JPH04351733A - Magneto-optical recording medium - Google Patents

Abstract

PURPOSE:To improve the coercive force of the magneto-optical recording medium having a structure formed with Pt layers on the substrate side of recording films and to allow recording at a higher density. CONSTITUTION:A transparent compd. which is the structure of any among sphalerite type structure, wurtzite type structure, nickel arsenide type structure, titanium phosphate type structure, and tungsten carbide type structure is inserted as a substrate layer 2 between the substrate 1 and Pt layer 3 of the magneto- optical recording medium having the structure formed with the Pt layers 3 on the substrate 1 side of the recording films. The orientability of the Pt is improved in this way and the coercive force of the recording films is increased. Then, the high-density recording is possible.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides Pt on the substrate side of the recording film.
The present invention relates to a magneto-optical recording medium having a layered structure.

0002

2. Description of the Related Art Examples of magneto-optical recording media having a Pt/Co laminated structure according to the prior art are shown in FIGS. 2 and 3. In Figure 2, a base layer (Si3N4) 4 is formed on a substrate 1 made of glass or PC (polycarbonate) in order to increase the Kerr effect, and an etching treatment 5 is applied to smooth the surface of the formed base layer 4. Then, on top of that, Pt and Co are formed as a Pt layer, a Co layer,
..., Pt layers are laminated in this order (14th Japanese Society of Applied Magnetics, Abstracts of Academic Lectures (1990), p. 65 "P
Microstructure of t/Co stacked film” Sumi et al.). In such a magneto-optical recording medium, Si3N4 is amorphous and P
The t-layers are not neatly stacked in the [111] direction. Therefore, the perpendicular magnetic anisotropy is small, and a coercive force of only about 1 kOe can be obtained.

In addition, GaAs6 and Pt as shown in FIG.
There is a report that the coercive force of a magneto-optical recording medium with a Pt/Co stacked structure was increased to 4 kOe by using Pt/Co as an underlayer (E-MRS spring '90
CVIII-7), GaAs, and Pt are opaque, so if such an underlayer is provided, signals cannot be read out.

0004

SUMMARY OF THE INVENTION The present invention has been made to solve these problems, and provides a magneto-optical recording medium having a structure in which a Pt layer is formed on the substrate side of the recording film.
This increases the coercive force.

[0005]

[Means for Solving the Problems] In a magneto-optical recording medium having a structure in which a Pt layer is formed on the substrate side of a recording film, the present invention provides a magneto-optical recording medium having a cenaeite type structure, a wurtzite type structure, a nickel arsenide type structure, a titanium phosphide type structure, A transparent compound having any of the tungsten carbide type structures was used as the underlayer.

[0006]

[Operation] In the magneto-optical recording medium of the present invention, when forming a recording film, since the crystals of the underlayer are arranged in a dense manner, if a Pt layer is formed on the underlayer by sputtering or the like. The Pt layers are also arranged densely. This increases the coercive force of the recording film and enables high-density recording.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional structural diagram of a magneto-optical recording medium having a Pt/Co laminated structure according to the present invention, in which a base layer 2 is formed on a substrate 1, and a Pt layer and a Co layer are further formed on the base layer 2. layer,
..., a Pt/Co laminated film 3 is formed in the order of the Pt layer. The base layer 2 was made of a transparent compound having any one of a senaenite structure, a wurtzite structure, a nickel arsenide structure, a titanium phosphide structure, and a tungsten carbide structure.

The Pt crystal has a face-centered cubic lattice as shown in FIG. 4, and when viewed from the [111] direction, it has a close-packed stacked structure as shown in FIG. The lattice constant is 3.9 Å, and the interatomic distance is 2.8 Å. If the arrangement of atoms on the surface of the underlayer is similar to the plane of Pt viewed from the [111] direction, the orientation of Pt will improve.

