JP2003277188A - Large superconducting intermediates, large superconductors and methods of making them - Google Patents

Abstract

(57) [PROBLEMS] A large superconducting bulk material having a large area grown by using a plurality of seed crystals, and a large superconducting bulk material with a structural support compounded with a high-strength ceramic material; The manufacturing method is provided. SOLUTION: A large superconducting structure characterized by a structure in which at least three superconducting layers having different peritectic temperatures are three-dimensionally stacked in the order of Tp, and a polycrystalline oxide ceramic is fixed to the lower surface of the layer having the lowest Tp. An intermediate, a large superconductor using the intermediate, and a method for producing the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large-scale material for rare earth oxide superconductor having a critical temperature of 90 K class and a method for producing the same.

[0002]

_2. Description of the Related Art Conventionally, as a method for producing a REBa ₂ Cu ₃ O _x type superconducting bulk material, which is the object of the present invention, Quench and Melt Gr
owth method (patent registration 1869884 and patent registration 2556401)
And a melting method represented by This method
Temporarily raise the temperature to a temperature range in which the RE ₂ BaCuO ₅ phase or RE ₄ Ba ₂ Cu ₂ O ₁₀ phase and the liquid phase containing Ba-Cu-O as the main component coexist, and then REBa ₂
This is a method in which a large bulk material is obtained by cooling to just above the peritectic temperature at which Cu ₃ O _x is formed and gradually cooling from that temperature to grow crystals, control nucleation and crystal orientation. By using this manufacturing method, it is possible to obtain a relatively large-sized superconducting material having a high critical current density (one of the superconducting properties and the current density that can be passed per unit cross-sectional area).

On the other hand, in the method of using a plurality of seed crystals for producing a large-sized material and growing the crystals from each seed crystal, the region to be grown from each seed crystal becomes narrow, so that the crystal growth occurs in a relatively short period of time. Has a feature that can be realized. In particular, JP 2
The method of the 001-322897 publication realizes the removal of "segregated phases that are rejected between the regions grown from each seed crystal" which has been a problem in the conventional method using a plurality of seed crystals. As a result, the superconducting properties between the regions grown from the respective seed crystals are improved, and more uniform superconducting properties are obtained as a whole.

By using the above method, it is possible to manufacture a sample having a wider area and uniform superconducting properties. However, the large size causes cracks in the superconducting material during processing into a desired shape. There was a problem such as being easy to enter.
The material strength of RE-Ba-Cu-O superconducting material itself is not the strongest among ceramic materials, and it is also known to add Ag element to improve the strength. Strength improvement was not sufficient.

On the other hand, a combination with another material having high strength, that is, a composite material of a structural support material having high strength and a superconducting material can be considered. In order to avoid cracks and the like that occur during processing into the desired shape as described above, it is necessary to form a composite with a structural support material with high strength immediately after crystal growth. Therefore, the superconducting precursor during crystal growth treatment is required. It is possible to consider a method of simultaneously charging and the structural support material. However, in this case, the RE-Ba-Cu-O superconducting material is in a high temperature state of around 1000 ° C. during the above crystal growth, and since Ba element and Cu element oxides exist as a liquid phase, high reactivity and simple In such combinations, there was a problem that the superconducting transition temperature and the critical current density were lowered by reacting with the structure supporting material and diffusing the constituent elements of the structure supporting material into the RE-Ba-Cu-O superconducting material.

[0006]

DISCLOSURE OF THE INVENTION The present invention is to grow a crystal using a plurality of seed crystals, and as a result, in a large-sized superconducting bulk material having a wider area and uniform superconducting properties, the superconducting transition temperature and the critical current density. It is an object of the present invention to provide a large-sized superconducting bulk material with a structural support material that is composited with a ceramic material having high strength without deteriorating the superconducting characteristics such as the above, and a manufacturing method thereof.

