JPS60151225A - 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, Al, Zn and Fe. CONSTITUTION:A prescribed amount of BaCO3 or SrCO3 is mixed with prescribed amounts of Fe2O3, Al2O3 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 gold-Re compound magnetic material and a magnetic film made of the same.

BACKGROUND OF THE INVENTION In recent years, magneto-optical recording media in which magnetic recording is performed 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. A magnetic film is formed by depositing the magnetic material to a thickness of about .1 to 1 μm. Recording and reproduction of the magneto-optical recording medium l\ thus obtained is performed as follows. That is, recording is performed by heating the magnetic film by irradiating laser light modulated with a binary signal to change the direction of magnetization, taking advantage of the property of rapid changes in coercive force corresponding to temperature changes near the Curie temperature or compensation temperature of the magnetic film. This is done by reversing the . Further, reproduction is performed by reading out using the difference in the magneto-optical effect of the magnetic film recorded in this way. Magneto-optical recording media using the above-mentioned amorphous alloy magnetic material can be easily produced by vacuum evaporation or sputtering, and have a Curie temperature of 70 to 70°C.
Although it has the advantage of being able to record at high speeds (at a frequency of IMHz) using semiconductor laser light due to the relatively low temperature of 200°C and high recording sensitivity, amorphous alloy magnetic materials, especially transition metal components, are susceptible to oxidative corrosion. This has the major disadvantage that the magneto-optical properties of the magnetic film deteriorate over time. To prevent this, Si
Provide a protective film such as O, SiO, etc. (formation method is the same as for magnetic films, such as vacuum evaporation, sputtering, etc.)
It is also known that when forming a magnetic film or protective film,
O2 remaining in the vacuum, O7 adsorbed on the substrate surface. H,
O, etc. and 0□, H contained in the alloy magnetic target
, 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. Furthermore, as a reproduction method to improve the reproduction output, the magnetic film is made as thick as possible, and secondly, Cu, AQ, Pt+
The reflective Farade type method, in which a reflective film such as Au is provided, a laser beam is irradiated and transmitted through the magnetic film, and then reflected by the reflective film and the reflected light is detected, has the advantage that a high S/N signal can be obtained. Although advantageous, conventional amorphous magnetic films cannot be used in this method due to their lack of light transmission.

Purpose The purpose of the present invention is to provide a novel metal oxide magnetic material that 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 a novel metal oxide magnetic material that is particularly suitable as a material for magneto-optical recording media. The purpose of the present invention is to provide a magnetic film having the following properties.

Structure The metal oxide magnetic material of the present invention is represented by the general formula (1) (% formula %), and the magnetic film is made of the metal oxide magnetic material of the general formula.

The magnetic material or magnetic film used in magneto-optical recording media has magneto-optical properties (
In particular, in order to obtain high recording sensitivity, the Curie temperature Tc must be low, and in order to maintain the recorded memory stably, the coercive force must be 1. -10 is required to be moderately high. Generally, the appropriate range of this TC and t1c is T
It is assumed that r is 100 to 400°C and Hc is 300 to 6000 oersted. This is because when Tc is below 100°C, the recorded memory becomes unstable due to laser light during playback, causing deterioration of playback characteristics, and when Tc is above 400°C, recording with semiconductor laser light is difficult. ) If 1c is less than 300 oersteds, the memory may become unstable and disappear, and if it is more than 6000 oersteds, the laser output and external magnetic field necessary for magnetization reversal during recording will become large, which may cause some problems. be. 10 for saturation magnetization
00 Gauss or more is required, and below this value the reproduction output is too small to 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, 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 focused on the fact 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 IOμ. However, since the Curie temperature Tc of these materials is as high as 450° C. or higher, 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. Therefore, the present inventors conducted various tests and found that some of the Fe atoms in general formula (2) were replaced by A O, or Z
It has been found that when substituted with an n atom, Tc decreases in both cases of AQ substitution and Zn substitution. At the same time, it was found that the coercive force increases in the case of AQ substitution, but decreases in the case of Zn substitution. Furthermore, it has been found that saturation magnetization hardly changes when Zn is used, but it decreases when AQfil is used. For example, A O, or Z
n-substituted BaFe, 2-2M7. O.

(M represents AQ or Zn, Z represents the number of substitutions of AQ or 7.n) shows a tendency as shown in Figure 1 for Tc, and a tendency as shown in Figure 2 for Hc, and further Regarding Ms, the tendency was shown in Figure 3. Therefore, the present inventors focused on the substitution effect of AQ and Zn, and further considered the appropriate ranges of rc, Hr, and Ms required for the magnetic material or magnetic film for magneto-optical recording media. As a result of replacing a part of Fe in general formula (2) with two types of metals, 80 and 1, in various proportions, the metal oxide magnetic material of general formula (1) has excellent properties as a magneto-optical recording medium. The present invention has been achieved based on the discovery that the following can be achieved.

As described above, the present invention has a particularly high Curie temperature, so it can be used as a material for magneto-optical recording media.
Some of the Fe atoms in the metal compound of 2) are replaced with AQ and 7.
By substituting n atoms, the Curie temperature can be lowered while maintaining the moderately high coercive force and saturation magnetization required for memory, making recording and reproducing using semiconductor laser light possible1, thus creating a magneto-optical recording medium. This material can be used as a material for industrial use.

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, B aAQX'Zny' Fe12- t x
' , * y ' + o+q (where X' is the number of AQ substitutions and Y' is the number of Zn substitutions), Tc is, as shown in Figure 4, when the number of AQ substitutions X' is 2.05 and the Zn substitution Number Y
When ' is 2.5, the temperature is 218°C, and as shown in Fig. 5, Hc is 218°C when the number of substitutions
When the number of substitutions Y' is 2.5, the Oersted is approximately 3.9. Furthermore, Ms is the number of substitutions X of AQ, as shown in Figure 6.
' is 2.05, and when the number of Zn substitutions Y' is 2.5, it is about 3150 Gauss (as 4πMs). Due to these Tc, Hc, and Ms characteristics, the metal oxide magnetic material or magnetic film of the present invention can be applied as a material for magneto-optical recording media that is recorded and reproduced by semiconductor laser light. It has features such as high sensitivity, oxidation corrosion resistance, and translucency.

To make the metal oxide magnetic material of the present invention, a predetermined amount of Ba is required.
C0, or 5rCO, and Fe2O.

ΔQ, 03 and ZnO are mixed and pulverized, the pulverized material is placed in a mold of an appropriate shape, molded, and then sintered at a temperature of 1200 to 1400°C.

A specific example of the metal oxide magnetic material of the present invention obtained as described above is Ba0.5.2 (AQ Zn Fe 03).

Ba0.5.4 (AQ Zn Fe O,).

#l　a,g　1I Ba0.5.4 (AQ Zn Fe O,).

-U -U /,? B a 0 ・5.6 (ΔQ,, Z n,,, F
e,FO,).

BaO'5.6 (AQ,,Zn,,Fe,,01)
+B a 0 ・5.6 (A Q, , Z n,,
, F e,,03).

Ba0・5.8 (AQ, , Zn, , Fe, , Ol)
.

Sr0 ・5.2 (AQ Zn Fe O,l)
.

S rO・5.6 (AQ, 3Zn, , Fe, 302
) +S'r0 ・5.8 (AQ Zn Fe O
,).

al #7ta/! etc.

Furthermore, in order to further increase the Faraday rotation angle and improve the magneto-optical properties of the metal oxide magnetic material described above, Cot is used.
Bit V+ La+ Y+ Yb+S1η, Tb,
Metals such as Dy and 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, generally this magnetic material is deposited on the substrate as a target layer 1 to a film thickness of about 0.1 to 10 μm using a method such as vacuum evaporation, sputtering, or ion blasting at a substrate temperature of 500 to 600°C. That's fine. In this way, as shown in FIG. 7, 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, 500
It is necessary to perform perpendicular magnetization by heat treatment at ~700° C. while applying a magnetic field if necessary. Here, the substrate material is generally a heat-resistant metal such as Aluminum 12;
Quartz glass; G G c ; Sapphire; Lithium tantalate; Crystallized transparent glass; Pyrex glass;
Single crystal silicon with or without surface oxidation treatment; A9
．． O7,Ao,,o,・M g O.

M g O−L i F + Y 203 ・L i
F + B e O.

Transparent ceramic materials such as ZrO, ・Y, O7, The, ・CaO, etc.; inorganic materials such as inorganic silicon materials (for example, Toshin Silicon Co., Ltd.'s Tosugat, Sumitomo Chemical Co., Ltd.'s Sumicelam P), or acrylic resins, polycarbonate resins, polyester resins, etc. Organic materials 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 1 - a substrate with a rack, 3 is a reflective film, 4 is a transparent dielectric layer, 5 is a guide trunk layer, 6 is a protective film, 7 is a transparent adhesive layer, and 8 is a heat-resistant layer. Here, the guide trunk (=J) substrate 1' is formed by injection molding, extrusion molding, or
It is made by processing using photo-etching methods, etc. Note that the guide track on the substrate guides the laser beam during recording and reproduction. Reflective film 3C+i, AIJ+Ag+
ΔIJ.

P t , 1' e Ox + T e C, S e
A s + T e A s + TiN, ]'aN
, CrN, cyanine dye, phthalocyanine dye, etc. are deposited on the target surface by vacuum deposition, sputtering, ion printing, etc. to a thickness of about 500 to 10,000 layers. 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 7 and passing through the magnetic film again. The transparent dielectric layer 4 is S i C12+ S + O.

T iO21T i O+ Ce O+ Hf O2−
B e O.

]'hO2+ S L N, etc. is deposited on the target surface in the same manner as described above to a film thickness of about 0.05 to 0.5 μm. 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 pressing a mold having a guide groove thereon.
It is formed by curing the resin by irradiating it with ultraviolet rays. The protective film 6 is made of acrylic resin, polyurethane resin,
Polycarbonate resin, polyether sulfone resin, polyamide resin, epoxy resin, T i N + S i
N + T a N + Si O2, Si C1
etc., in the case of resin, by coating method, in other cases, vacuum evaporation,
It is formed by depositing a film of 0.1 to 10 .mu.m in thickness on the target surface at a time, using a method such as sputtering or ion blasting. Note that this protective film is provided for the purpose of protecting the reflective film 3. The transparent adhesive layer 7 is made of a heat-resistant film 18 (this layer is made of the above-mentioned inorganic material, so the transparent adhesive layer 7 is made of the inorganic material described above, "Heat-resistant layer provided with a film" refers to the single-layer type magneto-optical recording material.
Approximately 2 to 1.00μ with resins such as polyurethane and polyamide
■It is formed by adhering it to a certain thickness. That is, this transparent adhesive layer is simply a layer for bonding the reflective film 3 of the substrate vinyl and the magnetic film 2 of the single-layer type magneto-optical recording material. The heat-resistant layer 8 is made of the above-mentioned inorganic material and corresponds to the substrate 1, but is provided here for the purpose of improving the heat resistance of the magnetic film 2. The 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 carried out by irradiating modulated or deflected laser light from the magnetic film or substrate side, as in the prior art.

Effect The metal oxide magnetic material or magnetic film of the present invention has appropriate Tc, He, and Ms as a material for magneto-optical recording media, and although it has high recording sensitivity, it has oxidation and corrosion resistance that conventional products did not have. Since the magneto-optical properties do not deteriorate over time, and transmitted light can also be used during reproduction, it is possible to perform reproduction using the Faraday rotation angle with high reproduction output9. An example of the invention is shown.

Examples 1 to 1O Using each target having the composition shown in the table below, an Ar partial pressure of 2.0 nwn T was applied to a quartz substrate whose surface had been optically polished.
, o r r, 02 partial pressure 0.3 + nmT o r r
A magnetic film having a thickness of 0.3 μm was formed by sputtering for 2 hours at a discharge force of 0.35 KV and a substrate temperature of 520 to 550° C. The results of measuring the Curie temperature Tc and coercive force Hc 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 10mW and frequency IM at the surface
When recording was performed by irradiating with a pulse of IIz to cause magnetic reversal, recording bits with a bit diameter of about 1.5 μm were formed in each case.

[Brief explanation of drawings]

Figures 1 to 3 show metal oxide magnetic materials Ba Fe,
The number Z of substitutions of AQ or Zn in 2-2M, O, g (M is AQ or Zn, 2 is the number of substitutions of AQ or Zn),
The relationship diagrams of Curie temperature Tc, coercive force Hc, and saturation magnetization Ms, FIGS. 4 to 6, respectively, are for the metal oxide magnetic material BaAQX'Zny' Fe+2-+ X' 4-Y
' + 019 (X' is the number of substitutions of Aρ, Y' is the number of substitutions of Zn) A relationship diagram between the number of substitutions Y' of Zn and Tc, + (c and Ms, Figures 7 to 11 are respectively according to the present invention) 1 is a configuration diagram of an example of a magneto-optical recording medium using a magnetic material or a magnetic film. l... Substrate 1'... Guide 1 - Substrate with rack 2... Magnetic film 3... Reflection Membrane 4...Transparent dielectric layer 5...Guide track layer 6...Protection crotch
7...Transparent adhesive layer 8...Heat-resistant layer 1 figure 2 Atsushi 3 figure 7 bacteria, Figure 6 Figure Y' Clause 10 Procedural amendment written on March 1, 1981, Case indication 1981 Patent application No. 6595 3, Relationship with the person making the amendment Patent applicant Ota, Tokyo Ricoh Co., Ltd., 1-3-6 (674) Nakamagome, Ward - Representative Hama 1) Hiroshi 4, Agent 5, Column 6 of ``Detailed explanation of the invention 1 in the specification subject to amendment'', Inner scope of amendment (1) Correct "transition" in line 4 of page 3 to "1 rare earth". (2) Correct "1μ" on page 6, line 9 to "μm". (31, page 1 O, line 13, “500-600℃” is 1so
o~70 (Corrected to 1℃J. (4) "500~700℃" on line 20 of the same page is 1"50
0-800℃”. (5) Page 11, lines 12-14 [Inorganic materials...
...(omitted) ......Can be used. ] [Inorganic materials can be used. ”. (6) On page 14, line 8, change “deru.” to “deru.-1
Correct to. (7) “Kv” in the 7th line of the 15th member [KWJK, 1”5
50'' is corrected to ['700J. 181 I'ijl 108 lines 1μ'' is corrected to 1μm''. (9) Correct "05" in line 3 of 16th Tei to ['5ooJ. 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