JPS60231304A - Metallic oxide magnetic material and magnetic film - Google Patents

Abstract

PURPOSE:To obtain the titled material which has high recording sensitivity as well as excellent oxidation resistance and light-transmitting property and is suitably employed as a material particularly for a photomagnetic recording medium, by employing a specific composite metallic oxide. CONSTITUTION:A magnetic material represented by the formula I is employed. In the formula: A represents two or more elements selected from among Ba, Sr and Pb; Me is an element selected from among In, Ti, Sn, Zn, Ta and Ge; m represents the number of Me ion valences; and the conditions of n, x, y and z are 5.0<=n<=6.0, 0<x<=1, 0<y<=1.0, and 0<z<=1.0. This magnetic material is produced by, e.g., mixing together BaCO3 or SrCO3, PbCO3, Fe2O3, Cr2O3, and any one of In2O3, TiO2, SnO2, ZnO, TaO2 and GeO2 by a predetermined amount each, powdering this mixture, molding the powdered material in a mold with an appropriate configuration, and sintering the molded material at 1,200-1,400 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [1] The present invention relates to a novel metal oxide magnetic material and a magnetic film made of the same.

Jōmei W Technique - 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 material to a thickness of about .1 to 1 μm. Recording on the magneto-optical recording medium obtained in this way,
Reproduction 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 amorphous alloy magnetic materials as described above have high recording sensitivity and have the advantage of being able to record at high speeds (at a frequency of IMHz) using semiconductor laser light. In particular, the rare earth metal component is susceptible to oxidative corrosion, so there is a major drawback in that the magneto-optical properties of the magnetic film deteriorate over time. To prevent this, S
It is also known to provide a protective film such as jO, 5jO2 (the formation method is the same as for the magnetic film, such as vacuum evaporation or sputtering), but when forming the magnetic film or the protective film, 02 remains in the vacuum. , 02. adsorbed to the substrate surface. l-1,
o7.1 contained in targets of 0 grade and alloy magnetic materials
-The magnetic film is oxidized and corroded over time due to t2o, etc.-
This oxidative corrosion is further accelerated by light and heat during 1-1 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 was made as thick as possible, and secondly, Cu, A
The reflective Faraday type, in which a reflective film of Q, Pt, Au, etc. is provided, a laser beam is irradiated and transmitted through the magnetic film, and then reflected by the reflective film and this reflected light is detected, a signal with a high S/N can be obtained. However, conventional amorphous magnetic films cannot be used in this method because they lack light transmittance.

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 a novel metal oxide magnetic material made from this metal oxide magnetic material. The purpose is to provide a magnetic film (II-).

Structure The metal oxide magnetic material of the present invention has the general formula (+)AxO-n
[Cry-MezFe+2-V-&Z) 011
] (However, A represents at least 3 to 2 or more of Ba, Sr, or PB, and Me, In, Tj, Sn, Zn
.

Indicates an element selected from Ta, Ge, m is Me
The ion valence of n+ X+ Y+ z is 5.
0≦n≦6.11. (1<x≦1,0<y≦1.0゜0<z≦1.0), and the magnetic film is made of a metal oxide magnetic material having the above general formula. be.

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 Hc must be low. is required to be moderately high.

In general, the appropriate range for Tc and +-(c is 100 to 350°C for Tc, and 300 to 5000 for He.
It is thought to be Ersted. This is because when Tc is below 100°C, the recorded memory becomes unstable due to the laser light during playback, causing deterioration of playback characteristics.
At temperatures above 50°C, it is difficult to record with semiconductor laser light; on the other hand, when He is below 300 oersteds, the memory becomes unstable and may disappear, and when recording below 5000 oersteds, it is difficult to record with semiconductor laser light. This is because the laser output and external magnetic field required for magnetization reversal become large, which is undesirable.

On the other hand, metal oxide magnetic materials have been studied as magnetic bubble materials. Among these hexagonal crystal systems, for example, those represented by the general formula (2) % formula %] (where A 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 10 μm. However, these are Curie temperature Tc
Since the temperature is as high as 450° C. or more, 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) were replaced with Cr, Tn, Tj, Sn, 7. n.

It has been found that Tc is lowered by substitution with Ta and Ge atoms. At the same time, Hc increases with Cr substitution, but with In and Ti.