[0007]

In order to solve the above-mentioned problems, the present invention comprises three or more kinds of oxide superconductors having different 123 phase peritectic temperatures (Tp), and a polycrystalline oxide ceramics. Partly reacts with the oxide superconducting layer with the lowest Tp, and even if they are firmly fixed, an oxide superconducting layer with an intermediate Tp (lower than the highest Tp and higher than the lowest Tp) The constituent elements of the structure supporting material do not diffuse, and their superconducting properties (superconducting transition temperature and critical current density) are not affected. By disposing the superconducting layer with the lowest Tp in the structure, a large-scale superconducting bulk material with a structural support material that is composited with a high-strength ceramic material can be obtained without degrading the superconducting properties such as superconducting transition temperature and critical current density. It is a measure taken.

The first feature of the present invention is that REBa ₂ Cu ₃ O _x (RE is Y
One or a combination of rare earth elements containing a) superconducting intermediate of 123 phase having a structure in which a non-superconducting phase is finely dispersed in a REBa ₂ Cu ₃ O _x phase (123 phase) (peritectic temperature ( Tp)
Has a structure in which a plurality of oxide superconducting layers different from each other are three-dimensionally stacked in the order of Tp, and two or more seed crystals are placed on the oxide superconducting layer having the highest Tp, A large-sized superconducting intermediate characterized in that the high Tp oxide superconducting layer contains a repulsive phase, and the polycrystalline oxide ceramics is fixed to the lower surface of the oxide superconducting layer having the lowest Tp.

The non-superconducting phase in the present invention is a matrix phase.
REBa ₂ Cu ₃ O _x (123) finely dispersed RE ₂ BaCuO ₅ phase or R
E ₄ Ba ₂ Cu ₂ O ₁₀ Refers to the phase. In addition, the REBa ₂ Cu ₃ O _x phase (12
123 phase with a different peritectic temperature (Tp) of 3 phases means that the peritectic temperature (Tp) of the 123 phase is changed by changing the RE composition, and an oxide superconductor composed of composition powders with different Tp Refers to. In addition, the three-dimensionally laminated structure means a laminated structure, a concentric circular structure, or a combination thereof.

The second feature of the present invention is that the average linear expansion coefficient of polycrystalline oxide ceramics from room temperature to 800 ° C. is 10 pp.
The above-mentioned first featured in that it is not less than m / ℃ and not more than 20 ppm / ℃
Is a large-scale superconducting intermediate. The third feature of the present invention is the above-mentioned first or second large-sized superconducting intermediate, characterized in that the main component of the polycrystalline oxide ceramics is a MgO polycrystalline material. The main component being MgO polycrystalline material means a material in which 90% or more of MgO is present in the polycrystalline oxide ceramics.

A fourth feature of the present invention is the large-scale superconducting intermediate body according to any one of the first to third features, wherein the oxide superconducting layer having the lowest Tp contains Yb element. The fifth feature of the present invention is that the laminate has 1 to 30% by mass.
At least one oxide superconducting layer containing Ag element
The large-scale superconducting intermediate body according to any one of the first to fourth aspects, which is formed by stacking layers.

A sixth feature of the present invention is that the laminate has
001 to 2.0 mass% Rh element, 0.05 to 5.0 mass% Pt element,
Alternatively, the large-scale superconducting intermediate body according to any one of the first to fifth aspects, wherein at least one oxide superconducting layer containing at least one element of 0.05 to 10.0 mass% Ce element is laminated. A seventh feature of the present invention is that the oxide superconducting layer containing the seed crystal and the repulsion phase of the large-sized superconducting intermediate described in any one of the above 1 to 6 is cut off and subjected to oxygen enrichment heat treatment. Is a large-scale superconductor.

The eighth feature of the present invention is that REBa ₂ Cu ₃ O _x (RE is Y
One or a combination of rare earth elements including) A superconducting material that composes a RE superconductor, Ba and Cu components is heated, and the maximum temperature is the REBa ₂ Cu ₃ O _x phase (123 phase) of the compact. It is a method of producing an oxide superconducting intermediate in which a non-superconducting phase is finely dispersed in the 123 phase by cooling after the peritectic temperature (Tp) or higher of Is a raw material molding laminated body in which at least three layers are three-dimensionally laminated in the order of Tp, and is the lowest on the polycrystalline oxide ceramics.
It is placed so that the raw material forming laminate having Tp is in contact with the raw material forming laminate, and a plurality of seed crystals are placed on the raw material forming laminate having the highest Tp, and then the raw material forming laminate is heat treated. It is a method for producing a characteristic oxide superconducting intermediate.

