JP3108126B2 - 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 magneto-optical recording medium having a structure in which a layer is formed.

[0002]

2. Description of the Related Art FIGS. 2 and 3 show an example of a conventional magneto-optical recording medium having a Pt / Co laminated structure. FIG. 2 shows that an underlayer (Si ₃ N ₄ ) 4 is formed on a glass or PC (polycarbonate) substrate 1 in order to increase the Kerr effect, and the surface of the formed underlayer 4 is smoothed. Etching 5 treatment is performed, and Pt and Co are further deposited on the Pt layer, the Co layer,
…, Pt layers in this order (14th Annual Meeting of the Japan Society of Applied Magnetics (1990), p. 65, “Pt
/ Co microstructure of laminated film ”, Sumi et al.). In such a magneto-optical recording medium, the Si ₃ N ₄ is amorphous, and the Pt layer is not stacked clearly in the [111] direction. Therefore, the perpendicular magnetic anisotropy is small and the coercive force is only about 1 kOe.

[0003], GaAs6 or Ag, as shown in FIG. 3
It has been reported that the coercive force of a magneto-optical recording medium having a Pt / Co laminated structure was increased to 4 kOe by using as an underlayer (E-MRS spring '90).
CVIII-7), GaAs6 and Ag are opaque, so if such an underlayer is provided, signals cannot be read.

[0004]

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

[0005]

SUMMARY OF THE INVENTION In a magneto-optical recording medium in which a recording film is composed of an alternately laminated film composed of a Pt layer and a transition metal layer, or a magnetic layer composed of a Pt layer and a rare earth transition metal alloy layer, a senaene mineral type is used. Structure, wurtzite type structure, nickel arsenide type structure, titanium phosphide type structure, an underlayer made of a transparent compound having any one of the tungsten carbide type structure, an alternately laminated film, or a magnetic layer, The structure was inserted between the substrate and the Pt layer so that the Pt layer was in contact with the underlayer.

[0006]

In the magneto-optical recording medium according to the present invention, the Pt layer constituting the recording film is in contact with the underlayer having a crystalline structure. Crystals are densely arranged in the same manner as a base layer in which crystals are densely arranged. As a result, the coercive force of the recording film increases, and high-density recording becomes possible.

[0007]

An embodiment according to the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view 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 formed on the base layer 2. layer,
.., The Pt / Co laminated film 3 is formed in the order of the Pt layer. For the underlayer 2, 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 was used.

The Pt crystal is a face-centered cubic lattice as shown in FIG. 4, and has a structure in which the Pt crystals are densely stacked as shown in FIG. 5 when viewed from the [111] direction. The lattice constant is 3.9 ° and the interatomic distance is 2.8 °. When 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 is improved.

FIGS. 6 to 10 show a case where a plane having a crystal is arranged in the same manner as a plane viewed from the [111] direction of Pt. FIG. 6 shows a cubic senaenite type structure, which is densely arranged like Pt when viewed from the [111] direction. 7 is a wurtzite structure, FIG. 8 is a nickel arsenide structure, FIG. 9 is a titanium phosphide structure, and FIG. 10 is a tungsten carbide structure, all of which are hexagonal and viewed from the [111] direction. Pt
In the same dense arrangement as the plane viewed from the [111] direction. Therefore, a substrate having the above crystal structure and having a cubic lattice constant of around 3.9 ° and a hexagonal lattice constant of around 2.8 ° is used as an underlayer. Is also formed with the closest structure. FIG.
FIG. 12 shows the case where the surface of the underlayer is significantly different from the surface of the Pt viewed from the [111] direction.
3 shows a state of an interface between a layer and an underlayer. here,
7 is a Pt atom, and 8 is an atom of the underlayer. FIG. 12 shows Pt
Are formed in the closest arrangement.

Table 1 shows examples of compounds used for 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 having a Pt / Co laminated structure using AlN as an underlayer and a magneto-optical recording medium having a Pt / Co laminated structure (Si ₃ N ₄₎ according to the prior art. FIG. 10 is a characteristic diagram of No. 10 in which is used as an underlayer. FIG. 13 clearly shows that the coercive force of the magneto-optical recording medium having the Pt / Co laminated structure according to the present invention is increased.

Similar effects can 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 (eg, Fe) and Pt, or a structure in which a Pt layer is formed on the substrate side of a magnetic film (eg, a rare earth-transition metal alloy). It may be.

[0016]

According to the present invention, Pt is added to 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. as a result,
High density recording becomes possible.

[Brief description of the drawings]

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

FIG. 2 is a sectional structural view of a magneto-optical recording medium having a Pt / Co laminated structure using Si ₃ N ₄ as an underlayer.

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

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

FIG. 5 is a view showing the Pt crystal of FIG. 4 viewed from the [111] direction.
It is a figure which shows the mode of a stack of crystals.

FIG. 6 is a schematic view showing a crystal structure of a compound having a senaenite structure.

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

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

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

FIG. 10 is a schematic view showing a 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 surface of the Pt viewed from the [111] direction.

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

FIG. 13 shows a Pt / Co laminated magneto-optical recording medium (using AlN as an underlayer) according to the present invention and a conventional Pt / Co laminated magneto-optical recording medium (Si ₃ N _4).
FIG. 4 is a characteristic diagram of a case where the underlayer is used as a base layer).

[Explanation of symbols]

1 substrate 2 underlayer 3 Pt / Co multilayer film 4 underlayer (Si ₃ N ₄₎ 5 etched 6 underlayer (GaAs) 7 magneto-optical recording medium of the Pt / Co multilayer structure according atoms nine invention Pt atomic 8 underlayer (using AlN as an underlayer) 10 magneto-optical recording medium of the prior art Pt / Co multilayer structure (Si ₃ N ₄ that using as a base layer)

Claims (1)

(57) [Claims] 1. An alternate lamination comprising a Pt layer and a transition metal layer.
Consisting of a film or a Pt layer and a rare earth transition metal alloy layer
In a magneto-optical recording medium using a magnetic film as a recording film , a transparent structure that is one of a senaenite structure, a wurtzite structure, a nickel arsenide structure, a titanium phosphide structure, and a tungsten carbide structure. A base layer made of a compound , the alternating laminated film, or the magnetic film, and a substrate
A structure in which the Pt layer and the underlayer are in contact with each other;
A magneto-optical recording medium characterized in that: