JPS59215478A - Amorphous magneto-optical layer - Google Patents

Abstract

PURPOSE:To obtain an amorphous magneto-optical layer having a low Curie temp. and a large angle of Kerr rotation incorporating a proper amount of Co into a Dy-Fe film having an axis of easy magnetization. CONSTITUTION:At least 0.5 atomic% Co is incorporated into a Dy-Fe film having an axis of easy magnetization in a direction perpendicular to the surface of the film to obtain an amorphous magneto-optical layer. In case of <0.5 atomic% Co content, a sufficient angle of Kerr rotation is not provided, and a higher Co content raises the Curie temp., so the preferred Co content is 0.5-20 atomic%. The amorphous magneto-optical layer is suitable for use as a photomagnetic recording medium or the like.

Description

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

Prior Art Conventionally, as ferromagnetic thin films having an axis of easy magnetization perpendicular to the film surface, polycrystalline metal thin films represented by MnB1, Gd
Amorphous metal thin films represented by -Co, Gd-Fe, etc., and compound single crystal thin films represented by GIG are known. Although these thin films have various advantages, MnB1 has the disadvantage that it requires a large amount of energy for writing and is technically difficult to fabricate thin films due to its single Curie point. However, amorphous metal thin films such as Gd-Co and Gd-Fe have a small coercive force at room temperature (300 to 50
00e) has the disadvantage that the recorded information is unstable. Therefore, we developed 18 as a new magnetic thin film recording medium that eliminates the drawbacks of conventional magnetic thin film recording media as described above.
An amorphous Dy-Fe alloy film containing ~28 atoms of Dy has been proposed (Japanese Patent Publication No. 57-20692).
(see publication). This alloy film has a Curie temperature Tc of approximately 70
Since the C is low, it is possible to write with a small laser power, but the Kerr rotation angle θ1 (0°1
There was a problem in that it was small, around 5 deg, and it was not possible to obtain a sufficient reproduction output.

Purpose The present invention was made in view of the above problems, and its purpose is to provide an amorphous magneto-optical layer having a low Curie temperature and a large Kerr rotation angle.

The amorphous magnetic C-shaped layer of the present invention contains at least 0.5 atoms of cobalt in a Dy-Fe film having an axis of easy magnetization perpendicular to the film surface. The content of cobalt is limited to at least 0.5 atomic tons because
The purpose is to obtain a large Kerr rotation angle, and if it is less than 0.5%, a sufficient Kerr rotation angle will not be obtained and the effects of the present invention will not be achieved.

On the other hand, if the cobalt content is slightly increased, the Curie temperature will be too high, so the range of 05 to 2 (] atoms is preferable.

The magneto-optical layer of the present invention is formed on a nonmagnetic substrate made of glass, plastic, ceramic, or the like.

Dy-Fe containing at least 0.5 atoms of Co and f by sputtering, vapor deposition, ion blating, etc.
It can be produced by forming a film. Preferably, the film is formed by sputtering. For example, the target is combojitsu!・Using the method, Dy and CO deposits are deposited on an Fe disk, and the composition is controlled by the area ratio of the target surface. In addition, when the magneto-optic layer of the present invention is used in a magneto-optical recording medium, it may be used alone or together with another (1). Lee Rieba 5102
Dy-Fe-
C.

- It can be provided on the film by sputtering, vapor deposition, ion blating, etc.

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

In this example, 2 (
A film with a film thickness of 1001 mm was prepared, and a complementary film with a large Hc was prepared.
Changes in the Kerr rotation angle θ and the Curie temperature Tc were observed when part of Fe was replaced with Co in a composition of Fs 0078 Dy O, 22 near the composition.

<Production requirements> Residual gas pressure: 8X 10-7 TorrAr gas pressure:
２
6s2sX ) was irradiated and determined by the Kerr effect.

Further, the cu-91 temperature Tc was measured using a vibrating sample type magnetization measuring device. (Fe 1-XCOX) 0.78 DY
o, 22 width C.

As is clear from the results shown in Figure 1, which show the relationship between the amount of Co added and θ, when the amount of Co added is increased, θ increases by 0.15.
deg by 0.28 deg, but it showed an almost saturated tendency around x=0.10. On the other hand, Curie Wen JiTc
becomes 70 as the Co addition J' x is increased as shown in Figure 2.
The Tc of the magneto-optical recording medium increases almost linearly from °C.
A temperature in the range of 100 to 200°C is considered suitable; however, if the temperature is too high, a large amount of recording energy is required, which is disadvantageous. In this example, since θk shows a tendency to saturate around X=0.10, Tc does not become too high when x=0.10.
It can be concluded that a value around 1[] is the optimum condition where θk is large (Tc is low).

Effects The amorphous magneto-optic layer of the present invention has the effect of providing a magneto-optical recording medium with a low Curie temperature and a large Kerr rotation angle.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams respectively showing 11 systems of Kerr rotation angle and Curie temperature/pressure with respect to changes in composition for determining the optimum conditions for the magnetic 9°C layer of the present invention. Patent applicant Riko Co., Ltd.

Claims (1)

[Claims] An amorphous magneto-optical layer comprising at least 0.5 atoms of cobalt in a D7-Fe film having an axis of easy magnetization in a direction perpendicular to the film surface.