The ninth feature of the present invention is that the average linear expansion coefficient of the polycrystalline oxide ceramics from room temperature to 800 ° C.
The eighth method for producing a large-sized superconducting intermediate is characterized in that it is 10 ppm / ° C or more and 20 ppm / ° C or less. A tenth feature of the present invention is the eighth or ninth large-sized superconducting intermediate producing method, wherein the main component of the polycrystalline oxide ceramics is a MgO polycrystalline material.

The eleventh feature of the present invention is that the lowest Tp
The method for producing a large-sized superconducting intermediate according to any one of the above 8th to 10th aspects, characterized in that the oxide superconducting raw material molded body containing Yb element is included. A twelfth feature of the present invention is that the laminated body is laminated with at least one layer of an oxide superconducting raw material molded body containing 1 to 30 mass% of Ag element.
An eleventh method for producing a large-sized superconducting intermediate.

A thirteenth feature of the present invention is that the raw material molding laminate comprises 0.001 to 2.0% by mass of Rh element and 0.05 to 5.0% by mass.
At least one raw material compact containing at least one of Pt element or 0.05 to 10.0 mass% Ce element.
The method for producing a large-sized superconducting intermediate body according to any one of the eighth to twelfth aspects, wherein the layers are laminated.

The fourteenth feature of the present invention is the above eighth to thirteenth features.
A method for producing a large-sized superconductor, comprising removing an oxide superconductor layer containing a seed crystal and a repulsion phase from the large-sized superconducting intermediate obtained by the method described above, and then performing an oxygen enrichment treatment.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention grows a crystal using a plurality of seed crystals, and as a result, in a large-sized superconducting bulk material having a wider area and uniform superconducting characteristics, the superconducting transition temperature, the critical current density, etc. Is a large-sized superconducting bulk material with a structural support material, which is composited with a ceramic material having high strength without deteriorating the superconducting characteristics and the manufacturing method thereof. The point of the present invention is to develop the method of Japanese Patent Laid-Open No. 2001-322897 and use a superconducting layer having the lowest Tp between a large-sized superconducting bulk material and a structure supporting material. Hereinafter, this point will be described in detail.

When the raw material molding laminate in JP-A-2001-322897 is placed on the structure supporting material and the crystal growth treatment is performed, it is exposed to a high temperature of about 1000 ° C. during crystal growth, A reaction occurs at the interface between the superconducting layer and the structure supporting material, and as a result, an impurity element is mixed in the superconducting layer, which deteriorates superconducting properties such as superconducting transition temperature and critical current density.

On the other hand, in the method of the present invention, as shown in FIG. 1, an oxide superconductor composed of at least three layers having different Tp's is used, but the layer having the lowest Tp is set to an appropriate thickness (100).
μm or more is preferable), so that even if the layer having the lowest Tp reacts with the structural support material, the layer having the lowest Tp
Impurity element incorporation in layers with a lower (higher than the lowest Tp) Tp can be greatly reduced. That is, the layer having the lowest Tp is used as a layer for preventing the impurity element from being mixed into the layer having the intermediate Tp. In addition, since the layer having the intermediate Tp plays a role as a superconducting material, the layer having the lowest Tp does not necessarily have to be crystal-grown, and may be polycrystallized. Further, from the viewpoint of adhesion to the structural support material, it is preferable that the layer having the lowest Tp has a high density. For example, as a raw material molding laminate, one obtained by integrally molding three layers of a layer having the lowest Tp, a layer having an intermediate Tp, and a layer having the highest Tp, and then applying hydrostatic pressure,
By placing the layer on the structure supporting material and performing the crystal growth treatment, the layer having the lowest Tp after crystal growth has a high density and can be adhered to the structure supporting material.

