JPS59175020A - Thin metallic film type magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a thin metallic film type magnetic recording medium having good efficiency in the recording and reproducing process by a ring type gap head by providing a ferromagnetic layer satisfying prescribed conditions on a substrate. CONSTITUTION:A thin ferromagnetic film layer II is formed on a high polymer substrate I , and the angle theta between the C-axis III of the crystal particles thereof and the substrate plane is set at 40-65 deg. to make the size HK of an anisotropic magnetic field larger than 4piMs with respect to the satd. magnetic field Ms of a magnetic material. For example, Cr is used as an element 10 in a vessel 9 for the vapor deposition source in a vapor deposition devide 14 and Co is used as an element 11. A Co-Cr film (0.2mum) is deposited by evaporation on an ethylene terephthalate substrate (10.5mum thickness) I via a high frequency coil 8 by ion plating. The vapor deposition speed is set at 800Angstrom /s for Co and 240Angstrom /s for Cr and the Co-Cr film having about 3,000 gauss 4piMS is obtd. The thin metallic film type magnetic recording medium having good recording and reproducing efficiency is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application Kinori 1 relates to a metal thin film type magnetic recording medium used as a magnetic recording medium having excellent short wavelength recording characteristics in sound recording, video recording, information processing, etc.

Conventional configurations and their problems Traditionally, magnetic recording media have been made of CO-doped γ-FezOs or Cr on a polymer substrate or an aluminum substrate.
(So-called coated type materials, in which powdered magnetic materials such as oxide magnetic powder such as H, or ferromagnetic alloy powder such as P, are dispersed in an organic binder such as polyurethane resin, and then applied and dried are widely used in Amagawa. ing.

However, in recent years there has been a strong demand for recording density, and the technical limits of recording density in systems using conventional coated media are beginning to be seen, and testing of systems using new media has begun.

The new medium is a so-called metal thin film magnetic recording medium, which uses a ferromagnetic metal thin film as a magnetic recording layer, which has long been noted for its excellent short wavelength recording characteristics, and has been put into practical use as short wavelength recording characteristics have been renewed. Efforts are continuing toward this, and at present, the most advanced research is on Co-N1-()-based obliquely deposited films and Co-Cr-based sputtered films. The former is magnetized in-plane due to the demagnetizing field and is called a so-called in-plane magnetized film.In CO-Cr sputtered films, the C axis (principal axis) is almost perpendicular to the substrate surface due to manufacturing conditions. It is thought that higher density recording is possible because there is less loss due to demagnetizing fields, and it is called a perpendicular magnetization film.

However, from a practical point of view, these media have the best narrow f-sep, such as a ferrite head with an f-jump length of 025 μm.
When we examine in detail the memorization and heating characteristics of ring heads such as the Centast head, we find that the actual situation is that satisfactory external output is not necessarily obtained, and when compared with conventional coating, it is overwhelmingly Although it has an advantage in short wavelength output, in order to take full advantage of the characteristics of the metal thin film type in a practical system, a new medium configuration is required to replace the currently known media.

OBJECTS OF THE INVENTION An object of the present invention is to provide a metal thin film type magnetic recording medium that is efficient in the recording and reproducing process using a ring type narrow f-Sev head.

The metal thin film magnetic recording medium according to the invention has a ferromagnetic layer on a substrate fK, and the main axis of the constituent crystal grains of the ferromagnetic layer is inclined at an angle of 40° or more to 65° or less with respect to the substrate surface. , the anisotropic magnetic field HK satisfies the condition that the anisotropic magnetic field HK is greater than 4πMS, where MS is the saturation magnetization.

The substrate used in the present invention is made of polyethylene terephthalate, polyethylene naphthalate, triboria, polyimide, polycarbonate, etc., or these polymer substrates E
and a non-magnetic underlayer or a soft magnetic underlayer. Note that there are no particular limitations on the manufacturing method of the nonmagnetic underlayer and the soft magnetic layer, and known electron beam evaporation methods, sputtering methods, ion blating methods, ion beam evaporation methods, wet plating methods, etc. can be used as appropriate.

