JPS60180920A - Metallic oxide magnetic body and magnetic film - Google Patents

Abstract

PURPOSE:To obtain the titled magnetic body suitable as the material for a photoelectromagnetic recording medium having high recording sensitivity, excellent resistance to corrosion by oxidation and light transmissive property by constituting the body of Ba, Sr, Ga, Sc, Ti, Sn, Zn, Fe, and O shown by a specified gneral formula. CONSTITUTION:The metallic oxide magnetic body consists of a compd. shown by the general formula BaxSr1-xO.(Gay.MezFe2-y-m/3z)O3 [where Me is >=1 kind of element among Sc, Ti, Sn, and Zn, (m) is the number of the valances of the iron, and 5.0<=n<=6.0, 0<x<1, 0<y<=0.8, and 0<z<=0.8]. The magnetic body has the Curie temp. Tc and the coersive force Hc within an appropriate range necessary for obtaining high recording sensitivity, and hence has less extent of deterioration of the magnetic characteristic with time. Said magnetic body is obtained by mixing and crushing a specified amt. of BaCO3, SrCO3, Fe2O3, and Ga2O3 and >=1 kind among Sc2O3, TiO2, SnO2, and ZnO, molding the mixture in a metallic mold, and then sintering the molded body at about 1,200-1,400 deg.C.

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 is generally placed on a substrate such as a glass plate.
For example, a Tb-Fe alloy is deposited to a thickness of about 0.1 to 1 μm by vacuum evaporation, sputtering, etc. to form a magnetic film. In other words, recording is performed by using the characteristic of the magnetic film's rapid change in coercive force corresponding to temperature changes near the Curie temperature or the compensation temperature to direct a laser beam modulated in binary 4B to the magnetic film. This is done by inverting the direction of magnetization by irradiating the magnetic film with high intensity. Also, reproduction is performed by using the difference in the magneto-optical effect of the magnetic film recorded in this way. Magneto-optical recording media using high quality alloy magnetic materials have high recording sensitivity, so they can be recorded at high speeds (frequency IMll) by semiconductor laser light.
Although it has the advantage of being able to record at 300° C.), it has the major drawback that the magneto-optical properties of the magnetic film deteriorate over time because amorphous alloy magnetic materials, especially rare earth metal components, are susceptible to oxidative corrosion. In order to prevent this, it is known that a protective film such as SiO, SiO□, etc. is provided on the amorphous magnetic film (the formation method is by vacuum evaporation, sputtering, etc., as in the case of the magnetic film). When forming a magnetic film or protective film, O2 remains in vacuum, O adsorbed on the substrate surface,
0□ contained in targets of 820 etc. and alloy magnetic materials
, H2O, etc. over time, and this oxidative corrosion is further accelerated by light and heat during recording. In addition, amorphous magnetic materials are easily crystallized by heat,
Therefore, it has the disadvantage that magnetic properties tend to deteriorate. Furthermore, as a reproduction method to improve reproduction output, the magnetic film is made as thick as possible, and 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.

1-Part of the metal oxide magnetic material of the present invention has the general formula (1) % formula %) (However, Me represents at least one element selected from Sc, Ti, Sn, and Zn, and Il represents an ion of Me. Indicates the valence, n, x+y+Z are each 5.0≦n≦6.0゜0<
x≦1.0. It represents a value of O<z≦0.8. ), and the magnetic film is made of a metal oxide magnetic material having the above general formula.

The magnetic material or magnetic film used in magneto-optical recording media must have magneto-optical properties (appropriate Curie temperature, coercive force, etc.) that allow recording and reproduction using semiconductor laser light. In order to obtain sensitivity, it is necessary that the Curie temperature Tc be low, and in order to maintain the recorded memory stably, it is necessary that the coercive force He be appropriately high.

Generally, the appropriate range for Tc and He is 1 for Tc.
00 to 350°C, and 300 to 6000 oersted for He. 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;
Above this, it is difficult to record with a semiconductor laser beam.On the other hand, if He is less than 300 Oersteds, the memo JJ- may become unstable and disappear, and if it is more than 6000 Oersteds, it is difficult to record with a semiconductor laser beam. This is because the laser output and external magnetic field become large, which is undesirable.

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) % formula %] (where n is the same as in 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 that it has light transmittance even with a film thickness of 10t1n+. 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 materials for magneto-optical recording media.

Therefore, the present inventors conducted various studies based on the magnetic material of general formula (2). As a result, it has been found that Tc can be lowered by substituting some of the Fe atoms in general formula (2) with Ga, Sc, T%, Sn, and Zn atoms. At the same time, regarding He, Gal! In the case of exchange, it increases, but S
It was found that c + T decreased in the case of 1rSn and Zn substitutions. Furthermore, when a part of Ba is replaced with Sr, the effect of replacing Ga, Sc, etc. is the same, but the residual magnetization can be increased. For example, B a, , S r, , F e ,2- x,'
M, 'O,.

(M represents Ga, Sc, Ti, Sn and Zn,
8' indicates the number of substitutions of M. ), when each of the above atoms is substituted, Tc is shown in Figures 1-1 to 1-4.
The trend was shown in the figure. Regarding He, Section 2-1
The trends shown in Figures 2-4 were shown. In addition, here G
To clearly distinguish between aM substitution and other atomic substitutions, Ga! is shown in all figures. The results of the conversion are illustrated.

Therefore, the present inventors investigated such Ga or Sc.

Focusing on the substitution effects of Ti, Sn, and Zn, we also focused on the Tc and Hc 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 a combination of Ga and one of the other four types of atoms in various proportions in consideration of the above-mentioned appropriate range of general formula (1), The inventors have discovered that metal oxide magnetic materials provide excellent properties as a magneto-optical recording medium, and have arrived at the present invention.

In this way, the present invention solves the problem of the general formula (2
) by substituting some of the Fe atoms in the metal oxides with Ga and one of the other four atoms mentioned above, the Curi Recording by semiconductor laser light by reducing the
This material enables reproduction and can be applied as a material for magneto-optical recording media.

For example, Ba,,,ISt',,tGay' Mez
'Fe12-v'-z' 019 (However, M
e represents an element selected from Sc, Ti, Sn and Zn; 1. ' represents the number of Ga substitutions, and 2' represents the number of Me substitutions. )
When the influence on Tc and He was investigated by varying the number of substituted atoms, the results shown in FIGS. 3 and 4 were obtained.

Here, when M e = S c: Fig. 3-1 and Fig. 4-1. When Me = Ti: Fig. 3-2 and Fig. 4-2 M e
= S n case ゛: Figure 3-3 and Figure 4-3 M'e
=Zn: Figures 3-4 and 4-4. Further, to explain the case of MezSc as an example, the number of substitutions of Ga, ′
When is 2.24 and the number of In substitutions is 1.2, Tc is 225 DEG C. from FIG. 3-1, and 11c is 4200e from FIG. 4-1. Me is Sc, Ti, Sn and Zn
A similar trend was observed in the case of Due to these Tc and Hc properties, the metal oxide magnetic material or magnetic film of the present invention can be applied as a material for magneto-optical recording media that performs recording and reproduction using semiconductor laser light. In addition to being expensive, it has features such as oxidation corrosion resistance and translucency.

In order to make the metal oxide magnetic material of the present invention, a predetermined amount of B is required.
aCOs and 5rCO, and Fe, O, and Ga, O, and further Sct O@ , TiO2, S rt C) a + Zn
Any one of O can be mixed and pulverized, put into a mold of an appropriate shape, molded, and then sintered at a temperature of 1200 to 1400°C.

Specific examples of the metal oxide magnetic material of the present invention obtained as described above include Ba, #5ra3t016 (G aa, Yu7 S
ca, ta F e /l O++ ) B a o,
7t S r, J) O°6 (G a,, a7 Z n
a,ttFel,sO@)Sr+QtBaa,
wO16(G a a4 T j 6.sl F et
, 910 m) Ba, , Sr, 0.6 (G
a,,,,S n,,7. F e2. rO*).

In order to further increase the Faraday rotation angle and improve the magneto-optical properties of the metal oxide magnetic materials described above, Gon is added.
Bit V+ La, Y, Yb.

Metals such as Sm, "rb, Dy+Gd, etc. 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 vacuum evaporated onto the substrate at a substrate temperature of 500 to 700°C.
The film may be deposited to a thickness of about 0.1 to 10 μm using methods such as sputtering and ion blasting. In this way, as shown in FIG. 5, a perpendicularly magnetized magnetic film 2 is placed on the substrate 1.
A magneto-optical recording medium having the following properties 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~
Heat treatment at 800°C, while applying a magnetic field if necessary.
It is necessary to perform perpendicular magnetization. Here, the substrate materials are generally heat-resistant metals such as aluminum; quartz glass; GGG; sapphire; lithium tantalate; crystallized transparent glass; Pyrex glass; Vycor glass; AQ2011゜AQ, O,・M g Or M
g O-L i F e Y 209・L i F H
B e OHZ r O2・Y 20s T T ho
2. A transparent ceramic material such as CaO; an inorganic material such as an inorganic silicon material (for example, Tosguard manufactured by Toshiba Silicon Co., Ltd. or Sumiceram P manufactured by Sumitomo Chemical Co., Ltd.) 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. 5, but also to all conventionally known multilayer magneto-optical recording media. Examples of this type of multilayer type include structures shown in FIGS. 6 to 9. In the figure, 1' is a substrate with a guide track, 3 is a reflective film, 4 is a transparent dielectric layer, and 5 is a substrate with a guide track.
is a guide track layer, 6 is a protective film, 7 is a transparent adhesive layer, 8
is a heat-resistant layer. Here, the guide track-equipped substrate 1' is manufactured 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, AQT Ag, Au+Pt*
TeOx, TeC, 5eAs, TeAs.

It is formed by depositing TiN, TaN, CrN, cyanine dye, phthalocyanine dye, etc. on the target surface to a thickness of about 500 to 10,000 layers using methods such as vacuum evaporation, sputtering, and ion blasting. 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 made of Sin.

Tie,,Tie,Ce,0. HfO,,Bed.

The2. It is formed by depositing St, IN, etc. on the target surface to a film thickness of about 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, polyethersulfone resin, polyamide resin, epoxy resin, T i N t S ] 9
N 4 pT a N + -3i O2* S +
In the case of resin, it is formed by a coating method, and in other cases, it is formed by adhering it to the target surface by a method such as vacuum evaporation, sputtering, ion blating, etc. to a film thickness of about 0.1 to 1 μm. Note that this protective film is provided for the purpose of protecting the reflective film 3.

The transparent adhesive layer 7 consists of the reflective film of the substrate 1' with guide tracks provided with the reflective film 3 and the heat-resistant layer 8 provided with the magnetic film 2 (this layer is made of the above-mentioned inorganic material, so the "heat-resistant layer provided with the magnetic film") '' refers to the single-layer type magneto-optical recording material.) It is formed by adhering the magnetic film of 2 to 100 μm thick with a resin such as epoxy resin, polyurethane, or polyamide. That is, this transparent adhesive layer is simply a layer for bonding the reflective film 3 on the substrate 1' and the magnetic film 2 of the single-layer magneto-optical recording material. Note that the heat-resistant layer 8 is made of the above-mentioned inorganic material and thus 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 about 10~500mm
Approximately μm is appropriate.

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.

The metal oxide magnetic material or magnetic film of the present invention has Tc and Ic suitable for use as a material for a magneto-optical recording medium, Tc and He suitable for use as a material for a recording medium, and has high recording sensitivity. Despite this, it has oxidation corrosion resistance and transparency that conventional products did not have, so there is no deterioration of magneto-optical properties over time.
In addition, 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 4 Using each of the targets having the compositions shown in the table below, a reflective layer of Ag with a thickness of 500 layers was deposited on a quartz substrate by vapor deposition, and a layer of 5 in 2 with a thickness of 100 layers was deposited on this substrate by sputtering.
0 people covered and Ar partial pressure 2.0'++n Tor
r, 02 partial pressure 0.3m T o r r, discharge force 0
．． A magnetic film with a thickness of 0.3 .mu.m was formed by sputtering for 2 hours at 35 kW and a substrate temperature of 520 to 700.degree.

The results of measuring the Curie temperature Tc and coercive force He 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 while applying a magnetic field of 500 oersted opposite to the direction of magnetization, a semiconductor laser beam with an output of 2 ν is applied to the recording medium. Intensity 10 mV and frequency I M at the surface
When recording was performed by irradiating with a pulse of II z to cause magnetic reversal, recording bits with a bit diameter of about 1.5 .mu.m were formed in each case.

[Brief explanation of the drawing]

FIGS. 1 and 2 respectively show −metal oxide magnetic material Bai+
,7#"r,,atFelp-X'MX'Ol
FIG. 3 is a diagram showing the relationship between the number of substitutions 8' in g (M indicates Ga + S-c, Ti, Sn, and Zn, and +X' indicates the number of substitutions of M), the Curie temperature Tc, and the coercive force Hc. 3 and 4 respectively show metal oxide magnetic materials Baa,
Sr,,,yGay'Me2'FeI2-y
' -z ' 0+s (Me represents an element selected from S'c, Ti, Sn and Zn; 1.' represents the number of substitutions for Qa, 2
' indicates the number of Me substitutions. ) and the replacement numbers t′ and 2
', Tc and He. 5 to 9 are configuration diagrams of examples of magneto-optical recording media using the magnetic material or magnetic film of the present invention, respectively. l...Substrate 1''...Substrate with guide track 2...Magnetic 11i3...Reflection film 4...Transparent dielectric layer 5...Guide track layer 6...Holding i!
Film 7... Transparent adhesive layer 8... Heat-resistant layer tube 1-1 Figure 1-2 Figure 2-1 Figure 2-3 Figure 2-2 Figure 3-1 Figure 3-2 Figure 4-1 Figure 4-2 23 2'' Figure 5 Figure 7 Ivy Figure 9 Figure 6 Figure 8

Claims (1)

[Claims] ■, General formula % formula %] (However, 1Me represents at least one element selected from Sc, Ti, Sn, and Zn, m represents the ion valence of Me, and n r X r Y r Z are each 5.0≦n≦6
．． 0゜0<x<1.0<y≦0.8.0<z≦0.8). 2. General formula % formula %) (However, M'e represents at least one element selected from Sc, Ti, Sr+, and Zn, m represents the ion valence of Me, and nrXrVrZ are each 5.0≦ n≦6.0゜0
<x≦1.0<y≦0.8. Represents a value of O<z≦0,8. ) A magnetic film made of a metal oxide magnetic material.