On the other hand, since the RE-Ba-Cu-O superconducting material has a large coefficient of thermal expansion (when RE is Y, around 13 ppm / ° C in the ab axis direction), the structural support materials also have substantially the same thermal expansion coefficient. Must be a coefficient. When a structural support material with a coefficient of thermal expansion significantly different from that of the superconducting material is used,
Upon cooling from a high temperature of about 00 ° C. to 1100 ° C. to room temperature, tensile stress or compressive stress due to the difference in heat shrinkage at the interface acts on the superconducting material and causes cracks such as cracks.
The superconducting material has higher strength (eg, three-point bending strength) under compression than under tension. Therefore, even if the coefficient of thermal expansion of the structural support material is somewhat larger than the coefficient of thermal expansion of the superconducting material, compressive stress acts on the superconducting material during cooling, so that cracking or the like is unlikely to occur. For this reason, the temperature range from the main temperature range (room temperature (20 ° C)) where heat shrinkage works
(00 ° C), the coefficient of linear expansion is limited to the range of 10ppm / ° C to 20ppm / ° C. Examples of such a structure supporting material include MgO and stabilized ZrO ₂ . In particular, the dense MgO polycrystalline material is inexpensive and light, and has a thermal expansion coefficient of about 13 ppm / ° C, which is RE-Ba-Cu.
-O Excellent in having a value close to that of superconducting materials, making it suitable as a structural support material.

The stress generated by thermal contraction is the lowest Tp
It is the lowest because the oxide superconducting layer containing
By using Yb element (Tp = 910 ± 10 ℃) for the oxide superconducting layer having Tp, Tp is effectively kept low, and the temperature at which it is fixed to the structural support material is also lowered. It is possible to suppress the generated stress due to.

Furthermore, by including Ag element in the superconducting material, the strength of the oxide superconductor itself can be improved according to the added amount, and cracks and the like can be suppressed. Ag element addition amount is 1 ~
Within the range of 30% by mass, the effect of improving strength can be exhibited. Further, during heat treatment, Ag element easily diffuses in each oxide superconducting layer, and Tp also changes depending on the concentration of Ag element, so to obtain stable crystal growth, the amount of Ag element added to each oxide superconducting layer is It is desirable that each layer has the same mass%.

The addition of Rh, Pt, and Ce elements will be described below. These elements are the parent phase REBa ₂ Cu ₃ O _x.
The RE ₂ BaCuO ₅ phase or the RE ₄ Ba ₂ Cu ₂ O ₁₀ phase is finely dispersed in the (123) phase, which has the effect of improving the critical current density, which is one of the superconducting properties. The amount of addition is respectively the RE ₂ BaCuO ₅ phase or
From the concentration at which RE ₄ Ba ₂ Cu ₂ O ₁₀ phase refinement begins to appear,
The concentration is limited so that the effect will not be improved even if it is added more than this, which allows a larger current density to flow in the superconductor. That is, the amount at which the effect of addition is obtained is
The Rh element is 0.001 to 2.0 mass%, the Pt element is 0.05 to 5.0 mass%, and the Ce element is 0.05 to 10.0 mass%. Also, considering the diffusion of each element, it is desirable that the amount of element added to each oxide superconducting layer be the same mass% for each layer, but the layer with the lowest Tp does not necessarily have to undergo crystal growth. Alternatively, an inexpensive Ce element can be used only in the layer.

Since a plurality of seed crystals are used in this method, a layer having the highest Tp has a Ba-Cu-O compound, a Cu-O compound, or segregation between crystal growth regions grown from various crystals. The non-superconducting phases such as the RE ₂ BaCuO ₅ phase or the RE ₄ Ba ₂ Cu ₂ O ₁₀ phase that have been removed are excluded. This non-superconducting layer remarkably hinders superconducting coupling between crystal growth regions grown from various crystals, and the superconducting current flowing through the regions is also significantly reduced. Therefore, the superconducting layer in which the above-mentioned repulsion phase precipitates after the crystal growth treatment is cut off in advance, and then the oxygen enrichment treatment is applied to the superconducting intermediate to significantly increase the superconducting current flowing between the crystal growth regions grown from various crystals. It is possible to obtain a material having more uniform superconducting properties without any significant decrease.

The thickness of each superconducting layer will be described below. After crystal growth, at high temperature during crystal growth,
Diffusion of superconducting layers with different Tp occurs. Therefore, in some of the diffused regions, regions having the same Tp occur. Therefore, with respect to the lower limit of the thickness, a thickness that can remain as a superconducting layer having a different Tp is preferable. For example, when the Tp is changed by changing the RE component, the lower limit of each superconducting layer is preferably about 100 μm. Further, as the ratio of the thickness of each superconducting layer, the total thickness of the superconducting layers to be excised is considered in consideration of excising the region where the repulsion phase finally occurs as in claim 7 or 14 of the present invention. It is preferable that the total thickness of the superconducting layer remaining after cutting is not exceeded.

[0027]

[Example] (Example 1) Dy ₂ O ₃ , BaO ₂ , and CuO raw material powders were mixed so that the molar ratio (Dy: Ba: Cu) of each element was (13:17:24). Then, 0.5 mass% of Pt element was further added to this mixed powder to prepare a mixed raw material powder. This was calcined at 900 ° C. in an oxygen stream. This is designated as Powder 1-A. Also, Dy
₂ O ₃ , Ho ₂ O ₃ , BaO ₂ and CuO raw material powders, the molar ratio of each element
Mix so that (Dy: Ho: Ba: Cu) becomes (6.5: 6.5: 17: 24),
Furthermore, 0.5 mass% of Pt element was added to this mixed powder to prepare a mixed raw material powder. This was calcined at 900 ° C. in an oxygen stream. This is designated as Powder 1-B. Furthermore, Yb ₂ O ₃ and BaO
_2, the molar ratio of the raw materials powders each element CuO (Yb: Ba: Cu) is (1
3:17:24) and then add 1.0 to this mixed powder.
Mass% Ce element was added as an oxide to prepare a mixed raw material powder. This was calcined at 850 ° C. in an oxygen stream.
This is designated as Powder 1-C. Furthermore, each raw material powder of Sm ₂ O ₃ , BaO ₂ , and CuO was mixed so that the molar ratio (Sm: Ba: Cu) of each element was (13:17:24), and 1.0 mass of this mixed powder was further added. % Ce
An element was added as an oxide to prepare a mixed raw material powder. This was calcined at 920 ° C in an oxygen stream. This is designated as Powder 1-D.

Next, using the powders 1-A, 1-B, and 1-C, a molded body was prepared as shown in FIG. 2-a, and the columnar shape had a diameter of 54 mm and a thickness of 20 mm at ² ton / cm ^2. A precursor was prepared. A 3 mm square and 1 mm thick Sm _0.7 Nd _0.3 Ba ₂ Cu ₃ O _x system superconducting seed crystal is placed on this precursor as shown in FIG. 2-b, and the powder 1-
D was laid out in 60 mm square and about 8 mm thick, and a 50 mm square 50 mm square dense 4 mm thick MgO plate with a purity of 99% was placed on it as a structural support material, and the columnar precursor was placed on it. . This was heated to 1045 ° C in the atmosphere in 10 hours, kept for 4 hours, and then cooled to 1010 ° C in 2 hours. After that, 100 up to 980 ℃
The mixture was gradually cooled over a period of time, crystal growth was performed, and the mixture was cooled down to room temperature over a period of 24 hours. By this heat treatment, it was confirmed that the diameter of the columnar precursor contracted to 46 mm and was fixed to the 50 mm square structural support material.

No cracks such as cracks were found in the obtained superconducting bulk material. After that, the layer composed of the seed crystal and the powder 1-A was cut off, heated in an oxygen stream to 450 ° C in 24 hours, gradually cooled to 400 ° C in 100 hours, and then allowed to reach room temperature in 10 hours. The temperature dropped. When the superconducting bulk material that had been subjected to the oxygen enrichment treatment was cooled in a magnetic field at 77K and the external magnetic field was removed, the supplemental magnetic flux density was measured,
Good values up to 0.8T were obtained.

