JP3177281B2 - Magneto-optical recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rewritable magneto-optical recording medium, and more particularly to a composition structure of a recording layer.

[0002]

2. Description of the Related Art A magnetic film as a recording layer of a magneto-optical recording medium is formed by sputtering, as described in Japanese Patent Application Laid-Open No. 60-237655. FIG. 3 shows a schematic view of a conventional sputtering apparatus for producing a magneto-optical recording medium. As shown in the figure, a target 12 composed of a rare earth element and a target 13 composed of a transition metal are placed in a vacuum chamber 11.
Are arranged so as not to interfere with each other, and a substrate table 14 having a rotation mechanism is arranged at a position facing the substrates. The polycarbonate substrate 16 is rotated at a constant rotation speed on the substrate table 14 to obtain a structure in which rare earth metal layers and transition metal layers are alternately stacked.

[0003]

By the way, the magnetic properties of a magneto-optical recording medium have the same properties in a magnetic material. So,
When irradiating a laser beam for recording, heat transfer is delayed as the distance from the substrate side in the film thickness direction increases. As a result, when the inside of the domain is viewed, the magnitude of the magnetization varies in the film thickness direction. In addition, the Curie temperature also reaches the Curie temperature in a portion close to the substrate side but does not reach the Curie temperature in a portion away from the substrate when viewed over a certain period of time. Therefore, the direction of the magnetic field at the edge portion of the domain becomes unstable, which adversely affects the recording characteristics such as the CN ratio.

[0004]

According to the present invention, in order to solve the above-described problems, a recording layer mainly composed of GdDyFeCo, which is a rare earth-transition metal, formed on a substrate includes
In a magneto-optical recording medium in which 1 is added by substitution, the amount of Al added is continuously increased from the substrate side.

[0005]

According to the above means, the Curie temperature decreases as the distance from the substrate increases. Therefore, the entire domain simultaneously reaches the Curie temperature at the time of recording, and the domain is formed more quickly.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a magneto-optical recording medium according to one embodiment of the present invention. In the figure, a rare-earth metal-transition metal Gd is formed on a polycarbonate substrate 3 on which an SiN film 2 is formed.
A magnetic layer 1 containing DyFeCo as a main component is formed, and Al is added into the magnetic layer 1 while continuously increasing the amount of alloying. Then, an SiN film 4 is formed thereon.
It is protected by.

FIG. 2 is a Curie temperature characteristic diagram of the magneto-optical recording medium of the present invention. The figure shows the Curie temperature when the additive element Al is substituted in the magnetic layer 1 containing GdDyFeCo as a main component, and it can be seen that the Curie temperature decreases as the amount of Al added increases. Therefore, the recording layer can have a Curie temperature distribution by sequentially increasing the amount of Al as an additive element in the film thickness direction.

FIG. 4 shows a sputtering apparatus for producing a magneto-optical recording medium. In FIG. 4, a GdD
A target 17 made of a yFeCo alloy and a target 18 made of Al are arranged so as to interfere with each other at the time of sputtering, and a substrate table 14 having a rotating mechanism is provided so as to face these targets. High-frequency RF power supplies 15, 15 'are independently connected to the respective targets 17, 18 as sputtering power supplies. The polycarbonate resin substrate 16 is placed on the substrate table 14.
And rotated at a rotation speed of 30 rpm. GdD
yFeCo and Al interfere with each other so as not to form a laminated structure. GdDyFeCo is deposited at a constant rate, and the deposition rate of Al is continuously increased by increasing the power of the RF power supply, and the amount of Al added increases as the distance from the substrate increases. I do. Therefore, the Curie temperature of the medium has a distribution in the film thickness direction.

Incidentally, the present invention is not limited to the present embodiment, but a platinum group such as Pt, Pd, etc., and Co, Fe, Ni
A similar effect can be obtained by using an artificial lattice film in which transition metals such as are alternately stacked, and adding Al thereto.

[0010]

As described above, according to the present invention, the entire domain simultaneously reaches the Curie temperature at the time of recording, and the domain can be formed more quickly, so that the direction of the magnetic field of at least the domain is stabilized. And C
Improvement of recording characteristics such as N ratio can be expected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a magneto-optical recording medium according to an embodiment of the present invention.

FIG. 2 is a Curie temperature characteristic diagram of the magneto-optical recording medium according to the present invention.

FIG. 3 is a schematic view of a conventional sputtering apparatus for producing a magneto-optical recording medium.

FIG. 4 is a schematic diagram of a sputtering apparatus for producing the magneto-optical recording medium of the present invention.

[Explanation of symbols]

 Reference Signs List 1 magnetic layer 2 SiN film 3 polycarbonate substrate 4 SiN film (protective film)

Continuation of front page (56) References JP-A-3-201232 (JP, A) JP-A-3-216831 (JP, A) JP-A-3-49058 (JP, A) JP-A-2-118065 (JP) JP-A-60-251540 (JP, A) JP-A-63-100636 (JP, A) JP-A-3-62340 (JP, A)

Claims (1)

(57) [Claims] 1. A recording layer mainly composed of a rare earth metal-transition metal, GdDyFeCo, formed on a substrate,
A magneto-optical recording medium in which 1 is added by substitution, wherein the amount of Al added is continuously increased from the substrate side.