JPS621152A - Photomagnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain a photomagnetic recording medium which increases the Kerr rotating angle and has a good reproduction characteristic by adding at least 1 atom% of Pm, Eu, Ho or Er to a magnetic film consisting of an amor phous rare earth-transition metal. CONSTITUTION:The magnetic film 13 and protective film 15 are laminated on a substrate 11. The film 13 consists of the amorphous alloy film of the rare earth metal-transition metal contg. Pm, Eu, Ho or Er and is formed on the substrate 11 by a sputtering method, vapor deposition method, ion plating method, etc. More preferably, the magnetic film has the compsn. expressed by the formula M1-x(R1-yAy)x, where M is at least one kind of element of Fe and Co, R is at least one kind of element of Sm, Gd, Tb and Dy, A is at least one kind of element of Pm, Eu, Ho and Er, x: 0.1<=x<=0.4 y: 0.02<y<=0.3. The excellent vertical anisotropy and coercive force are thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magneto-optical recording medium used for document files, floppy disks, hard disks, etc.

In recent years, magneto-optical recording media have attracted attention, in which information is recorded by writing magnetic domains on a magnetic thin film using the thermal effect of light, and information is read out using the magneto-optical effect. There is.

Conventionally, the recording layer used in magneto-optical recording media is T.
Thin films made of rare earth-transition metal-based amorphous magnetic materials such as b-Fe alloys are known (Japanese Patent Publication No. 57-20
691), the recording of information on such magneto-optical recording media is carried out by utilizing the rapid change characteristics of the coercive force at the cue, temperature or compensation temperature of the magnetic material.
This is done by irradiating a perpendicularly magnetized magnetic thin film with a laser beam modulated by a value signal, heating it, and reversing the direction of magnetization. Further, reproduction is performed by utilizing the difference in the magneto-optical effect of the magnetic film subjected to inversion recording.

A rare earth-transition metal amorphous magnetic thin film exhibits perpendicular magnetic anisotropy and has a large coercive force Hc, making it suitable for memory materials, but the Kerr rotation angle θk is small at about 0°18°.
There was even more improvement in playback sensitivity.

The present invention provides an optical recording medium using a rare earth-transition metal amorphous magnetic material with excellent magneto-optical properties.

A magneto-optical recording medium of the present invention is a magneto-optical recording medium provided with a rare earth-transition metal based amorphous magnetic film having perpendicular magnetic anisotropy, wherein the magnetic film has a P content of at least IM%.
It is characterized by containing m, Eu, Ho or Er.

The present invention will be explained in more detail below.

FIG. 1 is a cross-sectional view showing an example of the configuration of a magneto-optical recording medium of the present invention, in which a magnetic film 13 and a protective film 15 are laminated on a substrate 11. As shown in FIG. The magnetic film 13 is.

Pm (promethium), Eu (europium), Ho
The substrate 11 is made of an amorphous alloy film of rare earth metals and transition metals containing (holmium) or Er (erbium).
formed on top. Rare earth metals include Sm (samarium), Gd (gadolinium), Tb (terbium), Dy
(dysprosium), and examples of transition metals include Fe (iron) and Go (cobalt). Preferably, the magnetic film has a composition represented by the following general formula (1).

Ml-X(R1-YAY)X (
1) (In the formula, M, R, A, x, and y each represent the following.

M: At least one element among Fe and Go R: Sm
, Gd, Tb, Dy: at least one element A: at least one element among Pm, Eu, Ha, Er;
Seed element x: o, 1≦X≦0.4 y: 0.02<y≦0.3) By setting X and y within the above ranges, excellent perpendicular anisotropy and coercive force can be obtained. The preferred range of the number of substitutions y is 0
．． 05≦y≦0.15.

The appropriate thickness of the magnetic film 13 is approximately 0.03 to 0.5 μm.

The protective film 15 is for preventing the amorphous magnetic material from being oxidized and corroded by oxygen or water.
, Sin, Si, N, , AIN, etc. The protective film is formed by vapor deposition or sputtering.

It can be formed by an ion blating method or the like. The thickness of the protective film is preferably about 0.05 to 1 μm.

A nonmagnetic material is used as the substrate 11, and for example, a transparent substrate or an opaque substrate such as glass, plastic, or ceramic is used.

