing]

Figure 1 is a characteristic diagram showing the relationship between the coercive force and the relative intensity ratio of diffraction X-ray peaks of Co-ptFi obtained by sputtering.
The figure is a schematic diagram of a Co-Pt1j3 film forming apparatus using the vacuum evaporation method. Figure 3 is a characteristic diagram showing the relationship between the coercive force and the relative intensity ratio of the diffraction X-ray peak of the Co-Pt film produced by the vacuum evaporation method. The figure is a characteristic diagram showing the relationship between the output and recording density characteristics of a Co--Pt film by the vacuum mowaka method. Patent Applicant: Sony Corporation Representative, Patent Attorney: Kodo Koba Date: 榮- 迤 い n [OE] Figure 1 5t'h KA [Oe] Figure 3 Figure 2 Figure 4

Claims (1)

[Scope of Claims] A magnetic recording medium in which a Co--Pt magnetic thin film is formed on a substrate by a vacuum evaporation method, wherein h. c. p. The relative intensity ratio of the X-ray diffraction peak of Co is 0.30≦(100)/(002)<2.0 and 0.1
5≦(101)/(002)<2.0 [However, (100
)/(002) and (101)/(002) respectively represent the relative intensity ratio of the diffraction X-ray peaks on each lattice plane. ] A magnetic recording medium characterized by the following.