The ferromagnetic materials used in the present invention are Co-Cr, Co-N
iCr'i-'cO-Mo, Co-V,
Cr, Mo
The structure of the present invention can be obtained by selecting the contents of , V, W, etc. to lower the MS and performing oblique deposition at a specific angle, but the coercive force is large unless the manufacturing conditions are carefully examined. Coercive force cannot be easily obtained. The most reliable method is to use an endless belt as a rotating support and perform ion bombardment under conditions where the incident angle is almost constant, or to raise the substrate temperature, or to use a combination of both. realizable.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the cross-sectional structure of the completed magnetic recording medium, which is a medium in which a ferromagnetic thin film layer (11) is disposed on a substrate (I) such as a polymer substrate. As shown in the figure, if θ is the angle that the C axis [phase] of the crystal grains constituting the ferromagnetic thin film layer makes with the substrate surface, θ is adjusted to 40° or more and 65° or less, and If the saturation magnetization of the material constituting this thin film layer (2) is Ms, and the magnitude of the anisotropic magnetic field is HK, then HK is 4πM
It is made up of conditions that are greater than S.

FIG. 2 shows the main structure of a winding vapor deposition apparatus used to obtain the medium having the structure shown in FIG. The polymeric substrate (I) is configured to undergo deposition as it moves along a rotating support, where the rotating support is rotatably cooled (2) (
3) and a metal endless belt (4), and the endless belt (4) is rotated at a constant speed in the direction shown by the arrow. In addition, the inclination of the endless belt (4) can be adjusted, and the inclination of the endless belt (4) can be adjusted.
The angle of the C-axis is selected to a preferable condition by adjusting the angle of incidence of the vapor flow either by adjusting the position in step 5) or by adjusting the angle of incidence of the vapor flow. Note that the substrate (I) is arranged to move from the feed shaft (6) to the winding shaft (7) along the endless belt (4).

An alloy evaporation source (g) that generates the vapor flow is arranged opposite to the substrate (1), and a high frequency coil (8) for ion bombardment is arranged between the two. The evaporation source container (9) for the alloy evaporation source α) is a two-tank type, charged with A element and B element αυ, and A element GO and B
The structure is such that each element Al can be individually impact-heated using an electron gun.

Note that the A element 4 and the B element CIυ are not necessarily single elements, but may be alloys with similar vapor pressures.
Of course, the amount of evaporation of element B may be adjusted.

These systems are installed inside the vacuum tank a-glue, and the vacuum! (The inside of 14 is exhausted by the exhaust system Q.

Al is a high frequency power supply, and σ is an insulating introduction terminal.

Example 2 In the second worst device, the element αQ is set to Cr, and the B element al is set to C.
A Co-(:r) film of 02 μm was obtained on polyethylene terephthalate 110R11 as a substrate (I) using a high frequency ion plater.
50 W input, vapor deposition 4 degrees 1icolsi 800
X/sec, Crt>i 240 X/sec. By changing the input and tA conditions, the value ACo-(r) of the 4-film Ms of about 8000 Gauss was obtained under the E conditions, and the substrates (I) were each cut into 8 regular widths to make magnetic tape. Figure 3 shows the results when the receiver is modified and recording/reproduction is performed using a ferrite head with a ferrite head with a tongue length of 02 μm, with the in-plane magnetization film of the Co-N1 ( ) system closest to the practical level as OdB. Ta. The Co-Ni-0 film used had a thickness of 0.
．． 13μm, Hc=1000 [OeJ, 4 films Ms=
It is 8,700 ri.

The shorter the wavelength, the more accurate it is to correct space loss.
Since this was not possible, the same substrate was used for all the tests, and the surface roughness was adjusted to the same level of film forming accuracy as t.

For reference, a perpendicularly magnetized film was also manufactured using the same substrate as the product of the present invention, and its appearance was also shown.

In addition, it was obtained from the M-H curve in the in-plane direction of Hxtj, but 50
00 g)eJ to 58001e].

Further, the value in the Hc&iC axis direction was 10oo [1050th eJ from OeJ.

From Figure 8, the high output area due to the ring head is in the range from 40° to 653°, and the transition area is from 30° to 40°, 65°.
It can be seen that the angle ranges from 5° to 75°. This is thought to result from the magnetic field distribution generated by the ring head, and indicates that the conditions for matching the magnetic field gradient to maximize recording efficiency are neither in-plane magnetized films nor perpendicularly magnetized films. This tendency was the same for the blank head and the amorphous head.

Example: A tri-borium substrate (8 μm) was pre-treated with Ar ions 2
+ Bombarded, (Ar ion concentration 'lOμ~'am
, Ar ion energy L f-IKeV ), element αQ
is Cr, 8 elements Ql) is an alloy of 80% Co and 20% Ni, and Cr is 140%. A/see.

It was evaporated at 0.028 pm at 400 A/sec. , high frequency ion plaity with high frequency power 800W, 7rishi f
C6 Changing the incident angle under the above conditions, θ=20? θ=30?
θ=38°, θ=36ζθ=38ζθ=40°, θ=4
2ζθ=45-σ=50ζθ=60ζθ=63;θ=6
5 ζ θ = 665 ζ θ = 68°, θ = 70°, 15 levels of Co→J i −(r films were manufactured. 4 films Ms were approximately a
eoo 1us, HKke approx. 6000 ie” and Hcke 1
It was 121010eJ from 150[OeJ.

As a comparative example, a Co-Ni-0 in-plane magnetized film (4 films M
s=890of5us, Hc=1200 [Oel)
, CoCr perpendicular magnetization II'-! (4yrMs=890
0) 1us, l1c=12500e] ) was also produced,
Each tape had a width of gtnm and was compared using an eyelid tester. The head uses an amorphous head with an instep length of 0.18 μm and a ferrite head, and a recording wavelength (182 μm).
A relative comparison was made using the Co-N1-() film as OdB. As a result, the medium according to the present invention had a high output of nearly +6df3. The transition region also appeared more prominently in the third flash. In this case as well, the high output range close to +6 dB was in the range of θ from 40° to 65°.

Note that the output of the perpendicularly magnetized film was +2 dB in this case.In the above embodiment, nothing was provided in addition to the ferromagnetic thin film layer Φ), but the durability and weatherability of the medium were higher than that of the ferromagnetic layer alone. If this is not satisfactory, it is of course possible to arrange an organic N film on the surface as appropriate.

In addition, in Example 1, the ferromagnetic thin film layer Φ) is arranged only on one side of the substrate (I), but this is different from the case where the same ferromagnetic layer is arranged on both sides of the substrate, or where one side is completely perpendicularly magnetized. It is possible to arrange a thin film magnetic layer such as a film or an in-plane magnetized film, or a coated magnetic layer obtained by a coating method so that it can be accessed from both sides simultaneously or separately.

As described in the detailed description of the invention, according to the metal thin film magnetic recording medium of the present invention, a ferromagnetic layer is provided on a polymer substrate, and the main axis of the crystal grains constituting the ferromagnetic layer is at an angle of 40° or more with respect to the substrate surface. Since the configuration is such that the anisotropic magnetic field HK is greater than 4 films Ms, if the saturation magnetization is MS,
It can obtain high output at short wavelengths, and can also achieve higher output than that of perpendicular magnetization films under conditions where it is easy to establish an interface using technology that is an extension of conventional technology. This can dramatically promote the miniaturization of equipment in industry.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of one embodiment of the magnetic recording medium of the present invention, Figure 2 is a main part configuration diagram of the winding vapor deposition apparatus used to obtain the magnetic recording medium of Figure 1, and Figure 88 is a sectional view of an embodiment of the magnetic recording medium of the invention. FIG. 2 is a diagram showing the relationship between short wavelength output and θ of the magnetic recording medium of the present invention. (I)...Substrate, 11)...Ferromagnetic thin film layer, 10.
...main axis of crystal grains constituting the ferromagnetic thin film layer, (4)...endless belt, (5)...mask, (6)...feeding shaft, (7)...winding shaft, (9)... ...Vapor deposition source container, <1 (1...A element, αυ...B element agent
Yoshihiro Yoshiki Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] l. A ferromagnetic layer is provided on the substrate, and the main axis of the crystal grains constituting the ferromagnetic layer is inclined at an angle of 400° to 65° relative to the substrate surface, and when the saturation magnetization is MS, the anisotropic magnetic field HK is 4πM
A metal thin film magnetic recording medium that satisfies the condition greater than s.