JPS63270472A - Manufacturing method of superconducting oxide thin film - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a superconducting oxide thin film used for electronic materials and the like.

[Prior Art and Problems to be Solved by the Invention] Conventionally, as multi-metal oxides exhibiting superconductivity, those consisting of copper, rare earth metals, and Group II metals of the periodic table have been known. ((1) J, G.

Bednortz and ni, ^, Muller
, Zeitshrlft fuelphysik
B64 (1986) 189. (2)
S, Uchida, S.

Tanaka et al, Japanese
Journal of applied9hy
sics 26 (1987) 1.1 (3)P
,H,)for,C,W.

Chu et al., Physical r.
view 1etters 58 (1987
)908).

However, such multi-metal oxides are ceramic materials and have poor moldability, making it extremely difficult to produce thin films using this material.

[Means for Solving the Problems] The present inventors have conducted extensive research on a method for easily producing a thin film made of the above multi-metal oxide. the result,
As a result of investigating a method of molding this multi-element metal oxide using its precursor instead of directly molding it, it was discovered that a thin film could be easily obtained by the method of the present invention, and the present invention was completed.

That is, the present invention involves dissolving a mixture of [A] an organic compound of copper, [B] an organic compound of a rare earth metal, and EC] an organic compound of a group N metal of the periodic table, and reacting with water to form a sol. The present invention provides a method for producing a superconducting oxide thin film, which is characterized in that the produced sol is coated or cast onto a substrate to form a thin film, and then fired.

In the present invention, an organic compound of copper is used as the [^1 component].

The organic compound is not particularly limited, but suitable examples include alkoxides such as methoxide, ethoxide, and isopropoxide, azyloxides such as acetoxide, and chelate compounds such as acetylacetonate.

Next, a rare earth metal organic compound is used as the [B] acid component.

There are no particular restrictions on the rare earth metal, but lanthanum, yttrium, ytterbium, etc. are preferably used.
Suitable organic compounds include these methoxides,
Alkoxides such as ethoxide and isopropoxide,
Azyloxides such as acetoxide and chelate compounds such as acetylacetonate are used.

Further, as the acid component [C], a group II metal organic compound of the periodic table is used. The Group II metal is not particularly limited, but barium, strontium, calcium, etc. are preferably used, and preferred organic compounds include alkoxides of these metals such as methoxide, ethoxide, and isopropoxide, and azyloxides such as acetoxide. Chelate compounds such as acetylacetonate, etc. are used.

The method of the present invention begins with the above-mentioned [A] organic compound of copper.

[B] Rare earth metal organic compound and [C] Periodic table I
The mixture of Group I organic compounds is dissolved in a solvent to obtain a solution. Suitable solvents include ethyl alcohol, isopropyl alcohol, butyl alcohol, dioxane, tetrahydrofuran, benzene, toluene, xylene, and ethylbenzene.

Next, water is added to this solution to form a sol.

The amount of water is 0.2 to 5 equivalents, preferably 0.5 to 1 equivalent, based on the total amount of metal elements. If the water content exceeds 5 equivalents, the solution will gel and become difficult to mold. In this case, hydrochloric acid, acetic acid, or the like may be added as an oxidation catalyst, if necessary.

Further, this sol-like solution is coated or cast onto a substrate in an oxidizing atmosphere such as air to obtain a precursor thin film.

The precursor film is then fired in an oxidizing atmosphere, such as air, containing at least 5% by volume of oxygen, with the balance being an inert gas such as nitrogen or argon. Firing temperature is 70
The temperature is 0 to 1.500°C, preferably 800 to 1,200°C. If the firing temperature is less than 700°C, the removal of organic matter will not be sufficient, and if it exceeds 1,500°C, defects such as voids will likely occur, both of which are not preferred.

In this way, the thin film of the present invention can be obtained. Here, the thickness of the thin film is desirably 001 to 1100p, but 0.
5 to 10 pm is suitable. If the film thickness is less than 0.1 μm, the mechanical strength will be insufficient, and if it exceeds 1100p, oxidation will be insufficient and a homogeneous film will not be obtained.

In the present invention, it is necessary to select the components and blends so that the oxide thus obtained has the following composition ratio.

(M'+-x・M”x)n-CL104-y In the formula, M1 is a rare earth metal, M2 is a metal from group 1f of the periodic table, X is 0,
05-0.95. n is 1 to 3.3F is 0 to 2, preferably X is 0.1 to 0.9゜n is 2 to 3
．． y is 0-1.

The thin film obtained in this way can be further processed as necessary.
It is preferable to perform heat treatment in a reducing atmosphere before use.

[Example] Next, the present invention will be explained in detail with reference to examples.

Example 1 13.0 g of copper acetylacetonate, 18.9 g of lanthanide q-reli isopropoxide, and 8.2 g of strontium isopropoxide were dissolved in 500 g of isopropyl alcohol as a solvent, and 2.15 g of water was added to the solution at a relative humidity of 4.
It was left standing at 20° C. in 0% air for 2 days.

As a result, a sol with a viscosity of 20 voids was obtained.

Next, this sol was applied onto a flat plate to obtain a thin film with a thickness of 50 gm. After drying this thin film in air for 24 hours,
By firing in air at 900 t: thickness of 30p
A thin film of copper-lanthanum-strontium ternary oxide of m was obtained.

When we measured the electrical resistance value of this thin film, it was found to be 32°
The electrical resistance value became zero at the following temperatures.

Example 2 13.0 g of copper acetylacetonate, 18.9 g of lanthanum triisopropoxide and 10.2 g of barium diisopropoxide were mixed with 500 g of isopropyl alcohol.
The wall thickness was 20 g in the same manner as in Example 1, except that it was dissolved in
A thin film of ILm copper-lanthanum-barium ternary oxide was obtained.

The electrical resistance value of this thin film became zero at a temperature below 23°.

Example 3 13.0 g of copper acetylacetonate, 16.0 g of yttrium triisopropoxide and 10.2 g of barium diisopropoxide were mixed with 500 g of isopropyl alcohol.
The wall thickness was 1 in the same manner as in Example 1 except that it was dissolved in g.
A thin film of copper-yttrium-barium ternary oxide with a thickness of 5 μm was obtained.

The electrical resistance value of this thin film became zero at temperatures below 37°.

[Effects of the Invention] According to the manufacturing method of the present invention, a superconducting oxide thin film can be manufactured more easily than conventional methods.

Claims (1)

[Claims] (1) A mixture of [A] an organic compound of copper, [B] an organic compound of a rare earth metal, and [C] an organic compound of a group II metal of the periodic table is dissolved in a solvent, and the mixture is reacted with water to form a sol, A method for producing a superconducting oxide thin film, which comprises coating or casting the generated sol onto a substrate to form a thin film, and then firing it.