(Example 2) Raw material powders of Gd ₂ O ₃ , BaO ₂ and CuO were mixed so that the molar ratio (Gd: Ba: Cu) of each element was (12:18:26), Further, 0.5 mass% of Pt element was added to this mixed powder to prepare a mixed raw material powder. 10% by mass of Ag ₂ O powder was added to the powder obtained by calcining this at 900 ° C. in an oxygen stream. This is designated as Powder 2-A. Also, Dy ₂ O ₃ , G
The raw material powders of d ₂ O ₃ , BaO ₂ and CuO were mixed in the molar ratio (Dy: G
d: Ba: Cu) was mixed to be (6: 6: 18: 26), and 0.5 mass% of Pt element was further added to this mixed powder to prepare a mixed raw material powder. 10% by mass of Ag ₂ O powder was added to the powder obtained by calcining this at 900 ° C. in an oxygen stream. This is designated as Powder 2-B. Further, Yb ₂ O ₃ , BaO ₂ , CuO raw material powders were mixed so that the molar ratio of each element (Yb: Ba: Cu) was (12:18:26), and further 0.5 to this mixed powder. Mass% Pt element was added as an oxide to prepare a mixed raw material powder. The powder obtained by calcining this in an oxygen stream at 850 ° C
Mass% Ag ₂ O powder was added. RE of this and powder 2-B
The powder obtained by weighing and mixing the elements so that the molar ratio of the elements is the same is designated as 2-C.

Next, using the powder 2-A, 2-B, 2-C, to prepare a molded body as in Fig. 3-a, in 2 ton / cm ^2, a vertical
A prismatic precursor having a size of 27 mm, a width of 77 mm and a thickness of 15 mm was produced. A 3 mm square and 1 mm thick Sm _0.7 Nd _0.3 Ba ₂ Cu ₃ O _x system superconducting seed crystal is placed in this precursor as shown in Fig. 3-b. Alumina powder is 60 mm square and 8 mm thick. A MgO plate having a length of 30 mm, a width of 80 mm and a thickness of 4 mm and a dense and 99% purity was placed on the surface as a structural support material, and the prismatic precursor was placed thereon. This was heated to 1058 ° C in the atmosphere in 10 hours, kept for 2 hours, and then cooled to 1010 ° C in 2 hours.
Then, for crystal growth, it was gradually cooled to 980 ° C over 100 hours, cooled to 870 ° C over 50 hours, and cooled to room temperature over 24 hours.

No cracks such as cracks were found in the obtained superconducting bulk material. After that, the layer composed of the seed crystal and the powder 2-A was cut out, the temperature was raised to 400 ° C. in an oxygen stream for 24 hours, maintained at 400 ° C. for 100 hours, and then lowered to room temperature over 10 hours. The superconducting bulk material that had been subjected to the above-mentioned oxygen enrichment treatment was cooled in a magnetic field at 77K, the external magnetic field was removed, and the supplemental magnetic flux density was measured.
A good value of was obtained.

[0033]

According to the present invention, it is possible to realize a large-sized superconducting bulk material with a structural support material, which has a large area and uniform superconducting properties, and is composited with a ceramic material having high strength that does not easily cause cracks such as cracks. was gotten.

[Brief description of drawings]

FIG. 1 is an example of a configuration diagram of the present invention.

