JPH05205328A - Magnetooptical recording medium - Google Patents

Abstract

PURPOSE:To simultaneously make the total domain arrive at a Curie temp. at the time of recording and to quicken the formation of the domain by adding a substituting element to a recording layer of a magnetooptical recording medium so as to make it increase cantinuously from a substrate side and having the structure that the Curie temp. becomes low as it aparts from the substrate. CONSTITUTION:In the magnetooptical recording medium in which at least one kind of the group selected from B, C, Al, Si, P, Ti, V, Fe, Ni, Cu, Ga, Ge, Zr, Nb, Mo, In, Sn, Sb, Gd, Tb, Dy and Ta is added by substitution to the recording layer of the magnetooptical recording medium which enables to perform a thermal magnetic recording, and the magnetooptical recording medium in which the added quantity of the substituted element is continuously increased from the substrate side.

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, which is a recording layer of a magneto-optical recording medium, is formed by sputtering as described in JP-A-60-237655. FIG. 3 shows a schematic view of a sputtering apparatus for producing a conventional magneto-optical recording medium. As shown in the figure, a vacuum chamber 11 has a target 12 made of a rare earth element and a target 13 made of a transition metal.
Are arranged so as not to interfere with each other, and the substrate table 14 having a rotation mechanism is arranged at a position facing each other. The polycarbonate substrate 16 is rotated on the substrate table 14 at a constant rotation speed to obtain a structure in which rare earth metal layers and transition metal layers are alternately laminated.

[0003]

By the way, the magneto-optical recording medium has the same magnetic characteristics in the magnetic body. So
When a laser beam is irradiated for recording, the heat transfer is delayed as the distance from the substrate side in the film thickness direction increases. As a result, when viewed inside the domain, the magnitude of magnetization varies in the film thickness direction. Regarding the Curie temperature, when viewed over a certain period of time, the Curie temperature reaches the Curie temperature in the portion close to the substrate side, but does not reach the Curie temperature in the distant portion. 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, B, C, Al, Si, P, Ti, V, Fe, Ni, C are contained in a magnetic layer.
u, Ga, Ge, Zr, Nb, Mo, In, Sn, S
At least one metal element of b, Gd, Tb, Dy, and Ta is added while continuously increasing from the substrate side in the film thickness direction.

[0005]

By the above means, the Curie temperature is lowered as the distance from the substrate increases. Therefore, during recording, the entire domain reaches the Curie temperature at the same time, which accelerates the formation of the domain.

[0006]

The present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a magneto-optical recording medium according to an embodiment of the present invention.
In the figure, a rare earth metal-transition metal, GdDyFeC, is formed on a polycarbonate substrate 3 having a SiN film 2 formed thereon.
A magnetic layer 1 containing o as a main component is formed, and Al is continuously added to the magnetic layer 1 while alloying while increasing the addition amount. Then, the SiN film 4 is provided thereon for protection.

FIG. 2 is a Curie temperature characteristic diagram of the magneto-optical recording medium of the present invention. In the figure, additional elements B, C, A
l, Si, P, Ti, V, Fe, Ni, Cu, Ga, G
e, Zr, Nb, Mo, In, Sn, Sb, Gd, T
The Curie temperature when b, Gd, Tb, Dy, and Ta are replaced is shown, and it is understood that the Curie temperature decreases as the addition amount of each element increases. Therefore, the Curie temperature distribution can be provided in the recording layer by sequentially increasing the addition amount of these elements in the film thickness direction.

FIG. 4 shows a sputtering apparatus for producing a magneto-optical recording medium. In FIG. 4, GdD is added to the vacuum chamber 11.
A target 17 made of 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 installed so as to face these targets. High-frequency RF power sources 15 and 15 'are independently connected to the targets 17 and 18 as sputtering power sources. The polycarbonate resin substrate 16 is attached to the substrate table 14
It is attached to and is rotated at a rotation speed of 30 rpm. GdD
yFeCo and Al interfere with each other to prevent a laminated structure. GdDyFeCo is deposited at a constant rate, and the Al deposition rate is continuously increased by increasing the power of the RF power source, so that the Al addition amount increases as the distance from the substrate increases. To do. Therefore, the Curie temperature of the medium has a distribution in the film thickness direction.

The present invention is not limited to this embodiment, but the magnetic layer contains platinum group such as Pt and Pd and Co, Fe and Ni.
Similar effects can be obtained by using an artificial lattice film in which transition metals such as the above are alternately laminated and adding Al thereto.

[0010]

According to the present invention, recording can be performed at a high transfer rate and recording noise can be reduced.

[Brief description of 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 sputtering device for producing a conventional magneto-optical recording medium.

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

[Explanation of symbols]

 1 Magnetic layer 2 SiN film 3 Polycarbonate substrate 4 SiN film (protective film)

Claims (1)

[Claims] 1. B, C, Al, Si, P, Ti, V, F in a recording layer of a magneto-optical recording medium capable of performing thermomagnetic recording.
e, Ni, Cu, Ga, Ge, Zr, Nb, Mo, I
In a magneto-optical recording medium in which at least one of n, Sn, Sb, Gd, Tb, Dy, and Ta is added by substitution, a magneto-optical recording medium in which the addition amount of a substitution element is continuously increased from the substrate side.