JPH0330302A - Amorphous oxide magnetic compact and magnetic core and magnetic recording medium - Google Patents

Abstract

PURPOSE:To obtain an amorphous oxide magnetic compact which exhibits a ferromagnetic property by constructing an oxide magnetic compact which contains oxides, e.g. rare earth elements, manganese, and the like in specific proportions substantially from an amorphous phase. CONSTITUTION:In an amorphous oxide which contains oxides (XO), e. g. rare earth elements (Ln) including Y, manganese (Mn), an element A (A is at least a kind of elements, out of the elements, e.g. Ca, Sr, Ba, and Pb), and an element X (X is at least a kind of elements, out of the elements, e.g. B, Bi, Si, Mg, Mo, V, Zn, P, and Ge) in proportions described by expression II, after the above oxides (XO) are converted into the oxides expressed by expression I (where XOs are converted into each element, e.g. B2O3, Bi2O3, SiO2, MgO, MoO3, V2O5, ZnO, P2O5, and GeO2), this magnetic compact is formed of substantially an amorphous phase consisting of XO and a fine crystal or the amorphous phase consisting of (Ln1-XAx)MnO3-delta where delta<1. Exhibiting a ferromagnetic property, an amorphous oxide magnetic compact which is suitable for practical use is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an amorphous oxide magnetic material having ferromagnetism.

(Prior Art) Amorphous magnetic materials exhibit physical properties that are not found in crystalline materials, and therefore research is progressing in various places. A typical example is an amorphous magnetic alloy obtained by ultra-quenching a melt of a metal element such as Co, Fe, or Ni and a metalloid element such as 81 or B. This amorphous magnetic alloy has excellent magnetic properties and has been put to practical use in many fields such as magnetic heads and switching power supplies.

On the other hand, no oxides have been found that exhibit ferromagnetism above room temperature, and there are only a few 'e, O's.

Fe, O, -To-X system with main components (T=Ca, B
a.

Zn, Mg: X = B15Oa, BzOs
, 810g), spinel MFe,O, (M=F
e, Co, Ni, Mn, Cu, Mn-Zn) @
Main components MFe, O, -P, 0! (For example, Functional Materials, April 1984 issue, p. 1.J, Mag, Mag, Mater, 54-
57 (1986) 296.

Applied Physics Vol. 56 No. 5 2596, etc.). All of these are amorphous oxides whose main component is the oxide of re.When rolled up with a magnet, they appear to be ferromagnetic at first glance, but when the Mössbauer spectrum is measured, they show paramagnetic spectra at room temperature, so-called ferromagnetic. It is known that there is no magnetic spin alignment.

(Problems to be Solved by the Invention) At present, no effective K material exhibiting ferromagnetism in an amorphous oxide system has yet been found.

The present invention takes this point into consideration and aims to provide a novel amorphous oxide magnetic material suitable for practical use.

[Structure of the invention]

(!!! Means and operation for solving the problem) The present invention is a completely new type of amorphous magnetic oxide which has not been known in the past, and which has Mn as a main component. That is, the present invention provides rare elements (Ln) containing Y, manganese (Mn), element A (A: at least one of Ca, Sr, Ba, and Pb), and element X (X: B*B i, Si
+ M K + Mo T V T Zn *P and G
(1-y)(
Ln, -xAxMn03:) ・ycXO] (However, X01-1:B103
, Bi2O3, 8i0. , MgO, Mob,
, V2O,.

ZnO,? , 0. and converted to Ge01) αl≦X≦1
．． 0 0.1≦y≦0.7, an amorphous phase consisting essentially of XO and (L n 1-xAx )M
It is an amorphous oxide magnetic material characterized by consisting of microcrystals or an amorphous phase consisting of n 03-δ (however,
δku1). The magnetism of conventional amorphous magnetic oxides originates from super-exchange interactions between Fe ions via oxygen ions, but the magnetism of the amorphous magnetic oxides of the present invention is derived from super-exchange interactions between Fe ions through oxygen ions. This is due to the interaction between ions, and the mechanism of magnetism is also different between the two, making them completely new amorphous magnetic oxides that have never existed before.

In the above amorphous magnetic oxide of the present invention, human.

0 and dove are elements essential for obtaining ferromagnetism, and X satisfies 0.1≦X≦1.0. If X is outside this range, it will be difficult to obtain ferromagnetism at temperatures above room temperature, so keep it within this range. Further, since the saturation magnetization decreases when X) is 0.8, it is preferable that X≦0.8, and furthermore, that X≦0.6. The [XO] component is an effective component for promoting amorphization, and its amount y is 0.1≦y≦0.7. y
If it exceeds 0.7 k, it becomes difficult to obtain ferromagnetism above room temperature, and when y<o, x, it is difficult to obtain translucency, so this range was selected. Preferably, 0.1≦y≦O55, and K is 0.2≦y≦0.5.

In addition, from the point of obtaining large magnetization in Ln element, L
a is preferable, and it is desirable that 29a in the Ln component is more than La. Furthermore, it is desirable that the content be 70 at% or more.

Among the XO components, B,03 is preferable because it is easy to become amorphous, and B30.03 is preferable among the XO components. It is desirable that Furthermore, it is desirable that the content is 50 at% or more. In addition, since the addition of B1103 increases the Faraday rotation angle, 5at in the XO component
It is effective when added in an amount of % or more.

Furthermore, when a portion of the dovetail is replaced with Co, the coercive force increases, making it a preferred material for minute hands that require high coercive force, such as those used in magnetic recording media. However, if there is a large number of substitution hazards, the Chierly point will drop beyond the practical range, so in practice it is preferably 0.1 to 50 atoms. When expressed in the same manner as the general formula above, (1-y) (L' 1 xAxMni -z cO
, O, ) ” y (X O) 0.1≦X≦1.0 0.1≦y≦0.7 2 ≦0.5.

Further, in the A component, Sr is preferable from the viewpoint of increasing solubility magnetization and the Curie point, and it is desirable that Sr accounts for 5 Qat% or more in the A component. Furthermore, it is desirable that it is 7Qat% or more.

In addition, the amount of oxygen in the amorphous material changes somewhat depending on manufacturing conditions and the like, resulting in, for example, oxygen defects.

The amorphous magnetic oxide of the present invention can be produced by conventional methods for producing amorphous materials, such as liquid quenching methods such as twin roll method and single roll method, vapor phase quenching method such as sputtering method, and mechanical alloying method. It can be manufactured by known methods.

Hereinafter, the amorphous magnetic oxide of the present invention was prepared by a liquid quenching method.
An example of the method for creating the image will be explained in detail.

First, various oxides, carbonates, nitrates, etc. that become oxides by calcination, such as La1Os IMn, are used as additives.
C03, CaC05 (S r C01, naco, ,
Pbo), B*Os, etc. are mixed in a predetermined ratio and calcined at a temperature near the melting point to form composition (1-y) I:I.
, nl-xAxMnOs:) to produce a working y (XO). Next, this composition is filled into a crucible, heated and melted in the air at a temperature approximately 50 to 200°C higher than the melting point, and the melt is passed through high-pressure gas (air, Ar, etc.) using high-speed rotating rolls (twin rolls). (Maku is a single roll) Spray on top, 104
By ultra-quenching at ~b, a ribbon-like amorphous material is obtained.

In this case, it is easy to obtain an amorphous material when the plate thickness is 40 μm or less. When this is exceeded, crystalline materials tend to form partially.

Next, an example of a method for producing the amorphous magnetic oxide of the present invention using a vapor phase quenching method will be specifically explained using a sputtering method. First, in the same manner as described above (1-
y) (Lnx-xAxMnOsmlΦy
A composition (XO) is prepared and used as a sputtering target. This target was fixed at a predetermined position in the sputtering equipment, and after the vacuum was evacuated to a degree of vacuum of I Maintain the inside of the device at the above constant pressure.Next, with the target as the cathode and the substrate as the anode, a voltage is applied between them to cause a discharge.
Argon bombards the target with oxygen ions to cause reactive sputtering and deposit the target material on the substrate. The composition of the resulting film may not necessarily be the same as the composition of the target, but in that case, it can be removed by changing the composition of the target appropriately.

The amorphous oxide of the present invention has high light transmittance, particularly in the visible to infrared region. In addition, the degree of crystallization is as high as about 550°C or higher, for example about 650°C, which is higher than that of conventional Fe.
, 03- This is larger than the 400° C. of TO-X-based and spinel-based amorphous oxides, and the thermal stability is correspondingly higher.

Further, it is possible to vary the properties, such as coercive force, Curie point, etc., widely according to requests. For example, the basic composition has a small coercive force and exhibits soft magnetism, but it is possible to increase the coercive force by adding Co and change it to hard magnetism suitable for magnetic recording media.

Next, a magnetic core using the amorphous oxide magnetic material of the present invention will be explained.

Conventionally, so-called soft magnetic materials such as permalloy, soft ferrite, sendust, and amorphous alloys have been used for magnetic cores. However, since the above-mentioned materials except soft ferrite are metal materials, their magnetic permeability is greatly reduced at high frequencies, particularly at frequencies exceeding I MHz. Also, since Soft 7 Elite has a high specific resistance, its frequency characteristics are good, but its magnetic permeability itself is not very large. On the other hand, the amorphous oxide magnetic material according to the present invention has high magnetic permeability even at high frequencies, and can constitute an excellent magnetic core particularly for high frequencies.

In manufacturing, a thin film of amorphous oxide magnetic material is formed on a substrate by sputtering method, etc., and a coil is wound.
Alternatively, a conductor pattern corresponding to a coil may be formed. Further, the thin film may be formed into multiple layers with an insulating layer interposed therebetween, if necessary.

In addition, the amorphous oxidized magnetic material obtained by liquid quenching method etc. can be crushed and
A magnetic core can also be obtained by molding. As the pulverizing means, the same methods as those used in ordinary ceramic manufacturing methods such as a ball mill, jet mill, and vibration mill can be used.

To produce a magnetic core using the amorphous oxide powder produced as described above, it is necessary to knead it with a binder resin such as epoxy or nylon or glass powder, and mold it into a certain shape. . As the molding method, high pressure compression, injection molding, heating at a temperature below the crystallization temperature, etc. can be used.

The magnetic core thus obtained is very effective as a high-frequency magnetic core for high-frequency transformers, inductors, and the like.

The amorphous oxidized magnetic material of the present invention is also effective as a magnetic recording medium.

In general, magnetic thin films that have an axis of easy magnetization perpendicular to the film surface and a Curie temperature higher than room temperature can be used as high-density perpendicular magnetic recording media or irradiated with a light beam such as a laser beam. It can be used as a high-density magneto-optical recording medium for recording and reproducing information. Co-Cr is used as such a recording medium.

Bayx light, polycrystalline thin film such as MnB1, G
Compound single crystal thin film such as dIG (gadolinium iron garnet), Tb-Fe, Gd-Co, Tb-Co
, Tb-Fe-C.

There are rare earth-iron group amorphous alloy films such as.

A polycrystalline metal thin film such as MnB 1 has a key IJ of -71 degrees (
Writing is performed using TC”360.
It has the disadvantage that it requires a considerable amount of energy to write because it is as high as approximately 10°C. Furthermore, since it is a polycrystalline material, it is necessary to create a thin film with a stoichiometric composition, and it also has the disadvantage that it is difficult to mold.

Furthermore, since a film of GdIG or the like is formed on a GGG (gadolinium gallium garnet) single crystal substrate, there are drawbacks such as the fact that the magnetic properties are easily affected by the condition of this substrate and that it is difficult to obtain a large-area substrate.

On the other hand, rare earth metals such as Gd-Co and Tb-Fe
Iron group amorphous alloy thin film (RE-TM, l exchange) ij: A magnetic thin film of any size can be formed, the composition can be easily controlled, and the reproduced S/N ratio is low because there are no grain boundaries. It has advantages such as good performance, and has been actively researched as a magneto-optical recording medium. However, this RE-TM film generally has a problem that the magneto-optical 7 Alladay effect and the Kerr effect are small, the C/N ratio is insufficient, and the corrosion resistance is poor.

On the other hand, the amorphous oxide magnetic material according to the present invention has a high light transmittance of <4! In addition to having high light transmittance in the visible to infrared region, the amorphous oxide of the present invention can also form a perpendicularly magnetized film with a high coercive force of 1 kOe or more, which is effective as a magneto-optical recording medium. Obtainable. Since the Curie point Tc of such a thin film is relatively low at about 100 to 170° C., a small amount of laser power is required for writing in magneto-optical recording, and a semiconductor laser can be used. In addition, the Faraday rotation angle is large, over 104 degrees/field, and the light absorption coefficient is relatively small, so the C/N
It is possible to provide a recording medium with a large ratio. Furthermore, since it is an oxide, it has high corrosion resistance, and its properties are extremely low when used for a long time.

In the present invention, the magnetic recording medium is preferably manufactured by an evaporation method. Examples of evaporation methods include high frequency sputtering, direct current sputtering, magnetron sputtering, ion beam sputtering, ion blating, electron beam evaporation, and vacuum evaporation. The film according to the present invention is a perpendicularly magnetized film having the entire easy axis of magnetization in the direction perpendicular to the film surface.

The substrate may be a non-magnetic substrate that is easy to mold and does not affect the magnetic properties of the magnetic thin film, such as a resin substrate such as vinyl chloride, polycarbonate (PC), acrylic resin, or a glass substrate. Can be used.

(Example) Hereinafter, the present invention will be explained in more detail by showing examples.

Example-1 Each raw material with a purity of 99.9 yen was mixed in the proportions shown in Table 1, and after calcining, it was melted by high frequency heating in a platinum crucible with a diameter of 1, and was placed between twin rolls rotating at high speed. Blow out argon gas at a pressure of kg/cr4. The size of the obtained sample varied slightly depending on the composition, but had a width of 3 to 1 Os11, a length of 10 to 40 m, and a thickness of 10 to 20 μm, and all exhibited brownish translucency.