It has been found that Sn, Zn, Ta and Ge substitutions result in a decrease. In addition, when a part of Ba or Sr is replaced with pb, the above-mentioned replacement effect of Cr, In, etc. is the same, but
Residual magnetization can be increased. For example, Sr, HPb, 7.
Fe, 2- = x'Mx' 019 (M is Cr
.

Indicates In, Tj, Sn, Zn, Ta and Ge,
y' represents the number of substitutions of M, and m represents the ion valence of M. ), when each of the above atoms was substituted, Tc showed the trends shown in Figures 1-1 to 1-6. Also H
Regarding e, the trends shown in Figures 2-1 to 2-6 were shown. Although not shown, the same was true when Sr in the formula was Ba. Note that in order to clarify the difference between CrM substitution and other atomic substitutions, the results of Cr substitution are illustrated in all the figures.

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

Focusing on the substitution effects of Tj, Sn, 7:n, Ta and Ge, and further considering the appropriate ranges of Tc and I-1c required for the magnetic material or magnetic film for magneto-optical recording media, the general formula ( As a result of replacing a part of Fe in 2) with a combination of Cr and one of the other six types of atoms in various proportions, the metal oxide magnetic material of general formula (1) can be used as a magneto-optical recording medium. The present invention was achieved by discovering that it provides excellent properties.

In this way, the present invention solves the problem of the general formula (2
) By substituting some of the Fe atoms in the metal oxide with Cr and - of the other six types of atoms mentioned above, the Curie 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, S'z, +tPhg,
71Cry'M82H'FJ2-y'-2sa,z'01
g (However, Me is In, Ti, Sn, Zn, Ta
and Ge, y' is the number of Cr substitutions, Z'7- is the number of Me substitutions, and m is the ion valence of Me. When the effect on Tc and )lc was investigated by varying the number of substituted atoms in ), the results shown in FIGS. 3 and 4 were obtained. Although not shown, the same was true when Sr in the formula was Ba. here.

When Me=In: Figure 3-1 and Figure 4-1 Me=T
In the case of i: Fig. 3-2 and Fig. 4-2 When Me=Sn: Fig. 3-3 and Fig. 4-3 When Me=Zn: Fig. 3-
Figure 4 and Figure 4-4 When M e = Ta: 3rd-
5 and 4-5. When Me=Ge: FIGS. 3-6 and 4-6. Further, to explain the case where Me=Tn as an example, the number of substitutions y' of Cr is 2.24 and the number of substitutions Z' of Tn
When is 1.0, Tc is 250°C from Figure 3-1.

Hc is 9000 e from Figure 4-1. Me is Ti
.

Similar trends were observed in the cases of S n r Z n r Ta and Ge. Due to these Tc and Hc properties, the metal oxide magnetic material or magnetic film of the present invention can of course be applied as a material for magneto-optical recording media that performs recording and reproduction using 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.
C01] or 5rCO, and PbC0, and Fe2O8 and C
r2O3 and further Ta20. ,.

Any one of TiO2, SnO, 7,nO, TaO2, and Gem2 may be mixed and pulverized, placed in an appropriately shaped mold, 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 B aa, tP b, ro + 6.0 [Cr 6
, 31. T n ,,rr Fe t,tp Oa
] BAaf P b (,, po ・6.0 [Cr
, 3p T, ] 6. rFF e 1. tt Oa)
Ra(B P b6.10 ・6.OCCro3r T
a6. tr Fe tjr O3]Ba, 4Pb,,
0 ・6. OCCr, 3p Zn, /l Fe t
, ti-On ) Rqe, t P bc, to ・6-
0 (Cr, , Ge , 2/ F e /, $?
Os ]B a,, rP bo, FO' ”-0[:
Cr,j,sn,,zlFe+,470a]
Sro, hPb6cm0' 6.0 (Cr o, 3
(r n 6)g Fe t'l Os ]Sr, ),
-Pbc, io + 6. OCCr,, p Ti 6.
tt Fe Bt On) Ran, ssr,, 0 ・
6. OCCr, 3pTi, rgFe7. rf
Os ) Ba, ysr,, O' 6.0 (Cr,,,
-In,, Fe 7t, f, o, '3 are mentioned.

