JPS6068607A - magnetic thin film recording medium - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] This invention is optical (thermal) magnetic recording and thermomagnetic transfer.

This invention relates to a recording medium used in magnetic display elements and the like.

In a magnetic thin film recording medium having an axis of easy magnetization in 1) 5 directions perpendicular to the film surface, for example, by irradiating the light beam of a laser beam, the irradiated area is uniformly bowled in the S law or N pole. ,
Create an inverted magnetic domain with magnetic poles in the opposite direction to 1.
Information can be recorded by associating the presence or absence of this inverted magnetic domain with '1' and 'O'K. Information recorded in this way can be read using the magneto-optic effect.

Therefore, this type of magnetic thin film recording medium can be used as an R1 heel addressable file, but in use, it has a large retention force at room temperature, and it has a large retention force at room temperature, and is kept at a curie point or spindle temperature, or relatively room temperature. It is desirable to be able to form an inverted magnetic domain at an arbitrary position with a light beam using a single Curie point, gb, or temperature q1 near the Curie point.

Conventionally, polycrystalline metal thin films such as InB1 have been used as ferromagnetic thin films that have an easy axis perpendicular to the film surface, enable high-density magnetic recording, and can be used as beam atrezaple files. , compound single crystal thin films such as sulfuric carnet, Qd-Co, Gd-Fe, Tb-F
e.

There are amorphous thin films of red earth metals such as DY-Fe and Gd-Tb-Fe.

R*'? Mt I
h, ・C: i has a large coercive force of several KOe at room temperature, but is thermally unstable due to phase transformation, and has a high Curie temperature (MnB i ″′ck, f, Curie temperature 1. 'c = 3600), the laser power required for writing is as large as several tens of milliwatts, and the light scattering noise due to grain boundaries cannot be ignored. Thin J14
．． No. 4 has the disadvantage that it requires a large amount of energy to be injected, and since it is a single crystal, it is difficult to increase the area.

Furthermore, rare earth metals-transition metals:
In the exchange, the composition of the pleural membrane, d-Co, Gd-Fe, etc. Because of the strong dependence, it is difficult to produce a uniform 11!1 film on a large surface A]1i, and the recorded shield is unstable because the coercive force is small, ranging from several 10s to several 1,000e. There are disadvantages such as being

These polycrystalline metal thin films, compound crystal layers, and magnetically compensated temperatures are used to perform writing. Tb-Fe, Dy-Fe as medium.

A rare earth metal-transition metal amorphous thin film, such as Gd-Tb-Fe, which performs one-imposition using the Curie temperature, has been proposed. However, among these '1'b -pe
The Curie temperature is approximately 150°C, which is a little high to be avoided using a semiconductor laser, and the coercive force is also 200°C.
It is easy to manufacture products with characteristics that are somewhat too large, such as 0 to 55000e, but there are 11 points in which the bias magnetic field of 06 for writing must be increased.

In addition, Dy-Fe has a Curie temperature of about 70°C, which is too low, making it thermally unstable.
8000e, which is too small and the ability to retain recorded information is unstable. Furthermore, Gd-Tb-Fe has a Curie temperature of approximately 165° C., which is higher than that of Tb-Fe, making it unsuitable for writing using a semiconductor laser.

Tb -Dy -Fe is Curie temperature uso~150
℃e degrees, so it is possible to write with low-energy light, but it has the following drawbacks. In general, the reproduction force method that uses reflected light from these magnetic thin film recording media is popular, and the figure of merit 14゛, which is a guideline for the number-to-object ratio, is based on the reflectance of the medium being R and the Kerr rotation angle being θ. It is expressed by the following equation.

F=JR,・θk・(]) The disadvantage is that the Kerr rotation angle θk, which directly and linearly affects this figure of merit F, is as small as approximately 025° in the case of Tb −1)y−1;”e. .

This invention solves the drawbacks of the various recording media that have been proposed in the past, and adds Co to a Tb - Icy - Fe-based magnetic auxiliary film recording medium to
tl'! of Fe-based magnetic thin film recording medium! 1 length] - ta 1
Furthermore, the Kerr rotation angle was increased, and the curri temperature was increased to 80.
~150℃.

Coercive force 700-25000e, Kerr rotation angle 0.3
The object of the present invention is to provide a magnetic thin film recording medium of an amorphous thin film of all rare earth elements and transition metals, which allows the angle to be 0° or more.

This invention has a T
b -Dy -Co -F”e Consisting of a quaternary amorphous hexagonal alloy thin film, the atomic ratio of R1 of Tb and Dy in the total quaternary acid is 27 to 35 atoms, and the atomic ratio of CO is 1. ~35 atoms, the remainder is Fe, Tb in a binary acid consisting of Tb and Dy
This is a magnetic thin film recording medium characterized in that the composition has a composition in which the atomic ratio of .

DESCRIPTION OF THE PREFERRED EMBODIMENTS The magnetic thin film recording medium of the present invention will be described in detail below based on examples thereof and with reference to the drawings.

