JPH01219005A - Method for creating oxide superconductor 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 (Field of Industrial Application) The present invention relates to a method for producing an oxide superconductor thin film by a solution method.

(Prior art) In recent years, Y-Ba Cu-01/, and Lm-M-C
u-OR (where H is Sr, Ca, Ba), various oxide-based superconductors that exhibit superconductivity at high temperatures have been developed, but when these are used for printed circuit boards and semiconductors, thin films It is necessary to

Conventionally, this thin film has been created by (1) sputtering a metal oxide onto a substrate, (2) screen-printing a metal oxide powder paste onto a substrate and then baking it, or (3) mixing the metal oxide powder. This is done by dispersing it in a solution and applying it.

(Problems to be Solved by the Invention) However, in the method (1), since the raw material and the thin film often have different compositions, it is difficult to keep the composition constant;
Method (2) cannot make the surface smooth because the amount of solvent is small, and method (3) ends with smoothing the surface, but the specific gravity of the metal oxide powder differs depending on the type of metal. Therefore, there was a problem that those with a high specific gravity settled during coating, and it was not possible to prepare a product with a uniform composition.

Therefore, the present invention provides a method for forming a thin film having a uniform composition in the method (3) for forming a thin film using a solution method.

(Means for Solving the Problems) The present inventors have achieved a uniform composition using a solution method! As a result of various studies to develop a method for creating a film, we found that by applying a solution of an organic metal salt dissolved in an organic solvent and simultaneously removing the organic component of the organic metal salt and oxidizing the metal component through thermal decomposition, metal oxidation was achieved. I developed a method to make things *a.

That is, in the present invention, one or more of alkoxides, acetylacetonate metal salts, and octylate metal salts are blended so that the metal component thereof is the metal of the superconductor-constituting oxide and the metal molar ratio. After applying the dissolved organic solvent solution to the support, 780 to 1
It is heated to 000°C to form a metal oxide thin film.

Alkoxides, acetylacetonate metal salts, and octylate metal salts have the property of being easily soluble in organic solvents and easily thermally decomposed by heating to form metal oxides. Therefore, by applying the organic solvent solution, evaporating the organic solvent, and then thermally decomposing it, the organic component is removed and the metal component is also oxidized, making it possible to create a metal oxide thin film.

The alkoxide may be an alkoxide of a lower alcohol such as methoxide, ethoxide, aboxoxide or butoxide.

The organic solvent for dissolving the organometallic salt is not particularly limited as long as it can dissolve the organometallic salt, but a low boiling point is preferred in order to evaporate the organic solvent before thermal decomposition.

The organic solvent solution of the above-mentioned organometallic salt has a viscosity as low as water, so if it is not possible to increase the amount applied in one application even if the concentration is increased, apply it and dry it before thermal decomposition. Repeat and increase the amount of application.

Thermal decomposition is carried out at 780 to 1000° C. after drying the applied organic solvent solution and evaporating the organic solvent.

If the temperature is less than 780°C, complete thermal decomposition will not occur and organic components will not be removed, and if it exceeds 1000°C, the metal oxide may melt if it has a low melting point.

To create a thin film of an oxide superconductor by applying an organic solvent solution of this alkoxide, acetylacetonate metal salt, and octylate metal salt, it is necessary to For example, in a hos BaO-CuO superconductor, the oxides exhibiting superconductivity are blended in a metal equivalent molar ratio of Y:Ba:Cu=1:2:3. If any, organic metal salts are blended so that the metal components are in such proportions.This blending may be carried out with either alkoxide, 7-cetylacetonate metal salt, or octylate metal salt alone, or in combination. It may also be done by

Oxides that exhibit superconductivity and their formulations will continue to be developed in the future, but organic metal salts such as those mentioned above can be synthesized with most metals, including rare earth elements, and have the same properties. , even if the types of superconductor-constituting oxides increase in the future, it will be necessary to synthesize them accordingly6.For example, in the case of rare earth elements, in addition to Y, La, Ce5Nd, Ps+
, S theory, Eu%Gd5Dy, Ho, Er, 7m%Y
Alkoxides such as b5Lu, acetylacetonate salts, and octylate salts can also be synthesized.

(Example) Example I Seven cetyl acetonate salts of Y, Ba, and Cu were mixed so that the metal component molar ratio was Y:Ba:Cu=1:2:3, and then dissolved in chloroform. A solution having a concentration of 0.05 wt% was prepared. Thereafter, this solution was applied onto an MgO substrate by a dipping method, and after drying, it was placed in an electric furnace in an air atmosphere and heated at 950° C. for 12 hours.

After heating, it was slowly cooled to 400°C over 10 hours, and then allowed to cool naturally.

The obtained thin film oxides were Y2O5, B as in Example 1.
aO1CuO was confirmed, and the metal ratio of the oxide was Y:Ba:Cu=1:2:3 in molar ratio.

Example 2 Octylate salts of Y, Ba, and Cu were mixed so that the metal component molar ratio was Y:Ba:Cu=1:2:3, and then dissolved in toluene to give a concentration of 0.1 wt.
A thin film was prepared in the same manner as in Example 1 using this solution. Note that a 7-layer plate was used as the substrate for coating.

The oxides of the obtained thin film were confirmed to be Y, 05, BaO1CuO, and the metal ratio of the oxides was Y:Ba:C in molar ratio.
u=1:2:3.

Example 3 After mixing Y, Da, and Cu toxides such that the metal component molar ratio was Y:Ba:Cu=1:2:3.

A solution having a concentration of 0.08 wt% was prepared by dissolving it in Improper Tool, and a thin film was prepared in the same manner as in Example 1 using this solution.

The oxides of the obtained thin film were confirmed to be Y, 03.8aO, and CuO, and the metal ratio of the oxides was Y:Ba:C in molar ratio.
u=1:2:3.

(Effects of the Invention) As described above, since the present invention applies an organic metal salt solution to a substrate and converts it into an oxide through thermal decomposition, there is no possibility that metal components will settle due to differences in specific gravity. Of uniform composition? You can create 1lIK.

Claims (1)

[Claims] An organic solvent solution in which one or more of alkoxides, acetylacetonate metal salts, and octylate metal salts are mixed and dissolved so that the metal component has the same molar ratio as the metal of the superconductor-constituting oxide. 1. A method for producing an oxide-based superconductor thin film, which comprises applying the film onto a support and then heating the film to 780 to 1000°C in an oxygen atmosphere to form a metal oxide thin film.