JP2000211921A - Preparation of oxide superconductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare a superconductor electric wire or a large-area superconductor by diffusing or implanting Ba and O into an alloy containing at least Y or a rare earth element and Cu. SOLUTION: A powder of an oxide 7 containing Ba such as BaCO3 or BaO is placed in a high temperature-resistant vessel 12, which is then heated in oxygen or air 10 with a heater 11. In the heated state an RCu3 alloy wire 13 is slowly moved. Thereby, a Ba diffusion layer is formed on the RCu3 alloy wire 13 to provide a superconductor. A gas 14 of a metalorganic substance containing Ba in place of the oxide 7 containing the Ba such as the BaCO3 and oxygen or air 10 can be made to flow through the high temperature- resistant vessel 12 and heated to form a superconductor. Diethoxybarium, bisacetylacetonatobarium, barium naphthoate, barium octylate, etc., are cited as the metalorganic substance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an oxide superconductor.

[0002]

2. Description of the Related Art Oxide superconductors include, for example, yttrium (Y), barium (Ba), copper (Cu), As a superconductor, Y is another rare earth element neodymium (N
d), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (E)
r), thulium (Tm) or ytterbium (Yb). Hereinafter, Y or a rare earth element is represented by R
Indicated by like this Powders of R ₂ O ₃ , BaCO ₃ , CuO, etc. are converted to R, Ba, C
The mixture is mixed so that the composition ratio of u becomes R: Ba: Cu = 1: 2: 3, and a pressure is applied to produce a pellet.
Thereafter, there is a method of manufacturing by sintering the pellet in the air or oxygen atmosphere.

[0003]

The superconductor produced by the conventional method is in a ceramic form, is mechanically brittle, and it is difficult to produce a linear superconductor or a large-area superconductor. The present invention solves such drawbacks and enables the production of superconductor wires and large-area superconductors.

[0004]

[Means for Solving the Problems]

An alloy RCu ₃ containing R and Cu is produced, and thereafter, Ba and O elements are added to the alloy by means such as diffusion or ion implantation. By this method, a superconducting wire or a large-area superconductor can be manufactured.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment In the present invention, as shown in FIG. 1, a metal crucible (5) is heated by a high-frequency heater coil (4) or the like. In the metal crucible (5), R and Cu, for example, R:
Cu is mixed and put in a ratio of 1: 3. In order to prevent oxidation, an Ar gas (or a rare gas such as a He gas) (3) is flown during the heating of the metal crucible (5). When a metal crucible (5) is heated to a temperature of about 1500 ° C., R and C
u melts and becomes an alloy. The temperature of the metal crucible (5) is R
The temperature may be other than 1500 ° C. as long as the temperature is such that Cu and Cu melt. After cooling, the metal crucible (5) is taken out, and the metal crucible (5) is cut using a lathe or the like.
A rod-shaped alloy, RCu ₃ , can be taken out. Thereafter, the alloy is thinned in a lathe again into a smooth shape. Next, a straight alloy and BaCO ₃ were mixed with R: B.
a: Cu = 1: 2: 3 is mixed and pressurized to produce pellets, and the pellets are baked in air at, for example, 900 ° C. for 24 hours to obtain ceramic superconductivity. Body can be made. The critical temperature of the superconductor fabricated in this way (that is, the temperature at which the electric resistance becomes zero) is about 90K.

Second Example As shown in FIG. 2, the alloy (RCu ₃ ) (6) produced in the first example is made of quartz containing a BaCO ₃ or an oxide (7) containing Ba, such as BaO, in advance. Put in (8). Thereafter, the entire quartz container (8) is fired at atmospheric pressure or in an oxygen atmosphere, for example, at 900 ° C. for 24 hours. Oxide containing Ba such as BaCO ₃ or BaO by this heat treatment (7)
Ba diffuses into the alloy RCu ₃ (6) to form a Ba diffusion layer (9) as shown in FIG. You. The depth of the Ba diffusion layer (9) and the concentration of Ba depend on the firing time and the firing temperature. Making large area RCu ₃ alloys is a modern technology and easy. Therefore, by using the method of the present invention, a large-area superconductor can be manufactured.