The magnetic thin film recording medium of the present invention comprises Tb-Dy'-Co
- It is formed by BQ in a quaternary amorphous alloy of Fe.

K makes the thin film amorphous to provide sufficient magnetic anisotropy to orient the magnetization direction perpendicular to the film surface. In order to stabilize the magnetization and maintain it perpendicular to the film surface, it is necessary to increase the film thickness to a certain extent. For this reason, in this invention, the phantom amorphous bamboo alloy thin film is formed to a thickness of several hundred angstroms or more by means such as sputter link method or vacuum deposition method.

Tb-Dy-Co-Fe quaternary amorphous alloy 'A'f
Ilk (D composition (%zDy1-X)yCozF
As a result of research and actual measurement of et-3'-Z and (2), the atomic ratios x+ y+ Z are 0.05≦x≦0.95 and 0.27<:y, respectively.
≦0.35.

It was confirmed that it is necessary to satisfy the relationship 0.01≦2≦0.35.

If we reduce the binary composition of Tb - Dy, we get Tb -
The atomic ratio X of Tb in the Icy binary acid is 005≦X≦095
If it deviates from this range, the coercive force and Curie temperature of the amorphous Jd gold alloy RM will rise too much, making it unsuitable for use as a so-called beam atrezaple file using a light beam. In addition, if the atomic ratio yK of Tb and Dy with respect to the total quaternary composition of a quaternary amorphous alloy thin film is taken sideways, if this deviates from the condition of 027≦y≦035, the coercive force becomes smaller and recording retention is reduced. Further, the perpendicular magnetization 1i51 becomes impossible. Also 027≦y
When the condition of ≦035 is satisfied, the obtained magnetic thin film recording medium has an angular B-(curve), can form a constant reversal magnetic domain in a predetermined magnetic field, and has desirable characteristics.

7 occupancy of Co in total a-acid in amorphous alloy thin film conversion, atomic ratio Z
When inspecting the hole, it is found that at Z<001, the effect of adding Co does not occur, and the Kerr rotation angle θk becomes 30° or less. Also, when Z increases to 0.35, the coercive force of the amorphous alloy thin film becomes too large, and the temperature of the amorphous alloy becomes too high, requiring a large amount of energy for writing, making it difficult to record. become unsuitable.

Figure 1 shows the composition, Curie temperature TC1, coercive force He, and Kerr rotation angle θk, respectively. This is an example of the JQ type j type of medium and field.

In FIG. 1, in the example of the actual color shown in Tsuta 15, Tb-Dy
This is a case where the atomic ratio X of b in the acid in the binary composition and the atomic ratio y of the total of Tb and Dy in the total quaternary composition are X=1 and y=Q, respectively. In this case, the thread outside of X≦0.95 is also 0.
The condition of 27≦y is also satisfied [2 is not satisfied. As a result,
In the figure, in the example shown in 412 (1), the atomic ratio Z of Co in the total quaternary composition is z = 0.004, and the condition required for ZK in this invention is 0.411≦Z is 4.
I'm not doing it unreasonably. In this case, Kerr rotation angle θ1 (=
At 0.25, the angle is less than 30°, which is not desirable for use as a beam atrezaple file. 1 apricot and 1 eggplant
In the example shown in 4, the co atomic ratio Z in the total quaternary composition is Z
= 0.41, and Φ cases of 2≦0.35 are jj1
Therefore, the coercive force of the amorphous alloy thin film l-
When Ic becomes an extremely large value of Hc-4500, the Curie temperature Tc also becomes a large value of 185, which is also not suitable for use as a beam atrezaple file.

FIGS. 2 to 4(2) show 1164. hω of FIG. 1 among actual examples of the magnetic thin film recording medium of the present invention. /167 and boiling 8 but not shown in the examples] 7 Its corresponding composition (1"bo
, 75Dyo25) 0.27 Coo, +s Fe
o, s5+ (Tbo67Dyo, C3) 0.32
Coo, 11F" o, s 7 + (Tbo43 D
5' 0.57 ) 0.33 C00,08""'
This is a Kerr hysteria/sloop shape for a recording medium that cures 0.59. In each case, the Kerr rotation angle θ is 1,043°, 0.400, and the Kerr rotation angle θ is 1,043°, 0.400.
and 036° and values of 0300 or more. In addition, in these examples, the Kerr hysteresis/sloop of each of the VJs has an angular shape, and when the magnetic field is returned to zero, it almost reaches a saturation value and exhibits excellent optical reproduction characteristics.

FIG. 5 shows the total composition of the magnetic saturation recording medium of the present invention (Tbo7s1.)yo2s)0.28 FeO,7
In the example represented by 2-z Coz, the relationship between the atomic ratio Z of Co in the total composition and the Kerr rotation angle θ is shown.3 In the example of FIG. 5, z = 0.05 or more, and θk
exceeds 03°, but generally by changing
It is possible to set k to exceed 03°.

As described above, the magnetic thin film recording medium of the present invention has a Curie temperature TC in the range of 80 to 150°C, and a coercive force He of 700 to 25,000e, 1.]1
In addition, the Kerr rotation angle θ can be set to 030° or more. Therefore, it is possible to infiltrate and erase recorded information using a low-energy laser beam without causing any heat-induced eroding of the magnetic duck film recording medium itself. It is possible to perform erasing, and by using a half-body laser, the magneto-optical disk recording cylinder can be made smaller (((□...).

In addition, since the easy axis is perpendicular to the film surface, high-density information storage is possible. Stability is also good. Furthermore, since the Kerr rotation angle can be increased, the optical reproduction output using the magneto-optic effect is also larger than before, which improves the signal-to-noise ratio and provides excellent characteristics. Pal recording media can be provided.

Since it is an amorphous alloy thin film, it can be formed on any substrate, and the atomic ratio of Tb in the Tb - Dy binary composition The Curie point Tc, the coercive force He, and the Kerr rotation angle θk can be adjusted by changing the atomic ratio Z of CO in the y1 total quaternary formation. In terms of manufacturing, since the permissible ratio of each component in the total four-element composition is relatively wide, there is no need to set strict ratio conditions, and manufacturing is easy and yields are high.

In addition, in the example, a laser beam was used as the infiltration method, but it is not limited to the IL beam, and it is also possible to use a heated sword, a frost beam, an ion beam, and other inverted magnetic domains. Any method that provides energy that can be generated can be used.

As explained in detail above, according to the present invention, high-density information storage is possible, the stability of recording + i11 information is high, and the signal-to-noise ratio is improved with a large raw output compared to the conventional method. It is removable and has high quality operating characteristics.
Furthermore, it becomes possible to manufacture a magnetic thin film recording medium whose magnetic properties can be adjusted by changing the hepatic ratio and whose manufacture is relatively easy.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the composition and characteristics of an embodiment of the magnetic thin film recording medium of the present invention, and FIGS. Figure 5 shows the formation of Kerr hysteresis loops corresponding to the example A, 7 and A, 8.
FIG. 3 is a diagram showing an example of the relationship between the atomic ratio of CO in the original composition and the horn rotation angle. x : Tb −])y 1゛b element −j in the binary composition
'-ratio, y: atomic ratio of the sum of '1'b and Dy in all the four-component silk y of the quaternary amorphous alloy thin film, Z: total 4 of the four-component thread amorphous and self-metallic anal. Atomic ratio of CO in the original acid, Tc: Curie temperature, Hc: coercive force 8, θ is the Niker rotation angle. 7F71 Figure No. 71 TC(”C) Hc(Oe)θk(1(
Tbo, 76Dyo, 24)o, 2acoo, oaFe
o, 64 ￥ J120 750 0゜2 (Tho, 57
Dyo, 43)o, 2sCoo, 1aFeo, s4 approx. 1
251890 0゜3 (Tbo, 5sDyo, 4s)
o, 26Coo, +aFeo, s6 approx. 125 800
0゜4 (Tbo, 7sDyo, 2s) o, z7coo
, 1aFe 130 800 0゜5 (Tb o, 5
s Dyo, 42) 0.30 Co o, o4Fe
O, 66 approx. 130 750 0゜6 (Tbo, 4sD
yo, 5s)o, 3ocoo, ++Feo, 59140
750 0゜7 (Tbo, 67Dyo, 33)o,
32Coo, ++Feo, s7 ladle 145 2400 0
゜8 (Tbo, 43Dyo, 57)o, 33coo,
oaFeo, 5q 135 1250 0゜9 (Tb
o, 37Dyo, 63) o, 33coo, osFeo,
5q 1152100 0.7) 72 Figure-'' 73 Oral Procedure Amendment 41- (Voluntary) October 31, 1980 1, Indication of the case Patent application No. 1703152, Title of the invention Magnetic thin film recording medium 3, Person making the amendment Relationship to the case Patent 1 11 monks Sumitomo Kinkaede Mining Co., Ltd. 4 Agent Sagami Building, 4-2-21 Shinjuku, Karijuku-ku, Tokyo: r, il' 5 Subject of amendment Detailed description of the invention column and the brief explanation column of drawings (5. Contents of amendment (1) page 8 of the specification, lines 6, 13, and 19, "Example")
Comparative example”.

Claims (1)

[Claims] Tb -Dy- having an axis of easy magnetization in the direction perpendicular to the film surface
Consists of a Co-Fe quaternary amorphous alloy thin film, with a total of 11 quaternary elements.
4↓In the composition, the atomic ratio of Tb and Dy on the gold side is 27 to 35 atoms, the atomic ratio of Co is 1 to 35 atoms, and the remainder is li'e, and the binary composition is Tb and Dy. The atomic ratio of medium Tb is 5
A sulfuric thin JliF self-recording medium characterized by having a composition of ~95 atoms.