2 is a schematic diagram of a superconductor used in Example 1. FIG. (A) Schematic view of the molded body used in Example 1 (B) Layout of seed crystals used in Example 1

FIG. 3 is a schematic diagram of a superconductor used in Example 2. (A) Schematic view of the molded body used in Example 2 (B) Layout of seed crystals used in Example 2

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Claims (14)

[Claims] 1. REBa ₂ Cu ₃ O _x (RE is a rare earth element containing Y)
Type or combination thereof) system superconducting intermediate, REB
At least three oxide superconductor layers with different peritectic temperatures (Tp) of the 123 phase having a structure in which the non-superconducting phase is finely dispersed in the a ₂ Cu ₃ O _x phase (123 phase) are at least three-dimensionally arranged in the order of Tp. It has a structure in which three layers are stacked, and 2 is formed on the oxide superconducting layer with the highest Tp.
One or more seed crystals are placed, at least the high Tp oxide superconducting layer contains a repulsive phase, and the polycrystalline oxide ceramics is characterized by being fixed to the lower surface of the oxide superconducting layer having the lowest Tp. Large superconducting intermediate. 2. The average linear expansion coefficient of the polycrystalline oxide ceramics from room temperature to 800 ° C. is 10 ppm / ° C. or more and 20 ppm / ° C.
The large-sized superconducting intermediate body according to claim 1, wherein: 3. The large-sized superconducting intermediate body according to claim 1, wherein the main component of the polycrystalline oxide ceramics is MgO polycrystalline material. 4. The large-scale superconducting intermediate according to claim 1, wherein the oxide superconducting layer having the lowest Tp contains Yb element. 5. The large-sized product according to claim 1, wherein the laminate comprises at least one oxide superconductor layer containing 1 to 30% by mass of Ag element. Superconducting intermediate. 6. The oxide superconducting material, wherein the laminated body contains at least one element of 0.001 to 2.0 mass% Rh element, 0.05 to 5.0 mass% Pt element, or 0.05 to 10.0 mass% Ce element. The large-sized superconducting intermediate body according to claim 1, wherein at least one body layer is laminated. 7. The oxide superconducting layer containing the seed crystal and the repulsion phase of the large-sized superconducting intermediate according to claim 1, is excised and then subjected to oxygen enrichment heat treatment. And a large superconductor. 8. RE, Ba and C constituting a REBa ₂ Cu ₃ O _x (one kind of rare earth element including Y or combination thereof) type superconductor.
After heating the raw material molded body containing the u component, the maximum temperature after the peritectic temperature (Tp) of the REBa ₂ Cu ₃ O _x phase (123 phase) of the molded body,
A method for producing an oxide superconducting intermediate in which a non-superconducting phase is finely dispersed in the 123 phase by cooling,
A raw material molded body in which the Tp of different phases is three-dimensionally stacked in the order of Tp is formed as a raw material molded laminated body, and the raw material molded body having the lowest Tp is placed on the polycrystalline oxide ceramic so as to be in contact therewith. Then, a method for producing a large-sized superconducting intermediate characterized by placing a plurality of seed crystals on the raw material molding laminate having the highest Tp, and then heat treating the raw material molding laminate. 9. The average linear expansion coefficient of the polycrystalline oxide ceramics from room temperature to 800 ° C. is 10 ppm / ° C. or more and 20 ppm / ° C. or more.
The method for producing a large-sized superconducting intermediate according to claim 8, wherein: 10. The main component of the polycrystalline oxide ceramics is MgO polycrystalline material.
Alternatively, the method for producing a large-sized superconducting intermediate according to Item 9. 11. The method for producing a large-sized superconducting intermediate according to claim 8, wherein the oxide superconducting raw material molded body having the lowest Tp contains Yb element. 12. The oxide superconducting raw material molded body containing 1 to 30% by mass of an Ag element is laminated in at least one layer on the laminated body, according to any one of claims 8 to 11. Manufacturing method of large-scale superconducting intermediate. 13. The raw material molding laminate comprises 0.001 to 2.0 mass% of Rh element, 0.05 to 5.0 mass% of Pt element, or 0.05 to 1
A method for producing a large-sized superconducting intermediate according to any one of claims 8 to 12, characterized in that at least one layer of a raw material molding containing at least one element of 0.0 mass% Ce element is laminated. . 14. Oxygen enrichment after excising an oxide superconducting layer containing a seed crystal and a repulsion phase from the oxide superconducting intermediate obtained by the manufacturing method according to claim 8. A method for producing a large-sized superconductor characterized by performing a treatment.