JPS59227052A - Photomagnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain an amorphous magnetic optical layer whose Curie temperature is low and whose Kerr rotational angle is large by constituting a titled medium so that at least cobalt of a specified atom % is contained in a Ta-Dy- Fe film or a Gd-Tb-Fe film having an axis of easy magnetization in the direction vertical to a film picture. CONSTITUTION:A magnetic optical layer is manufactured by forming a Tb-Dy- Fe film or a Gd-Tb-Fe film containing at least Co or 0.5atom%, on a nonmagnetic substrate consisting of glass, plastic, ceramics, etc. by a sputtering method, a vapor-depositing method, an ion plating method, etc. A target is constituted by placing a Tb, Dy and Co chip or a Gd, Tb and Co chip on an Fe circular pole by using, for instance, a composite method, and the composition is controlled by an area ratio of the target surface. In this way, since an amorphous magnetic optical layer contains Co, the Kerr rotational angle thetak becomes large up to 0.20-0.45deg, and an photo-magnetic recording medium having good reproducing characteristics is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an amorphous magneto-optic layer used in a magneto-optical recording medium.

-vtmaze-Sukiga Conventionally, ferromagnets (2
+ As a thin film, a multiviscous metal thin film represented by 8・I n 13 i, C,'= d −Co, (, d F'(
! Amorphous metal thin films such as those typified by the above, and compound 'N-1+'i thin films typified by GIG are known. Although these thin films have various advantages, M n B i requires a large amount of energy for writing due to its high Curie point, and also has the disadvantage that it is technically difficult to fabricate the thin film. In addition, (id-Co, Gd-Fe amorphous metal thin films have a small coercive force at room temperature (300-50(
l Oe) It has the disadvantage that the recorded information is unstable. Therefore, we developed a new magnetic thin film recording medium that eliminates the drawbacks of conventional magnetic thin film recording media as described above.
G d "I' l) - Fe having a ternary alloy thin film (see JP-A No. 56-126907) and G d "I' l) - Fe having an amorphous thin film (see JP-A-57-169945); Although these devices have advantages such as being able to write at Curie temperature, being relatively small and being able to write with a small laser power, Kerr (see publication) has been proposed.
The r) rotation angle (f) is small at 20-0.35 dcg, and the raw characteristics of r:ei are still not satisfactory.

The present invention has been made in view of the above-mentioned current situation, and its object is to provide an amorphous magneto-optical layer having a low Currency temperature and a large Curr rotation angle.

The amorphous magnetic sonic layer of the present invention is a Tb-1')y-Fe film or a G(IT
The b-Fe film contains at least 0.5 at.% of cobalt. In the present invention, the content of Kobal-111) is limited to at least 0.5 at% in order to obtain a large Kerr rotation angle. Therefore, the effects of the present invention cannot be achieved.

On the other hand, if the cobalt content is increased too much, the temperature will rise too much (1.5 to 20 atomic %) (l+' is preferable).

The magneto-optical R4 of the present invention is produced on a non-magnetic plate made of glass, plastic, ceramic, etc., or by a batter method, vapor deposition method, ion blating method, etc.
．． It can be produced by forming a TI+-Dy-Fc film or (id-Tb-Fe film) containing 5 elements r-% of Co. Targetera 1 can be produced using, for example, a composite method using a F″e0 disk. , J-ni'rb, Dyt,
J: UCo+ puma r, :1. tGd.

It is composed of Tb and Co chips, and the composition is determined by the area ratio of the target surface.

In addition, the magneto-optic layer of the present invention may be used as a magneto-optical layer #i! l! 11
．． For body use, it may be used alone or in conjunction with pond membranes. For example, the protective film is a film made of, for example, Sin, 5iO1Si, +N, etc.
I+-1)y Fe-Co film or Ci d-1"
It can be provided on the l+Fe, Co film by sputtering, vapor deposition, ion blating, or the like.

EXAMPLES The present invention will be specifically explained with reference to Examples below, but the present invention is not limited thereto.

Example 1 In this example, a TI]-Dy-Fe-Co film with a film thickness of approximately 20 mm was prepared on a slide glass under the following manufacturing conditions, and a compensation composition with a large Inc (Fe0. 79”
Fbo, 501) yO, 50) 0.2]') Kerr rotation angle (
Changes in θk) and Curie temperature (Tc) were observed.

<Production conditions> Residual gas pressure ', rj
orr)\fforce pressure: 1.5xlO-2To
rr discharge power: ,=l fl fl W press sputtering time: (if1min main sputtering time:
ff1lTllll force-rotation angle θ1(ha^(from the plate side l1
1, which was determined by the Kerr effect by irradiation with a c-Ne laser (λ = 6328 A), and the Curie temperature, 1°c, were measured using a vibrating sample type magnetization measuring device.

(1′″(+−XCoX)0.7g(i″l)0.50
1) yo, 50) 0C in 0.21 (l added charge × and θ1 (
Figure 1 shows the relationship between As is clear from this, c
When the amount of o added X increases, θ changes from 0.2 o deH to 0.
31 de8, but X-1,1, ] (l
(・It shows an almost saturated tendency near j, and after that, J, C.

Even if you add it, it won't be very effective. On the other hand, Curi one temperature'1
゛(As shown in Figure 2, increase the amount of Co added 1 and 9.
＋) 'C-gara 1 ri (straight line to 1'C')
Do 1. If i'c is too high, more energy is required, resulting in poor recording sensitivity. In this example, θk or x
Since it shows a tendency to saturate near = 0.1041, Tc
is not too high.

It can be concluded that the approximate value is the optimum condition where θ1 is large and Tc is low.

Example 2 In this example, the following manufacturing conditions were used:
C1d-TI with a film thickness of 200 (l)\]Fe
-Co film was prepared] -1c large compensation composition 1;
The Kerr rotation angle 1j (θk) and the Curie temperature 1 when part of Fe is replaced with Co in a composition of 0.21
We looked at the changes in (c).

<Production conditions> Residual gas pressure: 8 x 11) -? TorrAr gas pressure: 1.5xlO-2i'orr discharge force
: 401) w Press buff time: 60m group Main sputter time: L3 III j II Deer turning angle and Curie temperature! The full constant was measured in the same manner as in Example 1. (Fe film-xCox) 0.79 (
The relationship between the Co addition amount X and θ in Gdo, 5oTIJo, 5o)0.21 is shown in FIG. As is clear from this, when the Co addition amount x is increased, θ increases from 0.35 deε to 0,45 deB, or x = 0, 1
．． It shows a tendency to saturation near O[=l, and beyond that point, there is no effect even if J2CO is added. On the other hand, the Curie temperature] ゛c becomes 160'C as the Co addition amount X is increased, as shown in Figure 4.
The temperature rises linearly from 240 to about 240"C. If Tc is too high, recording energy is required, resulting in poor recording sensitivity. From the following results, the optimum value for the amount of CO added x is 0.
08~O, ] (It can be concluded that l.

For example, since the amorphous magneto-optic layer of the present invention contains Co, the Kerr rotation angle θ1 (~'0.2O-(1.45 deB) can be reached, thereby providing a magneto-optical recording medium with good reproduction characteristics. ·Wear.

[Brief explanation of drawings]

FIGS. 1 to 4 are diagrams showing the relationship between the Kerr cycle 1 and the Curie temperature, which are related to composition changes in determining the optimum conditions for the magneto-optic layer of the present invention. Co3 supplementary quantity L Co Yukari quantity Co > Excitation quantity Otsu Co travel quantity atsu

Claims (1)

[Claims] Tb-1)y- having an axis of easy magnetization in the direction perpendicular to the film surface
An amorphous magneto-optical layer comprising at least 0.5 atomic % of cobalt in the Fe film or the G d i "l+ Fe film.