FIG. 2 shows yet another embodiment of the invention.

Protective films 15 and 17 are provided to sandwich the magnetic film 13, thereby further improving the stability of the magnetic film.

Furthermore, a heat insulating film or a reflective film can be provided on top of the magnetic film.

According to the present invention, the amorphous rare earth-transition metal based magnetic film contains at least 1 atomic % of Pm and Eu.

Kerr rotation angle can be increased by adding Ha or Er.
becomes large, and a magneto-optical recording medium with good reproduction characteristics can be obtained.

Example 1 Using a binary magnetron sputtering device, a Pm chip (IQa+m X 10a+a+X 1 +am")
was placed on a Tb target of 150+amφ, 3 vsrs", and simultaneously sputtered with an alloy target (150+*mφ, 3mm") of Fea, Co, under the following conditions, and sputtered on a rotating substrate. A magnetic film was created. Here, the amount of Pm substitution in the magnetic film was controlled by adjusting the number of Pm chips and substituting a part of Tb with Pm.

The obtained magnetic film was exposed to a He-Ne laser (λ=
633 nm), the Kerr rotation angle θk was determined by the symmetrical angular vibration method, and the relationship between the substitution number y of Pm and θ was investigated.
Shown in the figure.

Meng U's 4th Note - Residual gas pressure: I Xl0 - @TorrAr gas pressure:
5 Xl0-3Torr target material: Fe,...,C
ol1. ,,Tb+Pm discharge electric crab 400W (F e
,,,Cofi, □), 100W (T b + Pm) Sputtering time: 15m1n (film thickness 1000 people) Substrate nickel glass substrate rotation: 30 rpm Example 2 Part of Tb was replaced with Eu to change the magnetic film composition The relationship between the number of Eu substitutions y and the Kerr rotation angle θ is investigated and
Shown in the figure. The conditions for forming the magnetic film were all the same as in Example 1 except for the target.

Target material: F e,,,G o. 0. Tb
+E u Example 3 Part of Tb was replaced with HO to change the magnetic film composition, and the relationship between the number of Ho substitutions y and the Kerr rotation angle θ was investigated.
Shown in the figure. The conditions for forming the magnetic film were all the same as in Example 1 except for the target.

Target material: FelL, Go. ,,, T b
+H.

Example 4 Part of Tb was replaced with Er to change the magnetic film composition, and the relationship between the Er substitution number y and the Kerr rotation angle θ was investigated.
The conditions for producing the six magnetic films shown in the figure are all the same as in Example 1 except for the target.

Target material: F eo, sCONl, T b +
E rFrom Figures 3 to 6, Pm, Eu, Ho or E
By adding r, the Kerr rotation angle is approximately 0.02 to 0.
, 04 degrees, and it can be seen that the reproduction characteristics are improved.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing embodiments of the present invention. FIGS. 3, 4, 5, and 6 are graphs showing the relationship between the number of substitutions y of Pm, Eu, Ho, and Er in the magnetic film and the Kerr rotation angle θ, respectively. 11...Substrate I3...Magnetic film 1
5.17...Protective film agent 3 (Fe0.9COO,l)0.79(Tk)I-yPm
,) H21 middle ny fall 2 Monsagi 4 closing (R10, gco□, 1) 0.7g (Tol-yEuy
) Y procedural amendment in α21 “October 17, 1985 1, Display of the case 1985 Patent Application No. 139770 2, Name of the invention magneto-optical recording medium 3, Person making the amendment Relationship to the case Patent application Ichibancho Phoenix Building, 1-3-6 Nakamagome, Ota-ku, Tokyo Contents of the amendment in column i of the [Detailed Description of the Invention] of the specification (1) On page 4, line 11 of the specification, ry:Q ,02<y≦
0.3'' and Arunwo, fy:o, 02≦y≦0.3Jl
D. Correct. that's all

Claims (1)

[Claims] 1. In a magneto-optical recording medium provided with a rare earth-transition metal-based amorphous magnetic film having perpendicular magnetic anisotropy, the magnetic film contains at least 1 atomic % of Pm, Eu, Ho, or Er.
A magneto-optical recording medium comprising: