JPS5922236A - Production of vertical magnetic recording medium - Google Patents

Abstract

PURPOSE:To form ''Parmalloy'' and Co-Cr films with superior orientation, by forming these films by a vacuum method so that the ratio of the average extracting speed of a Ti film to the oxygen partial pressure in a vacuum vapor deposition device exceeds a specific value. CONSTITUTION:It is necessary to reduce the half-amplitude level DELTAtheta50' of a rocking curve on the (111) surface of the ''Parmalloy'' film in order to reduce the DELTAtheta50 half-amplitude level of a rocking curve on the (002) surface of the Co- Cr film, i.e. it is necessary to reduce the DELTAtheta50, to <=26 deg. in order to reduce the DELTAtheta50 to <=18 deg.. Namely, it is necessary to reduce the DELTAtheta50' of the ''Parmalloy'' film to <=26 deg. to obtain a two-layer film medium provided with superior recording and reproducing characteristics. When the ''Parmalloy'' film is formed on the Ti film evaporated under the condition that the ratio (x) of the average extracting speed of the film to the oxygen partial pressure in the vacuum vapor deposition device is >=1.5X10<6>Angstrom /sec.Torr as the result of the experience, the film having <=26 deg.DELTAtheta50'. Consequently, the two-layer film medium having the superior characteristics of <=18 deg.DELTAtheta50 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a perpendicular magnetic recording medium suitable for a perpendicular recording system.

A perpendicular recording method is a magnetic recording method with excellent short wavelength recording characteristics. This method requires a perpendicular magnetic recording medium having an axis of easy magnetization perpendicular to the film surface of the medium. When a signal is recorded on such a medium, the residual magnetization is oriented perpendicularly to the film surface of the medium, so that the shorter the wavelength of the signal, the smaller the demagnetizing field within the medium, resulting in excellent reproduction output. Perpendicular (1 company) A recording medium consists of a magnetic layer (hereinafter referred to as "magnetic layer") containing Go and Or as main components and having an easy magnetization of 1tGI+ in the direction perpendicular to the film surface, on a substrate made of a non-magnetic material such as a polymeric material or a non-magnetic metal. This magnetic layer (called a co-Or perpendicular magnetization film) is formed by sputtering or vacuum evaporation.

However, perpendicular magnetic recording media in which a Go-Or perpendicular magnetization film is formed directly on a nonmagnetic substrate (hereinafter referred to as a single-layer film medium) have low efficiency in recording and reproducing signals. To improve this, two-layer membrane media have been developed. This is a permalloy film having an axis of easy magnetization in the film plane between a nonmagnetic substrate and a Go-Or perpendicularly magnetized film. If a two-layer film medium having such a structure is used, the recording efficiency and reproduction efficiency can be improved by comparison with a single-layer film, and especially when recording and reproducing signals from a known sleeve-assisted magnetic pole excitation type vertical head. The efficiency improvement is remarkable.

In order to obtain a Go-Or perpendicularly magnetized film, it is necessary to align the C-axis of the dense hexagonal structure in a direction perpendicular to the film surface, but in the case of a two-layer film, the C-axis of the Go-Or film must be oriented The gender is
This affects the orientation of the underlying permalloy film. The reason for this is thought to be the effect of epitaxy during the formation of the GG-Or film.
In order to obtain an R film, a crystal must be grown so that the (111) plane of the NiHa Permalloy film is parallel to the film surface.

(111) In order to form a permalloy film with excellent orientation, on a Ti film deposited under a limited ratio X of the average deposition rate of the film and the oxygen partial pressure inside the vacuum evaporation apparatus,
As a result of experiments, it became clear that it was sufficient to form a permalloy film.

The present invention is a method for forming a permalloy film and a Co-Or film with excellent orientation thereon by vapor-depositing Ti while limiting X, that is, a method for forming a two-layer film medium with excellent properties. It provides:

The present invention will be explained below using FIGS. 1 to 4.

