JPS60151227A - Magnetic body of metallic oxide and magnetic film - Google Patents

Abstract

PURPOSE:To obtain a magnetic body of a metallic oxide having high recording sensitivity, superior resistance to corrosion by oxidation and a superior light transmitting property by providing a specified sintered composition contg. Ba or Sr, Cr, Zn and Fe. CONSTITUTION:A prescribed amount BaCO3 or SrCO3 is mixed with prescribed amounts of Fe2O3, Cr2O3 and ZnO, and the mixture is ground. The resulting powder is filled into a metallic mold of a proper shape, molded, and sintered at 1,200-1,400 deg.C to obtain a magnetic body of a metallic oxide represented by formula I (where me is Ba or Sr, 0<x<=0.5, 0<y<=0.6, and 5<=n<=6), e.g., a magnetic body of a metallic oxide represented by formula II or III. A magnetic film of 0.1-10mum thickness is formed on a substrate heated to 500-600 deg.C by vacuum deposition, sputtering or other method using the magnetic body as a target.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel metal oxide magnetic material and a magnetic film made of the same.

In recent years, magneto-optical recording media that perform magnetic recording using semiconductor laser light have been researched and developed for high-density recording. Conventionally, magnetic materials used in magneto-optical recording media are often made of amorphous alloys of rare earth metals and transition metals. To make a magneto-optical recording medium using such an amorphous alloy magnetic material, the magnetic material, for example, a Tb-Fe alloy, is generally deposited on a substrate such as a glass plate to a thickness of 0 by vacuum deposition, sputtering, etc. .1 to 111 Tn (J) to form a magnetic film. Recording and reproduction on the 4L magneto-optical recording medium obtained in this way is performed as follows. That is, recording This is done by heating the magnetic film by irradiating it with a laser beam modulated with a binary signal and reversing the direction of magnetization, making use of the characteristics of rapid changes in coercive force in response to temperature changes at one temperature or near the compensation temperature. In addition, reproduction is performed by making use of the difference in the magneto-optical effect of the magnetic film recorded in reverse in this way.The magneto-optical recording medium using the amorphous alloy magnetic material described above has a low recording sensitivity. Because of the high speed, high speed (frequency 1
Although it has the advantage of being able to record with Ml1z),
Since amorphous alloy magnetic materials, particularly transition metal components, are susceptible to oxidative corrosion, there is a major drawback in that the magneto-optical properties of the magnetic film deteriorate over time.

In order to prevent this, the amorphous magnetic film is coated with Sin.

It is also known to provide a protective film such as Sin (using the same method as for the magnetic film, such as vacuum evaporation or sputtering), but when forming the magnetic film or protective film, the 07. O7. adsorbed on the substrate surface. ) I, 0, etc. and 02. l-i,
The magnetic film is oxidized and corroded by O and the like over time, and this oxidative corrosion is further accelerated by light and heat during recording. In addition, amorphous magnetic materials have the disadvantage that they are easily crystallized by heat, which tends to cause deterioration of their magnetic properties.

As a reproduction method to further improve the reproduction output, the magnetic film is made as thick as possible1, and Cu l A Q +
The reflective Faraday type, in which a film is provided with anti-q= such as P t *Δ11, a laser beam is irradiated and transmitted through the magnetic film, and then reflected by a reflective film and the reflected light is detected is a high S/H signal. However, since conventional amorphous magnetic films lack light transmission, they cannot be used in this method.

Purpose The purpose of the present invention is to provide a novel metal oxide magnetic material which has high recording sensitivity, excellent oxidation corrosion resistance and light transmission properties, and is particularly suitable as a material for magneto-optical recording media, and this metal oxide magnetic material. An object of the present invention is to provide a magnetic film made of a magnetic material.

Structure The metal oxide magnetic material of the present invention is represented by the general formula (1) IL.

The magnetic material or magnetic film used in magneto-optical recording media has magneto-optical properties (
In particular, the Curie temperature Tc must be low to obtain high recording sensitivity, and the coercive force Hc must be low to maintain the recorded memory stably. is required to be moderately high. Generally, the appropriate range of Tc and 1-IC is Tc
100-350℃ for C, 300-350℃ for C
It is thought to be 6,000 oerste 1-. This is - “C
If the temperature is below 100°C, the recorded memory becomes unstable due to the laser beam during playback, causing deterioration of the playback characteristics.At temperatures above 350°C, it is difficult to record with semiconductor laser light. If it is less than 300 oersted, the memory may become unstable and disappear, and if it is more than 6000 oersted, the laser output and external magnetic field necessary for magnetization reversal during recording will become large, and IIf will not work. . 1 for saturation magnetization
000 Gauss or more is required, and if it is less than , the reproduction output will be small and it cannot be applied to magnetic recording media.

On the other hand, metal oxide magnetic materials have been studied as magnetic bubble materials. Among these hexagonal crystals, for example, those represented by the general formula (2) (where Me and n are the same as in the general formula (1)) are known. The inventors of the present invention have noted that since this type of magnetic material is itself an oxide, there is no fear of oxidative deterioration and, moreover, it has translucency even with a film thickness of lOμ. However, since the Curie temperature Tc of these materials is as high as 450° (2 or more), recording with semiconductor laser light is difficult as described above, and they cannot be used as is as a material for magneto-optical recording media. Upon investigation, we found that some of the Fe atoms in general formula (2) were replaced with Cr or Z.
It has been found that when substituted with an n atom, Tc decreases in both cases of Cr substitution and Z r+ substitution. at the same time) (c
Although it increases in the case of Cr substitution, Z n rH
It was found that the value decreases in the case of exchange. Furthermore, it has been found that while there is almost no change in Ms in the case of Zn substitution, it decreases in the case of Cr substitution. For example, Cr or Zn [B a F B+2-7. M2O3 (M represents Cr or Zn, Z represents the number of substitutions of Cr or Zn) shows a tendency as shown in Figure 1 for Tc, and a tendency as shown in Figure 2 for He, and 3rd for Ms.
The trend was shown in the figure. Therefore, the present inventors focused on the substitution effect of Cr and Zn, and further improved the Tc, Hc, and M required for magnetic materials or magnetic films for magneto-optical recording media.
As a result of substituting a part of Fe in general formula (2) with two metals, C' and ZTl, in various ratios in consideration of the appropriate range of s, the metal oxide magnetic material of general formula (1) is obtained. It has been discovered that this provides excellent properties as a magneto-optical recording medium, and the present invention has been achieved.

In this way, the present invention solves the problem of the general formula (2
) By substituting some of the Fe J5C atoms in the metal compound of This enables recording and reproduction using semiconductor laser light, thus making it possible to apply it as a material for magneto-optical recording media.

As can be seen from the above description, the metal oxide magnetic material of the present invention satisfies the appropriate Curie temperature range and appropriate coercive force range required as a material for magneto-optical recording media.

For example, BaCrx'Zny'Fe+z-[X'
+ y')019 (where Y' is Cr and Y' is the number of Zn substitutions), Tc is C as shown in Fig. 4.
The number of substitutions X' of r is 2.05, and the number of substitutions Y' of Zn
When is 2.5, the temperature is 218°C, and as shown in FIG. 5, Hc is 218°C when the number of Cr substitutions
When the substitution number Y' of n is 2.5, the Oersted is approximately 3.9.

Furthermore, as shown in Figure 6, Ms has a Cr substitution number X' of 2.
．． 05, and when the number of substitutions Y' of Z n is 2.5,
It is approximately 3150 Gauss (as 4πMs).

These 1. 'c, Hc and Ms characteristics make the metal oxide magnetic material or magnetic film of the present invention i.e.
2 Not only can it be used as a material for magneto-optical recording media for recording and playback, but it also has features such as high recording sensitivity due to its low Curie temperature, oxidation corrosion resistance, and light transmittance. .

In order to make the metal oxide magnetic material of the present invention, a predetermined amount of B is required.
a Co, or 5rCO9 and Fe, O.

and Cr, O, l, and Z n O are mixed and crushed, and this, lt
After molding into a mold of an appropriate shape, 1200 ~ 140
Sintering may be performed at a temperature of 0°C.

Specific examples of the metal oxide magnetic material of the present invention obtained as described above include B a O' 5-2 (Cr Z na, J F
e7. t O1) +B ao '5.2 (Cr,
, Zn, #tFe/, o3).

B110・5.4 (Cr, , Zn, jFe, tOl)
+BaO・5.4 (CrZnFeO3).

a, 3 a, Wr i & B a O' tl , 6 (Cr ,, Z r+
a;r F C/, J○,).

B ao '5.6 (Cr, , Zn, , F
e, 3o3).

s ao ・5- a (c ra, r z na
zt Feyr O3) +B a 0 ・5.8 (
Cr,,, Z I+,,, Fe,, On)
+S ro ・5.4 (Cr, 3Zn, Fe
,, O! l ) +Sr0・5.6(Cr Zn F
eO,).

etc.

In addition, in order to further increase the 11 Faraday rotation angle and improve the magneto-optical properties of the above-mentioned metal oxide magnetic material, Co is added.
o B i+ V+ La, y, 'yb.

Sm+ T'b+ D! /+ Metals such as Gd can be added.

To make a magnetic film using the metal oxide magnetic material of the present invention,
Although it depends on the type of substrate, in general, this magnetic material is deposited on the substrate at a substrate temperature of 500 to 600°C to a film thickness of about 0.1 to 10μI11 by methods such as vacuum evaporation, sputtering, and ion blasting. That's fine. In this way, as shown in FIG. 5, a magneto-optical recording medium having a perpendicularly magnetized magnetic film 2 on a substrate l is obtained. In some cases, the magnetic film may be formed at a substrate temperature of less than 500°C. However, in this case, after forming the magnetic film,
In order to achieve perpendicular magnetization, it is necessary to perform a heat treatment at 500 to 700° C. while applying a magnetic field if necessary. Here, the substrate material is generally a heat-resistant metal such as aluminum; quartz glass: GGO: sapphire; lithium tantalate; crystallized transparent glass; Pyrex glass;
Single crystal silicon with or without surface oxidation treatment; ΔΩ
20s + Aflt O, l'MgO.

MgO・Li F, Y, 0.　’　LiF, Bed.

ZrO,・Y, 02. The (transparent ceramic material such as CaO; inorganic silicon material (for example, Toshin Silicon Co., Ltd. 1-
Inorganic materials such as Sugard and Sumiceram 1) manufactured by Sumitomo Chemical Co., Ltd., or 15% materials such as acrylic resin, polyether-1 resin, and polyester resin can be used.

The magnetic film of the present invention is applicable not only to a single-layer magneto-optical recording medium as shown in FIG. 7, but also to all conventionally known multilayer magneto-optical recording media. Examples of this type of multilayer type include structures shown in FIGS. 8 to 11. In the figure, 1' is a guide track substrate, 3 is a reflective film, 4 is a transparent rA dielectric layer 5 is a guide track layer, 6 is a protective layer, 7 is a transparent adhesive layer, and 8 is a heat-resistant layer. Here guide 1 - rack f'
The substrate is made by processing the above-mentioned organic material by injection molding, extrusion molding, photoetching, or the like. Note that the guide track on the substrate guides the laser beam during recording and reproduction. The reflective film 3 is Cu, AQ, AK, Δu
, Pt.

TeOx, TeC, 5eAs+ TeAs+ TiN
I T a l'J r Cr N + cyanine dye,
Apply phthalocyanine dye, etc. to a film thickness of 500~1 on the target surface by vacuum evaporation, sputtering, ion blasting, etc.
It is formed by attaching it to about 0,000 people. Note that this reflective film is provided for the purpose of increasing the Faraday effect by reflecting the laser light that has passed through the magnetic film and transmitting it through the magnetic film again. The transparent dielectric layer 4 is Sio,
,Sio.

Tie,,Tie,CeO,HfO2,Bed.

Th02. It is formed by depositing Si, N4, etc. on the target surface to a thickness of approximately 0.05 to 0.5 μm using the same method as described above. Note that this transparent dielectric layer is provided for the purpose of increasing the Faraday rotation angle and improving the reproduction output.

The guide track layer 5 is formed by applying an ultraviolet curable resin to the target surface, and then irradiating ultraviolet rays to cure the resin while pressing a mold having guide grooves thereon. The protective film 6 is made of acrylic resin, polyurethane resin, polycarbonate resin, polyether sulfone resin, polyamide resin, epoxy resin, 17 i N + S i 2
N a r T a N , S io , SiO cap is applied to the target surface by a coating method in the case of resin, or by a method such as vacuum evaporation, sputtering, or ion blasting in other cases to a film thickness of about 01L to 10 μnL41 ' It is formed by R. Note that this protective film is provided for the purpose of protecting the reflective film 3.

