JPS60201604A - Magnetic material and magnetic film of metal oxide - Google Patents

Abstract

PURPOSE:To obtain a material for a photomagnetic recording medium which enables recording or reproducing with semiconductor laser light maintaining reasonably high coercive force and lowering a curie temperature by substituting part of Fe atoms in a metal oxide of Pb-Fe system with a Cr atom and one or more atoms of specific five elements. CONSTITUTION:A material shown by a general formula PbO.n[Crx.Mey Fe(2-x-my/3)O3] is used. However, Me shows an element selected from In, Sc, Ti, Sn, Zn, Ta and Ga, (m) shows ion valence number and (n), (x) or (y) is 5.0<=n<=6.0, 0<x<=1.0 or 0<y<=0.6 respectively. In order to make such a metal oxide magnetic material, specific quantity of PbCO3, Fe2O3, Cr2O3 and either one of In2O3, Sc2O3, TiO2, SnO2 or ZnO are mixed and ground, put in a metal mold for forming and then sintered at a temperature of 1,200-1,400 deg.C. In order to make a magnetic film 2, e.g., on a substrate 1, the magnetic material is coated to a target of film thickness approx. 0.1-10mum by such a method as vacuum deposition, sputtering or ion plating.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a novel metal oxide magnetic material and a magnetic film comprising 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 O01 by vacuum deposition, sputtering, etc. A magnetic film is formed by depositing the magnetic film to a thickness of approximately 1 μm. Recording and reproduction on the magneto-optical recording medium obtained in this way is carried out as follows. That is, recording is performed at the Curie temperature of the magnetic film or This is done by heating the magnetic film by irradiating laser light modulated with a binary signal to reverse the direction of magnetization, making use of the characteristics of rapid changes in coercive force in response to temperature changes near the compensation temperature. This is done by reading out using the difference in the magneto-optical effect of the magnetic film recorded in reverse.The magneto-optical recording medium using the above-mentioned amorphous alloy magnetic material has high recording sensitivity, so it is not suitable for semiconductors. Although it has the advantage of being able to record at high speed (at a frequency of IMHz) using laser light, amorphous alloy magnetic materials, especially rare earth metal components, are susceptible to oxidative corrosion, so the magneto-optical properties of the magnetic film deteriorate over time. In order to prevent this, a protective film such as SiO, SiO, etc. is provided on the amorphous magnetic film. ) It is also known that during the formation of a magnetic film or protective film, O2 remaining in vacuum, O2.820 etc. adsorbed on the substrate surface, and O contained in the target of the magnetic alloy material. 820 etc. over time, and this oxidation corrosion is further accelerated by light and heat during recording.Furthermore, amorphous magnetic materials are easily crystallized by heat, resulting in deterioration of magnetic properties. Furthermore, as a reproduction method to improve the reproduction output, the magnetic film is made as thick as possible, and Cu, A
The reflective Faraday type, in which a reflective film made of D, Pt, Au, etc. is provided, a laser beam is irradiated onto the magnetic film, transmitted through it, reflected by one reflective film, and this reflected light is detected, produces a signal with a high S/N. Although it is advantageous in that it can be obtained, conventional amorphous magnetic films cannot be used in this method because they lack 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 represents an element represented by the general formula (1) (% formula %)], m represents the ion valence of Me, and ni
x and y are respectively 5.0≦n≦6.0', 0<X≦1.0
0<y≦6.0. ), 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 the magneto-optical recording medium must have magneto-optical properties (appropriate Curie temperature, coercive force, etc.) to enable recording and reproduction using semiconductor laser light, but especially high recording sensitivity is required. In order to obtain this, it is necessary that the Curie temperature Tc be low, and that the coercive force Hc be appropriately high in order to maintain the recorded memory stably. In general, the appropriate ranges for T c and He are 100 to 350°C for 1' c, and 300 to 6 F for c.
It is thought to be 000 oersted. This is 1' c is 1
At temperatures below 00°C, the recorded memory becomes unstable due to the laser light during playback, causing deterioration of playback characteristics.
Furthermore, it is difficult to record with semiconductor laser light at temperatures above 350°C, and on the other hand, when -1c is below 300 oersteds, the memory becomes unstable and may disappear.
In addition, if it exceeds 6,000 millimeters, the laser output and external magnetic field necessary for magnetization reversal during recording will 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 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 10 μm. However, these are Curie temperature Tc
Since the temperature is as high as 450° C. or higher, recording with semiconductor laser light is difficult as described above, and it cannot be used as is as a material for magneto-optical recording media.

Therefore, the present inventors conducted various studies based on the magnetic material of general formula (2). As a result, some of the Fe atoms in general formula (2) are replaced by Cr, In, Sc, or Ti.

It has been found that Tc is lowered by substituting with Sn and Zn atoms. At the same time, He increases in the case of Cr[exchange, but ln, Sc.

It has been found that in the case of Ti, Sn and zn@ exchanges, it decreases. For example, P b F et tt-yuz ) M2019 (M
represents Cr, In+Sc, Ti, Sn, and Zn, 2 represents the substitution number of M, and m represents the ion valence of Z. ), when each of the above atoms was substituted, Tc showed a tendency as shown in FIG. In addition, He showed a tendency as shown in Fig. 2.

Therefore, the present inventors decided to use such Cr or In.

Focusing on the substitution effects of Sc+Ti', Sn and Zn, we also focused on the Tc required for magnetic materials or magnetic films for magneto-optical recording media.
and Fe of general formula (2) considering the appropriate range of He.
As a result of substituting a part of with a combination of Cr and one of the other five types of atoms in various proportions, the general formula (1)
The inventors have discovered that the metal oxide magnetic material provides 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 Mn and one of the other five 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, P bCrx 'Mey' F e12 M
' -3y ' Olg (However, Me is In, Sc, T
represents an element selected from i, Sn and Zn, and X' is AI
, y' is the number of Me substitutions, and m is the ion valence of Me. ), the effects on T, c, and He were investigated by varying the number of substituted atoms, and the results shown in FIGS. 3 and 4 were obtained. Here, when M e = In: Fig. 3-1 and Fig. 4-1 When M e = Sc: Fig. 3-2 and Fig. 4-2 When M e = T i: Fig. 3-1 and Fig. 4-1. 3-3 and 4-3 When Me=Zn: FIGS. 3-4 and 4-4.

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.

To make the metal oxide magnetic material of the present invention, a predetermined amount of pb
co3. and Fe2O, and cr2o.

and further In2o, and 5c2o3. Tio2 +5n0
2. Any one of ZnO may be mixed and ground, put into 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 PbO.6. OCCro, It r no, tFFc
), 30-a) Pb0・6.0CCro, HT:
, g-Fez, aFO,)PbC16,6(Cr I
n,,, Fe1)t-Oz ]ρ11 Pb0・6.0 [Cr Zn a,z,,-Fe t
, uo Oa ] ρt-r pbo・s, o (Cr Sc , He Fe /,)
03 ) 0 phantom 1 PbO16,0 (Cr Sn o, if F'e 1
．． at' Os,]tF Pb0・5.6[Cr(+4(1n,,g Fe1,
3 C) 3 ] Pb0・5.8 (C: ro, ti T
i,,, Fe2. ,0. ).

In order to further increase the Faraday rotation angle and improve the magneto-optical properties, Co,
Bit V, La, Y+ Yb.

Sm, Tb, Dy'e Gd, etc. (7) fijJiti [
1jJIlt I can do Ruco.

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 magneto-optical recording medium having a perpendicularly magnetized magnetic film 2 on the substrate 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 perform perpendicular magnetization by performing heat treatment at 0 to 800° C. while applying a magnetic field if necessary. Here, the substrate material is generally a heat-resistant metal such as aluminum;
Quartz glass: GGG; Sapphire; Lithium tantalate; Crystallized transparent glass; Pyrex glass; Varicor glass; Single crystal silicon with or without surface oxidation treatment? AQ203゜AQ203・MgO, Mg0-L i F, Y2o3・
LiF, Bed, ZrO2・Y2O,,'I'hO,,
・Transparent ceramic materials such as CaO; Inorganic materials such as inorganic silicon materials (for example, Tosguard manufactured by Toshiba Silicon Co., Ltd., and 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. Now put the guide track on board 1'
is made by processing the above-mentioned organic materials by injection molding, extrusion molding, photoetching, etc. Note that the guide I/rack on the board guides the laser beam during recording and reproduction. The reflective film 3 is made of Cu, A (+, + A
g + ΔU.

Pt, TeOx, TeC, 5eAs, TeAs+TiN
, TaN, CrN, cyanine dye, phthalocyanine dye, etc., are deposited on the target surface by a method such as vacuum evaporation, sputtering, ion blasting, etc. to a film thickness of approximately 500 to 500 mm. 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 S + 02 +' S i
O+Tie,,Tie,Ce2O,l-1fO2,Be
d.

The2. It is formed by depositing St, N, 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. The protective film 6 is made of acrylic resin, polyurethane resin, polycarbonate resin, polyethersulfone resin, polyamide resin, epoxy resin, TiN, Si, N4. Ta
N+S i02. Si.

etc., in the case of resin, by coating method, in other cases, vacuum evaporation,
It is formed by depositing it on the target surface to a thickness of about 0.1 to 10 μl 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 includes 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 layer 11ii2.
(Since this layer is made of the above-mentioned inorganic material, the term "heat-resistant layer provided with a magnetic film" refers to the above-mentioned single-layer magneto-optical recording material.) The magnetic film is made of a resin such as epoxy resin, polyurethane, or polyamide. It is formed by adhering to a thickness of approximately 2 to 100 μm. That is, this transparent adhesive layer is simply attached to the substrate 1.
This is a layer for bonding the reflective film 3 on the upper layer 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. Thickness is approximately 1
Approximately 0 to 50,071 m 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.

Although the metal oxide magnetic material or magnetic film of the present invention has appropriate Tc and Hc as a material for magneto-optical recording media and has high recording sensitivity, it has oxidation and corrosion resistance that conventional products did not have. Because of its high transparency and transparency, the magneto-optical properties do not deteriorate over time, and transmitted light can also be used during reproduction, making it possible to reproduce using a Faraday rotation angle with high reproduction output.

Examples of the present invention are shown below.

Examples 1 to 8 Each target having the composition shown in the table below was used to deposit a Δg of 500 mm thick on a quartz substrate by vapor deposition,
On this quartz substrate, a 1000-thickness 5iC12 film was deposited, Ar partial pressure was 2.0 ny Torr, 02 partial pressure was 0.3 mn Torr, discharge force was 0.35 KW,
Sputtering was performed for 2 hours at a substrate temperature of 520 to 700°C to form a 0.2 μm thick magnetic film. The results of measuring the Curie temperature Tc and coercive force 11c of these magnetic films are shown in the table below.

Next, each magneto-optical recording medium obtained as described above was magnetized in one direction, and while applying a magnetic field of 500 oersted in the opposite direction of magnetization, a semiconductor laser beam with an output of 20 mV was applied to the surface of the recording medium. When recording was performed by irradiating with pulses with an intensity of 10 ml+l and a frequency of IM Hz 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 and 2 respectively show metal oxide magnetic material P b
F e , 2 m Z Mz O,,' (M is Cr, I
n. Sc, Ti+ represents Sn and Zn, Z is the number of substitutions of M,
m indicates the ion valence of Me. ), the number of substitutions is 2, and
FIG. 2 is a relationship diagram between Curie temperature Tc and coercivity angle C. FIGS. 3 and 4 respectively show metal oxide magnetic material P bCrK'May'Fe12'= x ' −
v' 019 (Me represents an element selected from In, Sen Ti, Sn and Zn, X' is the number of substitutions of Cr, y
' represents the number of substitutions of Me, and m represents the ion valence of Me. ) is a relationship diagram between the substitution numbers X' and y' and Tc and HcC. 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. 1...Substrate 1'...Guide 1-Rack] Substrate 2...Magnetic film 3...Reflection layer 4...Transparent dielectric layer 5...Guide track layer 6...
Protective film 7...Transparent adhesive layer 8...Heat-resistant layer 1 [To 4 Figure 2 Figure 5 Figure 7 Figure 9 Figure 9 i''s 6 L 矧Figure 8 Procedure Ne City Main Store; 1988 May 8EI Patent Application No. 58052, filed in 1982, 2, Name of the invention: Metal oxide magnetic material and magnetic film 3, Relationship to the person making the amendment case: Patent applicant Tokyo Metropolitan University, 1-3-6 Nakamagome, 1st Ward No. (674) Ricoh Co., Ltd. Representative Hama 1) Hiro 4, Agent 5, Subject of amendment 6, Contents of amendment 1) ``,'1°a+ Ga'' on page 4, line 17 of the specification
, delete J. 2) r C: ex OJ on page 12, line 14 [
Correct to i' Ce O, Jl. that's all

Claims (1)

[Claims] 1. General formula (%)
rXry is 5.0≦n≦6.0.0<x<1.00, respectively
<y≦0.6. ) is a metal oxide magnetic material. 2. General formula % formula %) (However, Me represents an element selected from In, Sc, Ti, Sn, and Zn, m represents the ion valence of Me, and nr
XrY is 5.0≦n≦6, 0, 0<x<
1,00<y≦0.6. ) A magnetic film made of a metal oxide magnetic material.