Third Example A method of manufacturing a superconductor using a high temperature container (12) is shown in FIG.
Shown in A powder of an oxide (7) containing Ba, such as BaCO ₃ or BaO, is placed in a high temperature resistant container (12),
2) is heated with a heater (11) in oxygen or air (10). While heated, RCu ₃ alloy wire (13)
Is moved slowly. By doing so, as described in the second example, Ba diffusion layer (9) is formed in RCu ₃ alloy wire (13), the superconductor. Also, as a similar method, a high temperature resistant container (12) is charged with B, such as BaCO ₃ or BaO.
Instead of the oxide (7) containing a, a superconductor can also be formed by flowing a gas (14) of a metal organic material containing Ba and oxygen or air (10) and heating it. Here, as the metal organic material, diethoxybarium [Ba (O
C ₂ H ₅ ) ₂ ], bisacetylacetonatobarium [B
a (C ₅ H ₇ O ₂ ) ₂ ], barium naphthenate [Ba
_{(C n H 2n-2 O} 2) 2], barium octylate [B
a (C ₇ H ₁₅ COO) ₂ ].

Fourth Example A metal organic gas (14) containing Ba is often used in metal organic chemical vapor deposition (MOCVD). As shown in FIG. 5, the alloy (RCu ₃ ) (6) is placed on the susceptor (15), and the susceptor (15) is heated by the high-frequency heating coil (4). Then, by flowing a gas (14) and oxygen or air (10) of the metal-organic containing Ba, Ba and oxygen are diffused into a portion of the alloy _{(RCu 3) (6),} RBa 2 Cu 3 O y

Fifth Example A plate or film made of the alloy (RCu ₃ ) (6) is prepared in advance. RCu ₃ in the form of a film can be formed by a physical method such as sputtering, laser ablation, or vacuum deposition, for example.
It can be easily formed on an MgO substrate. By injecting Ba into the RCu ₃ plate or film by ion implantation or vapor deposition and performing heat treatment, a part of the RCu ₃ can be made into a superconductor.

[0010]

In the above examples, by preparing RCu ₃ alloy in advance, superconductors of various shapes can be manufactured. By using the method of the present invention, a large-area superconductor or a superconducting wire can be manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a method for producing an RCu ₃ alloy.

FIG. 2 is a cross-sectional view in which Ba is diffused into an alloy (RCu ₃ ).

FIG. 3 is a sectional view of a Ba diffusion layer.

FIG. 4 is a cross-sectional view of a method for manufacturing a superconductor using an oxide or a metal organic material containing Ba.

FIG. 5 is a cross-sectional view of a method for producing a superconductor using a metal organic material gas containing Ba.

[Explanation of symbols]

1 is an alloy of an R element and a Cu element (RCu ₃ ) 2 is a quartz tube 3 is an Ar gas (or a rare gas such as He gas) 4 is a high frequency heater coil (induction heater) 5 is a metal crucible 6 is an alloy ( RCu ₃ ) 7 is an oxide containing Ba such as BaCO ₃ or BaO 8 is a quartz vessel 9 is a Ba diffusion layer 10 is oxygen or air 11 is a heater 12 is a high temperature vessel 13 is an RCu ₃ alloy wire 14 is a metal containing Ba Organic gas 15 is the susceptor

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Claims (7)

[Claims] An alloy containing at least a yttrium (Y) element or a rare earth element and a copper (Cu) element is manufactured by diffusing or implanting a barium (Ba) element and an oxygen (O) element. To manufacture superconductors. 2. A method for producing a superconductor according to claim 1, wherein the composition ratio of Y element or rare earth element to Cu is about 1: 3. 3. The method for producing a superconductor according to claim 1, wherein the raw material used for diffusing Ba is an oxide containing Ba as a constituent element. 4. An oxide according to claim 3, wherein the oxide is either BaCO ₃ or BaO, and the oxide and the alloy according to claim 1 or 2 are brought into contact with each other and heated. How to make the body. 5. The method according to claim 1, wherein the Ba element according to claim 1 is diffused or implanted by any one of a vacuum evaporation method, a sputtering method, an ion implantation method, a laser ablation method, and a molecular beam evaporation method. To manufacture superconductors. 6. A method for producing a superconductor according to claim 1, wherein a Ba-containing metal organic gas is used to diffuse the Ba element. 7. The metal organic substance according to claim 6, wherein the metal organic substance is diethoxybarium [Ba (OC ₂ H ₅ ) ₂ ], bisacetylacetonite barium [Ba (C ₅ H ₇ O ₂ ) ₂ ], barium naphthenate [ _{Ba (C n H 2n-2} O 2) 2], a method for manufacturing a superconductor, characterized in that barium octylate _{[Ba (C 7 H 15 COO} ) 2], is either.