JPH026329A - Superconducting material composition - Google Patents

Abstract

PURPOSE:To provide a novel superconducting material composition capable of realizing superconducting state at a temperature of liquid nitrogen or above by introducing Tl having a specific atomic ratio into a rare earth element- Ba-Cu-O based superconducting material. CONSTITUTION:The aimed superconducting material composition having a composition expressed by the formula (Ln is Y, Gd, Dy, Ho, Er, La, Nd, Sm, Eu or Yb; 0.8<x<1.2; 0.8<y<1.2; 0.5<z<1.5; w is atom number of oxygen satisfying required valence of other element). As an embodied example of production of the superconducting material composition, an oxide-mixing and -baking method carried out by mixing yttrium oxide with barium carbonate, thallium oxide and copper oxide at a prescribed amount, heating the mixture at about 700-950 deg.C and subjecting the mixture to a solid reacting is given. The obtained superconducting material has a critical temperature of about 90K.

Description

[Detailed description of the invention] (1) Industrial application fields The present invention relates to superconducting material compositions.

(2) Conventional technology Although superconducting materials are expected to have a wide range of applications in industries such as magnetic levitation IJ near motor cars, current practical materials have low critical temperatures and are limited to use under liquid helium conditions. The reality is that K has not met those expectations. For this reason, the emergence of superconducting materials that can be used at liquid nitrogen temperatures is strongly desired. Recently, La.

Oxides made of Ba and Cu, oxides made of Y, Ba, and Cu, oxides made of Bir Sr, Ca, and Cu, oxides made of Tλ, Ba, Ca, Cu, etc. provide superconductivity at high temperatures. It is attracting attention as a composition. The present invention meets expectations as a new high-temperature superconducting material that can be used at liquid nitrogen temperatures.

(3) Structure of the invention, that is, the present invention is based on the general formula Lnz Bay 'l'i□C
u30w (where Ln is yttrium, gadolinium,
Disprosium, holmium, erbium, lanthanum,
neodymium, samarium, europium.

represents ytterbium, Ba represents barium, T
1 represents thallium, Cu represents copper, and 0 represents oxygen. Also, x, y, and z are 0.8 < X <1.2.0.8<7<1 when the atomic ratio of steel is fixed at 3.
．． In the range of 2.0.5<Z<1.5, w represents the number of oxygen atoms that satisfies the required valence of other elements. ) is a superconducting material composition represented by

(4) Detailed Description of the Invention The composition of the present invention is a novel superconducting material composition that has a completely different structure from conventional superconducting materials and can achieve a superconducting state at temperatures above liquid nitrogen temperature. The preparation method can be selected depending on the use, and examples include yttrium oxide, barium carbonate, thallium oxide,
This is an oxide mixing firing method in which a predetermined amount of oxidized steel is mixed and a solid phase reaction is performed by heating at about 700°C to 950°C.

In addition, various coprecipitation methods, precipitation mixing methods, salt decomposition methods, etc. known to those skilled in the art of producing oxide compositions can be used. Therefore, as raw materials for each element, oxides, nitrates, organic acid salts, metal alkoxides, etc. can be used. Depending on the application, a CVD method, a sputtering method, a vapor deposition method, etc. are selected. Therefore, as raw materials, in addition to individual elements, metals, etc., raw materials suitable for the preparation method can be selected.

(5) Examples The present invention will be explained below with reference to Examples.

Example 1 Commercially available special grade reagent Y2O32,26P, BaCO33,9
5f, TR2Q33.95? , Cu0 4.77
f was weighed out, mixed for 1 hour in a rice cooker, and then calcined at 920°C for 10 hours. After being left to cool, the fired powder was lysed, formed into tablets, and then fired again in an electric furnace at 920°C for 10 hours. When the fired product was measured using the four-terminal method, the temperature at which the resistance became completely zero was 90°C. Magnetic susceptibility is also 9
It showed diamagnetic properties from 7K. The specific resistance of the fired product was 3.28 x 10-''Ω. The X-ray diffraction results of the fired product showed that the structure was different from conventional superconducting materials.

Patent applicant: Mitsubishi Yuka Co., Ltd. Agent: Patent Attorney Masahisa Nagatani Agent Patent Attorney Takaya Yamamoto

Claims (1)

[Claims] 1. General formula Ln_xBa_yTl_zCu_3O_w(
In the formula, Ln represents yttrium, gadolinium, dysprosium, holmium, erbium, lanthanum, neodymium, samarium, europium, ytterbium, Ba represents barium, Tl represents thallium,
Cu represents copper and O represents oxygen. Also, x, y,
z is 0.8<x<1 when the atomic ratio of copper is fixed at 3.
．． 2, 0.8<y<1.2, 0.5<z<1.5, and w represents the number of oxygen atoms satisfying the required valence of other elements. ) A superconducting material composition represented by