In a two-layer film medium, unless the half-width Δ05o of the rocking curve with respect to the (C02) plane of the Go-Or film is set to 18 degrees or less, the characteristics when recording and reproducing signals will be poor. An example is shown in FIG. It is thought that this represents the dispersion of the orientation of the ΔθSOVi (002) plane, and the smaller this value is, the better the orientation is. In Fig. 1, the vertical axis 1Ii is a two-layer film medium with a wavelength of 0.5.
The relative value of the output when recording and reproducing a μm signal is shown, and the horizontal axis shows the angle θ5o of the Go-Or film. An auxiliary magnetic pole excitation type perpendicular head was used as the trench recording and reproducing head, and the film thicknesses of the permalloy film and the Go-Or film in the two-layer film medium were both 0.2 μm. When Δθ5o exceeds 18 degrees, the output deteriorates rapidly. The cause of this is △OS
This seems to be because when O is 18 degrees or less, the residual magnetization of the Go-13r film is oriented perpendicular to the film surface, but when it exceeds 18 degrees, it is oriented in the film surface.

Figure 2 shows G on permalloy films with various orientations.

-Or film is formed (111
) half-width △θ50' of the rocking curve regarding the surface, and G
The relationship between the half-value width Δθ50 of the rocking curve for the (002) plane of the o-Or film is shown. From this figure, △θ5
In order to reduce 0, it is necessary to reduce △θ50', and in order to make △θ50 18 degrees or less, △θ
It can be seen that so' must be 26 degrees or less. That is, in order to obtain a two-layer film medium with excellent recording and reproducing characteristics, it is required that the Δ05o' of the permalloy film be 26 degrees or less.

As a result of experiments, when a permalloy film is formed on a Ti film deposited at a ratio X of the average deposition rate of the film and the oxygen partial pressure inside the vacuum evaporation apparatus of 1.6 x 1o6 = seconds/Torr, △ It has become clear that a film with θsd of 26 degrees or less can be obtained. This will be explained below.

Figure 3 shows the half-value width Δ05o of the rocking curve for the (002) plane of the Ti film and the (11
'1) Half width of rocking curve regarding surface △v50'
Indicates the relationship between From this figure, it can be seen that in order to make △θso' 26 degrees or less, △θ5o'' needs to be 14 degrees or less. When forming the T1 film by vacuum evaporation, d: The speed, type and amount of residual gas have a major influence on the orientation of the film.The inside of the deposition apparatus was made to have a vacuum of I x 10-6 Torr using a cryopump, and then argon was applied.

When nitrogen and oxygen were introduced into the evaporation apparatus, Ti was evaporated, and the characteristics were investigated, it became clear that the deposition rate of the film and oxygen had an effect. Argon and nitrogen are 2X
10-' Torr i was introduced and investigated, but Ti
No effect on the membrane was observed. The deposition rate and oxygen partial pressure of the film both affect the properties of the Ti deposited film.
Each of them was not independent, but had an influence in the form of these ratios. Figure 4 shows the relationship between △θ5o'' and You can understand the seconds and Torr that must be met.

As mentioned above, by setting X to 1.5 x 106 seconds Torr and depositing a Ti film, and forming a co-Or film on it via a permalloy film, A two-layer film medium with excellent characteristics, in which Δθ5° is 18 degrees or less, can be obtained.

Next, embodiments of the present invention will be described in more detail. X, ×,
A Ti film was prepared using the vacuum evaporation method as O.
θ50, △θ50' and △θ5o'' are each 7
The production method of the present invention produces a two-layer film medium with excellent properties suitable for perpendicular recording, as shown in the above example, which was excellent as a two-layer film medium at 9 degrees and 8 degrees. easily obtained.

[Brief explanation of the drawing]

Figure 1 shows the Δθ5o dependence of the output when a signal is recorded and reproduced on a two-layer film medium, and Figure 2 shows the 050 of the permalloy film when a Co-0r film is formed on the permalloy film.
' and Δθ5o of the Qo-Cr film, -3rd
The figure shows the relationship between Δθ5o" of the Ti film and Δθ50' of the permalloy film when a permalloy film is formed on the Ti film. Figure 4 shows the relationship between X and Δ/15G" of the Ti vapor-deposited film. FIG. Figure 1: tθso (degrees) Figure 2: θ (false)

Claims (1)

[Claims] A Ti film is formed on the substrate, and a permalloy film is formed on the Ti film, which has an axis of easy magnetization perpendicular to the film surface, and connects CO and Or
When manufacturing a perpendicular magnetic recording medium in which a magnetic layer mainly composed of A method for manufacturing a perpendicular magnetic recording medium characterized by a ratio of 1.5 x 10'.