It was confirmed by powder X-ray diffraction that each sample was amorphous. Table 1 shows the magnetization values and Kie IJ++ points measured using a VSM (sample shaking mJ type magnetometer). 0.6 (La o, a S r., Mn
O3]0.4B20. The powder X-ray diffraction results for each are shown in the first factor. Moreover, the temperature change of magnetization determined by VSM of the same sample is shown in FIG. The Keely points shown in Table 1 were determined from this temperature change in magnetization.

It can be seen from Table 1 that the amorphous oxide of the present invention has large magnetization above room temperature.

Next, nine examples of fabrication using the sputtering method will be described.

After sintering the oxide with the composition shown in Table 2, it was processed into a disk with a diameter of 5 inches, the surface was made smooth, and it was placed on the target part in a high-frequency sputtering device, and then placed in a chamber using a glass plate as a substrate. The pressure was reduced to 1×10 Torr. Thereafter, a mixed gas containing Ar and O2 at a ratio of 1=1 was introduced into the chamber, and the pressure was set to 3×10'rorr. When the gas pressure became constant, a voltage was applied to the high frequency power source, and sputtering was performed while rotating the substrate at 1 Orpm. The substrate temperature was not particularly controlled. The obtained film was confirmed to be amorphous by X-ray diffraction. Table 2 shows the gL of magnetization measured using VSMt.

(Hereinafter in the margin) Table 1 (hereinafter in the margin) Next, the structure of sample No. 12 in Table 2 was analyzed by the Xa resonance scattering method. Figure 3 shows the radial distribution function obtained from this experiment. In the figure, crystalline 8rMn0
3. LaMnOs O L Q: Amorphous '51 Bx
The values of each interatomic distance in Os are shown, and the radial distribution function of this sample shows peaks at positions corresponding to these interatomic distances. This means that this sample is 7-
v-ruf 7xB, 0. This shows that La, Sr, and Mn0- are in a separated state. The latter's La oy
8 r h, b/ixx Os 6 is considered to be close to crystalline based on its peak position, but the X-ray diffraction shown in Figure 1 shows that this sample is amorphous, so Laa, Sr , , MnO, -δ has an amorphous structure similar to a crystal or is composed of microcrystals that cannot be confirmed by X-rays. The reason why this sample exhibits ferromagnetism is because the magnetic phase La, 7SraJMnO, -
This is considered to be a result of δ and the amorphous phases B and α being substantially separated from each other.

Similar experiments were conducted on other systems of the present invention, and it was confirmed that they had similar structures.

〔Effect of the invention〕

Since the amorphous magnetic oxide of the present invention has an amorphous structure, the composition of constituent elements can be varied over a wide range. Therefore, an oxide having arbitrary magnetic properties depending on the purpose can be easily obtained.

Since the oxide of the present invention is amorphous, it is magnetically and optically isotropic, and since there is no grain boundary, there is no magnetic or optical disturbance. Also, since it is an oxide, it has a high specific resistance. Therefore, this oxide has excellent properties as a magnetic material and exhibits high light transmittance.

Therefore, it can be used in a wide range of applications, including, for example, magnetic core materials for high frequencies, optical isolators, optical CT, magneto-optical materials such as magneto-optical recording media.

[Brief explanation of drawings]

Figure 1 is an X-ray diffraction diagram, Figure 2 is a temperature characteristic diagram of magnetization, and Figure 3 is a diagram of temperature characteristics of magnetization.
The figure is a structural analysis diagram.

Claims (4)

[Claims] (1) Rare elements (Ln) including Y, manganese (Mn)
, A element (A: at least one of Ca, Sr, Ba and Pb) and X element (X: B, Bi, Si, Mg, Mo, V
, Zn, P and Ge) oxide (XO)
(1-y) [Ln_1_-_xAxMnO_3]・y[
XO] (where XO is B_2O_3, Bi_2O_3, SiO_2, MgO,
(converted to MoO_3, V_2O_5, ZnO, P_2O_5 and GeO_2) In the oxide magnetic material containing in the ratio of 0.1≦x≦1.0, 0.1≦y≦0.7, substantially XO
an amorphous phase consisting of (Ln_1_−_xAx)MnO_
An amorphous oxide magnetic material characterized in that it consists of microcrystals consisting of _-_δ (δ is less than 1 oxygen defect) or an amorphous phase. (2) The amorphous oxide magnetic material according to claim 1, wherein 50 atomic % or less of Mn is replaced with Co. (3) The magnetic core according to any one of claims 1 to 2, characterized in that it is formed from the amorphous oxide magnetic material. (4) The magnetic recording medium according to any one of claims 1 to 2, characterized in that the amorphous oxide magnetic material is used as a recording medium.