FIGS. 6 to 10 show crystals in which a certain plane of the crystal is arranged in the same manner as the plane of Pt viewed from the [111] direction. FIG. 6 shows a cubic senaeite-type structure, which when viewed from the [111] direction, is arranged in a dense arrangement similar to Pt. 7 shows a wurtzite structure, FIG. 8 shows a nickel arsenide structure, FIG. 9 shows a titanium phosphide structure, and FIG. 10 shows a tungsten carbide structure, all of which are hexagonal crystals, and when viewed from the [0111] direction, P
They are arranged in the same dense arrangement as the surface viewed from the [111] direction of t. Therefore, for those with the above crystal structure, the cubic lattice constant is around 3.9 Å, and the hexagonal lattice constant is around 2.8 Å.
If a nearby layer is used as a base layer and a Pt film is formed on it, the Pt layer will also be formed in a close-packed structure. Figure 1
1 shows P when the surface of the underlayer is significantly different from the surface seen from the [111] direction of Pt, and FIG. 12 shows P when it is similar.
This figure shows the state of the interface between the t-layer and the underlayer. Here, 7 is a Pt atom, and 8 is an atom of the underlayer. Figure 12 shows P
The film is formed while t is arranged in the closest arrangement.

Table 1 shows examples of compounds used in the underlayer of the magneto-optical recording medium having a Pt/Co laminated structure according to the present invention.

0012

[Table 1]

FIG. 13 shows a magneto-optical recording medium 9 with a Pt/Co multilayer structure using AlN as an underlayer among the compounds in Table 1 and a magneto-optical recording medium 9 with a Pt/Co multilayer structure according to the prior art (with Si3N4 as an underlayer). Fig. 10 is a characteristic diagram of the sample used as From FIG. 13, it is clear that Pt/Co according to the present invention
It can be seen that the magneto-optical recording medium with the laminated structure has an increased coercive force.

Similar effects can also be obtained when a compound other than AlN shown in Table 1 is used as the underlayer.

The recording film of the magneto-optical recording medium has a laminated structure of a magnetic material other than Co (for example, Fe) and Pt, or a structure in which a Pt layer is formed on the substrate side of a magnetic film (for example, rare earth-transition metal alloy). It may be.

[0016]

Effects of the Invention According to the present invention, Pt is formed on the substrate side of the recording film.
In a magneto-optical recording medium having a layered structure, the orientation of Pt is improved and the coercive force of the recording film is improved. the result,
High-density recording becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional structural diagram of a magneto-optical recording medium having a Pt/Co laminated structure according to the present invention.

FIG. 2 is a cross-sectional structural diagram of a magneto-optical recording medium with a Pt/Co laminated structure using Si3N4 as an underlayer.

FIG. 3 is a cross-sectional structural diagram of a magneto-optical recording medium with a Pt/Co laminated structure using GaAs as an underlayer.

FIG. 4 is a schematic diagram showing the crystal structure (face-centered cubic lattice) of Pt.

[Figure 5] Pt crystal of Figure 4 viewed from [111] direction
FIG. 3 is a diagram showing how crystals are stacked.

FIG. 6 is a schematic diagram showing the crystal structure of a compound having a senaeite structure.

FIG. 7 is a schematic diagram showing the crystal structure of a compound having a wurtzite structure.

FIG. 8 is a schematic diagram showing the crystal structure of a compound having a nickel arsenide type structure.

FIG. 9 is a schematic diagram showing the crystal structure of a compound having a titanium phosphide type structure.

FIG. 10 is a schematic diagram showing the crystal structure of a compound having a tungsten carbide type structure.

FIG. 11 is a diagram showing the state of the interface between the Pt layer and the underlayer when the surface of the underlayer is significantly different from the plane viewed from the [111] direction of Pt.

FIG. 12 is a diagram showing the state of the interface between the Pt layer and the underlayer when the surface of the underlayer is similar to the surface of Pt viewed from the [111] direction.

FIG. 13 shows a magneto-optical recording medium with a Pt/Co stacked structure according to the present invention (using AlN as the underlayer) and a magneto-optical recording medium with a Pt/Co stacked structure according to the prior art (Si3N
4 is used as the base layer).

[Explanation of symbols]

1 Substrate 2 Underlayer 3 Pt/Co laminated film 4 Underlayer (Si3N4) 5 Etching 6 Underlayer (GaAs) 7 Pt atoms 8 Underlayer atoms 9 Magneto-optical recording medium with Pt/Co laminated structure according to the present invention (AlN (used as base layer)

Claims (1)

[Claims] Claim 1: A magneto-optical recording medium having a structure in which a Pt layer is formed on the substrate side of a recording film, which has a cen-enite structure, a wurtzite structure, a nickel arsenide structure, a titanium phosphide structure, and a tungsten carbide structure. A magneto-optical recording medium characterized in that a transparent compound having one of the following structures is sandwiched between the substrate and the Pt layer as an underlayer.