JPS60120503A - Metallic oxide magnetic material and magnetic film - Google Patents

Abstract

PURPOSE:To obtain the material for an optomagnetic recording medium having high recording sensitivity and good oxidative-corrosion resistance and light-transmitting properties by using a metallic oxide magnetic material consisting of a specific composition. CONSTITUTION:A part of Fe atoms in a metallic ompound of hyxagonal system expressed by MeO.n[Fe2O3] is substituted by Al or In atoms and the composition is changed into that expressed by MeO.n[Alx.InyFe2-(x+y)O3] wherein Me= Ba or Sr, O<X<=0.8, 0<Y<0.6, 5<=n<=6. Thus, recording and reproduction by a semiconductor laser beam by reducing Curie temperature with a properly high coercive force required for a memory.

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. A magnetic film is formed by depositing the magnetic film to a thickness of about .1 to 1 μrn. Recording and reproduction on the magneto-optical recording medium obtained in this way is carried out 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 without reading by utilizing the difference in the magneto-optical effect of the magnetic film recorded in this way. Magneto-optical recording media using amorphous alloy magnetic materials as described above have high recording sensitivity, so they can be recorded at high speeds (frequency I M
Although it has the advantage of being able to record with
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. To prevent this, Sin' is deposited on the amorphous magnetic film.

It is also known to provide a protective film such as 5in2 (forming method is by vacuum evaporation, sputtering, etc. as in the case of the magnetic film), but when forming the magnetic film or protective film, the 02 remaining in the vacuum, the substrate 02. adsorbed on the surface. The magnetic film is oxidized and corroded over time by H2O, etc. and 02, 820, etc. contained in the alloy magnetic target, 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, a reflective film of Cu, Aff, Pt, Au, etc. is provided on top of it, and after the laser beam is irradiated and transmitted through the magnetic film, the reflective film is The reflective Faraday method, which reflects the reflected light and detects the reflected light, is advantageous in that it can obtain a signal with a high S/N ratio, but conventional amorphous magnetic films lack translucency, so this method is It was unusable.

Purpose The purpose of the present invention is to provide a novel metallized 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 consisting of the following.

In part, the metal oxide magnetic material of the present invention is represented by the general formula (1) (%), 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 order to obtain high recording sensitivity, the Curie temperature T'c must be low, and the coercive force Hc must be low to maintain the recorded memory stably. It needs to be moderately high.

In general, the appropriate ranges for c and Hr are 100 to 350°C for Tc and 300 to 6000 for Hc.
It is thought to be Ersted. This is because when Tc is below 100°C, the recorded memory becomes unstable due to the laser beam during playback, causing deterioration of playback characteristics.
It is difficult to record with a semiconductor laser beam at temperatures above 300 °C, and on the other hand, if the llc is below 300 oersted, the memory may become unstable and disappear;
This is because in Erstets 1 to 2, the laser output and external magnetic field required for magnetization reversal during recording become large, which is undesirable.

On the other hand, hexagonal and spinel metal oxide magnetic materials have been studied for magnetic bubble impingement. Among these hexagonal crystals, for example, those represented by the general formula (2) % formula %] (where Me and n are the same as in the general formula (1)) are known. The present inventors discovered that this type of magnetic material is itself an oxide.

We focused on the fact that there is no fear of oxidative deterioration and that it has translucency even at a film thickness of 10 μm. 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 and found that F in general formula (2)
It has been found that when a part of e atoms are replaced with AQ or In atoms, Tc decreases in both cases of Ga substitution and In substitution. At the same time, it was found that 1-1c increased in the case of AQ substitution, but decreased in the case of Inl substitution. For example, An or In substituted Ba0-M7. L'e
-z O (M represents Δa or 1.n, Z represents the number of substitutions of AR or In) is as shown in Figure 1 (a in the figure) for Tc.
represents an Aβ-substituted product, and b represents an In-substituted product. ), and Hc shows a tendency as shown in Figure 2 (in the figure, a' is A
Q substituent, b' represents I I+substituted rest. ). Therefore, the present inventors focused on the substitution effect of AQ and In, and further considered the above-mentioned appropriate ranges of Tc and He required for the magnetic material or magnetic film for magneto-optical recording media, and developed the general formula (2 ) as a result of replacing a part of Fe with two metals, AQ and In, in various ratios, the general formula (1)
The inventors have discovered that the metal oxide V-columns 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 compound with AQ and In atoms, the Curie temperature can be lowered while maintaining the moderately high coercive force required for memory, and recording by semiconductor laser light can be achieved. It enables reproduction and thus can be applied 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, B ao・A, Qx'Iny' FeI+, 2
−t x'+y' , Of, 2 (X' is AQ
number of substitutions, Y' is the number of In substitutions), Tc is as shown in Figure 3 (in the figure,
C represents the case where the substitution number X' of AQ is 2.05, d represents the case where x' is 4.1, and e represents the case where X' is 1.03. ), when the number of substitutions X' in line C1, that is, AQ, is 2.05, and the number Y' of substitutions in In is 2.0, the temperature is 180°C, and H c is C' is A
When the number of substitutions X' for n is 2.05, e' is the same <x'
represents the case where is 1.03. ), the line C'
That is, when the number of substitutions X' of AQ is 2.05 and the number of substitutions Y' of Tn is 2.0, the Oersted is 2.9.

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. It has the following characteristics: high 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, Fe2O3, IMl,03, and In2O are mixed and ground, 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 Bad.5 (A Da7. In, Ver, r
03)l BaO'6 (A flax In,...
Fe7.5 O3)Ba()6(Alla>yIna
iaFe4nO, Da()5.6(A L,t In
. 3 Ver, t Oa ) SrO・5(A Ra,
Ino, Fe, 503), SrO・6(AQ, ,
In,,3Fe1.603)SrO・6(A
Qo, 25 In,, Fe(, B OJ) r S
rO・5.6 (A QelIn, jFe2.g 03
) etc.

In addition, in order to further increase the Faraday rotation angle and improve the magneto-optical properties, the metal oxide magnetic material described above may contain Go,
B i+ V, La, y, 'yb.

Metals such as Sm, TlzDy+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, in general, this magnetic material is attached to the substrate as a target layer 1 to a film thickness of about 0.1 to 10 μm using methods such as vacuum evaporation, sputtering, and ion blasting at a substrate temperature of 500 to 600°C. Just let it happen. In this way, as shown in FIG. 5, a magneto-optical recording medium having a perpendicularly magnetized magnetic film 2 on a substrate 1 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, it is
It is necessary to carry out one heat treatment at 0 to 700° C., applying a magnetic field as the case may be, to achieve perpendicular magnetization. Here, some of the substrate materials are generally heat-resistant metals such as aluminum; quartz glass; GGG; sapphire; lithium tantalate; crystallized transparent glass; Pyrex glass; single-crystal silicon with or without surface oxidation treatment: AQ2
0g+ AQ20a' MgO+Mg0I-iF, Y
20++ ・LiF+ BeatZrO2・Y2O3,
Transparent ceramic materials such as ThO2 and CaO; inorganic materials such as inorganic silicon materials (for example, 1-Sgard manufactured by Toshiba Silicon Co., Ltd. and Sumiceram P manufactured by Sumitomo Chemical Co., Ltd.), or organic materials such as acrylic resin, polycarbonate 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. 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, Bi is a ranked substrate for guide 1, 3 is a reflective film, 4 is a transparent dielectric layer, and 5
is a guide trunk layer, 6 is a protective film, 7 is a transparent adhesive layer, 8
is a heat-resistant layer. Click here to guide the board 1'
is made by processing the above-mentioned organic materials by injection molding, extrusion molding, photoetching, etc. Note that the guide track on the substrate guides the laser beam during recording and reproduction. The reflective film 3 is Cu I A Q g A g
I A u + P t , T e Ox , T e
C, S e As , T eΔs.

T iN + T' a N + Cr N + Cyanine dye, phthalocyanine dye, etc. are deposited on the target surface to a thickness of 5 by vacuum evaporation, sputtering, ion blasting, etc.
It is formed by attaching it to about 00 to 10,000 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 5
in2. Sin.

TiO2, Ti○, CeO, HfO2, Bed.

It is formed by depositing Th○, 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.

Guide 1-rank M5 is formed by applying an ultraviolet curable resin to the target surface, and then applying ultraviolet rays to cure the resin while pressing a mold having a guide groove. The protective film 6 is made of acrylic resin, polyurethane resin, polycarbonate resin, polyether sulfone resin, polyamide resin, epoxy resin, TiN, Si3N, etc.
]'aN, 5in2+ SiO, etc., is applied to the target surface by a coating method in the case of a resin, or by a method such as vacuum evaporation, sputtering, or ion blasting in other cases, to a film thickness of approximately 0.1~
It is formed by depositing 4=J to about 10 μm.

Note that this protective film is provided for the purpose of protecting the reflective film 3. The transparent adhesive M7 consists of the guide 1 provided with a reflective film 3, the reflective film of the substrate 1' with a rack, and the heat-resistant layer 8 provided with a magnetic film 2 (this layer is made of the above-mentioned inorganic material, so "layer" refers to the single-layer type magneto-optical recording material.)
It is formed by bonding a magnetic film with a thickness of about 2 to 100 μm using 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 10-5
Approximately 00 mμ is appropriate.

Recording and reproduction on the magneto-optical recording medium using the magnetic film of the present invention as described in (2) above is carried out by irradiating modulated or deflected P-light from the magnetic film or substrate side, as in the conventional method.

The metal oxide magnetic material or magnetic film of the present invention has Tc and +(c) suitable for use in magneto-optical recording media, and has high recording sensitivity. Because it has excellent oxidation corrosion resistance and transparency, there is no deterioration of magneto-optical properties over time, and transmitted light can also be used during playback, making it possible to play back using the Faraday rotation angle with high playback output. .

Examples of the present invention are shown below.

Examples 1 to 8 Using Targetera 1- having the composition shown in the table below, Ar partial pressure of 2. Onwn
T o r r, 02 partial pressure 0.3 + nn T 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 0.3 μm. 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 while applying a magnetic field of 0.5 oersted opposite to the direction of magnetization, a semiconductor laser beam with an output of 20 m11 is applied to the recording medium. Intensity 10mW and frequency I at the surface
When recording was performed by irradiating with a MHz pulse to cause magnetic reversal, recording pits with a pitch of 1 to approximately 1.5 μm in diameter were formed in each case.

[Brief explanation of the drawing]

FIGS. 1 and 2 show metal oxide magnetic material B a O
” M Z F ert,, -z Org, g (M
is the number of substitutions Z for AQ or I r+, and the Curie temperature T c
and the relationship diagrams with coercive force Hc, FIGS. 3 and 4, respectively.
Metal oxide magnetic material B ao-ADH'In,' Fel1. z-[X'
+y', Ors, the number of substitutions Y' of In in t (X' is the number of substitutions of An, Y' is the number of substitutions of 1.n), and Tc
and Hc, and FIGS. 5 to 9 are configuration diagrams of an example of a magneto-optical recording medium using the magnetic material or magnetic film of the present invention, respectively. Lines a, a'...AQ substitution product Lines, b'...In substitution product line c, c' - x' = 2.05 ll [substitution line d
-x' = 4.1 AQ substituent line e, e' - = x' = 1.03 Au[il substitution l...Substrate 1'...Substrate 2 with guide track layer''...magnetic Film 3... Reflective film 4... Transparent dielectric layer 5... Guide track layer 6...
・Protective film 7...Transparent adhesive layer 8...Heat-resistant layer Patent applicant: Ricoh Co., Ltd. - Ougi 10 10 I speed Y' Fly 5 figure Class 6 Blasphemy 9 figure

Claims (1)

[Claims] ■, 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