The transparent adhesive layer 7 is connected to the reflective film of the guide 1 to the substrate provided with the reflective film 3 and the magnetic I+! Heat-resistant layer 8 provided with 42
(Since this layer is made of the above-mentioned inorganic material, the "heat-resistant layer on which the magnetic film is installed" refers to the above-mentioned single-layer magneto-optical recording material.) The magnetic film is made of epoxy resin, polyurethane,
It is formed by contacting with a resin such as polyamide to a thickness of about 2 to 100 μm. That is, this transparent adhesive layer simply connects the reflective film 3 on the substrate 1' and the magnetic film 2 of the single-layer magneto-optical recording material.
This is a layer for joining. Note that the heat-resistant layer 8 is made of the above-mentioned inorganic material and thus corresponds to the substrate 1, but here it is provided for the purpose of providing heat resistance of the magnetic layer 1 and 2. Appropriate thickness is approximately 10 to 500 μm.

Recording and reproduction on the above-described magneto-optical recording medium using the magnetic film of the present invention is performed by irradiating modulated or deflected laser light from the magnetic film or substrate side, as in the conventional method. Although the fully bent oxide magnetic material or magnetic film of the invention has appropriate TC+Hc and Ms as a material for magneto-optical recording media and has high recording sensitivity, it has oxidation corrosion resistance and transparency that conventional products did not have. Since the magneto-optical characteristics do not deteriorate over time, transmitted light can also be used during reproduction, and therefore reproduction can be performed using a Faraday rotation angle with a high reproduction output.

Examples of the present invention are shown below.

Examples 1 to 10 Using each target having the composition shown in the table below, Ar partial pressure of 2.0. OWI+T
o r r , O, partial pressure 0.3 + nm-r o r
r, discharge power 0.35KV, substrate temperature 520-550℃
Sputtering was performed for 2 hours under the following conditions to form a magnetic film with a thickness of 0.2 μm. The results of determining the Curie temperature 1°c and coercive force tic of these magnetic films are shown in the table below.

Next, each magneto-optical recording medium obtained as described above is magnetized in one direction, and a semiconductor laser beam with an output of 20 mW is applied to the recording medium while applying a magnetic field of 0.5 oersted opposite to the direction of magnetization. Intensity 10+nv and frequency I at the surface
When irradiation with a pulse of Mllz was performed to cause magnetic reversal and recording, recording pits 1 to 1 with a diameter of about 1.5 .mu.+ were formed.

[Brief explanation of drawings]

Figures 1 to 3 show metal oxide magnetic materials B a Fe
, 2-z Mz Oxg (M is Cr or Zn, Z
is the number of substitutions Z of Cr or Zn), the Curie temperature Tc, the coercive force He, and the saturation magnetization M
s and FIGS. 4 to 6 respectively show the relationship between metal oxide magnetic material BaC: rx'ZnV'Fan-(X'+y'
+019 (X' is the number of substitutions of Cr, Y' is the number of substitutions of Zn), (the number of substitutions Y' of Z n, Tc, Hc and M
s and FIGS. 7 to 11 are configuration diagrams of an example of a magneto-optical recording medium using the magnetic material or magnetic film of the present invention, respectively. l...Substrate 1'...Substrate with guide track layer 1 2...Magnetic film 3...Reflection film 4...Transparent dielectric layer 5...Guide track layer 6...
Protective film 7...Transparent adhesive layer 8...Heat-resistant layer Figure 6 Y' Award Figure 10 - March 13, 1980 Pe. - Representative Hama 1) Hiro 4, Agent 5, W stone 6 of "Detailed description of the invention" of the specification subject to amendment, ■Correct contents (1) One line from 2nd onwards [Transition 81] 1゛ Corrected to rare earthenware 1. (2) Correct "Fμ" on page 6, line 3 to 1 μmj. (3) Line 1006 “500~600°Cj”5
00 to 700°C. (4) Line 13 of the same page, i
50 (Correct 1 to s o o ” c j. (5) Page 11, lines 5 to 7 [Inorganic materials...
・(omitted)－・・・・・・Can be used. " is corrected to "Inorganic materials can be used." (6) The 14th member “is” on the first line is 1. ”. (7) Line l”4vj from the bottom of the same page [KWjK, 1'
-55oJ is corrected to "700". (8) Correct "μ" in line 1 of page 15 to 1 μm. (91 5 lines from the bottom of the same page [0,5J] [' 500 j
Correct to. that's all

Claims (1)

[Claims] 1. General formula %formula%) ) A metal oxide magnetic material represented by . 2. General formula %formula%) ) A magnetic film made of a metal oxide magnetic material represented by