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

r) Metals such as y 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 700°C. That's fine. In this way, as shown in FIG. 5, a magneto-optical distribution medium having a perpendicularly magnetized magnetic film 2 on a substrate i 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 ~800° C. while applying a magnetic field if necessary. 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; Silicon: AQ203゜All, 03 ・MgO, MgO・LjF, Y2O,・
1, jF+ Beon 7. rO2”I20.J, Th
Transparent ceramic materials such as e, 'CaO; inorganic silicon materials (
For example, inorganic materials such as Toshiba Silicon Co., Ltd.'s Toss Guard and Sumitomo Chemical Co., Ltd.'s Sumicella tzp) 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 substrate with guide tracks is made by processing the above-mentioned organic material by injection molding, extrusion molding, photo-etching, or the like. Note that the board guide track is recorded.
It guides the laser beam during playback. The reflective film 3 is all AQ, Ag, Au, Pl-.

TeOx, TeC, 5eAs, TeΔs, T jN
, TaN.

It is formed by depositing 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 SiO2, Sin, TiO2, T-io,
CeO.

It is formed by depositing HfO2, Bed, The2j 5i9N4, etc. on the target surface in the same manner as described above to a 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 ultraviolet curable resin to the target surface and then curing the resin by irradiating ultraviolet rays 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, TiN, 5j3
N, t + TaN, 5jO2゜SiO, etc. are coated on the target surface by a coating method in the case of resin, or by vacuum evaporation, sputtering, ion blasting, etc. on the target surface.
．． It is formed by adhering to a thickness of about 1 to 10 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 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 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.

Effect The metal oxide magnetic material or magnetic film of the present invention has appropriate Tc and l-1c as a material for magneto-optical recording media, and although it has high recording sensitivity, it has oxidation corrosion resistance that conventional products did not have. Since the material is transparent and magneto-optical, its 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 that provides a high reproduction output.

Examples of the present invention are shown below.

Examples 1 to 10 A quartz substrate whose surface was optically polished using each target having the composition shown in the table below. OnwnT
orr, 02 partial pressure 0.3nmTorr, discharge force 0.3
A magnetic film with a thickness of 0.3 μm was formed by sputtering for 4 hours at 5 KW and a substrate temperature of 520 to 700°C. Curie temperature Tc and coercive force Hc of these magnetic films, ti
-The measured results are shown in the table below.

Next, each of the magneto-optical recording media 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 y6 with an output of 15-201 is applied to the recording medium. When the surface was irradiated with a pulse having an intensity of 10 m1+1 and a frequency of IM117 to cause magnetic reversal and recording, recording bits with a bit diameter of about 1.5 μm were formed in each case.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 show metal oxide magnetic material S r, +
2t P h, 2t F e +p Δ1' M x
O19<M is r, r, In. Ti, Sn, Zn, Ta, and Ge are shown, y' is the number of substitutions of M, and m is the ion valence of M. ) in the number of substitutions
', Curie temperature Tc, and coercivity II l-(c. :rv'M
e,' F el:2. −y′ −color, Z′
OIQ (M e is I n, T i, S n, 7
．． Indicates an element selected from n, Ta, and Ge, y' indicates the number of substitutions of Cr, Z' indicates the number of substitutions of Me, and m indicates the ion valence of Me. ) and the number of substitutions y' and Z' in J3, and Tc
and ) (c). Figures 5 to 9 are configuration diagrams of examples of magneto-optical recording media using the magnetic material or magnetic film of the present invention. 16-1...Substrate 1 '...Substrate with guide track 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 18- Fig. 5 Fig. 7 Fig. 9 Fig. 6 Fig. 8

Claims (1)

[Claims] 1. General formula % Formula %] (However, A represents at least two or more of Ba, Sr, or Pb, and Me is an element selected from In, Ti, Sn, Zn, Ta, and Ge. , m indicates the ion valence of Me, and n+X+'/+Z are respectively 5.0≦n≦6.0.0<x≦1.o (y≦1.0゜0
<z≦1.0. ) is a metal oxide magnetic material. 2. General formula % Formula %] (However, A represents at least two or more of Ba, Sr, or Pb, Me represents an element selected from In, Ti, Sn, Zn, Ta, Ge, and m represents Indicates the ion valence of Me, n + x+ V +
Z is 5.0≦n≦6.0.0<x≦LD<y≦1.
0°0<z≦1.0. ) A magnetic film made of a metal oxide magnetic material.