JPH1111943A - Oxide superconductor and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an oxide superconductor having a high critical current density even in a high magnetic field by incorporating a specified amt. of a specified element (compd.) into an RE-Ba-Cu-O superconductor. SOLUTION: The oxide superconductor contains 0.05-1 wt. % one or more among Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Sr, Zr, Nb, Mo, Tc, In, Sn, Sb, Tc, Cs, La, Ce, Pt, Nd, Hf, Ta, W and Bi in an oxide superconductor contg. an RE2 BaCuO5 phase (RE is Y, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu) finely dispersed in an REBa2 Cu3 O7-x phase. It may contain 0.05-5 wt.% one or more among Pt, Pd, Ru, Rh, Ir, Os and Re (compds.) or may further contain 1-30 wt.% Ag. The objective oxide superconductor is obtd. by adding such elements (compds.) at the time of producing the RE-Ba-Cu oxide superconductor by a melting method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxide superconductor having a uniform and high critical current density used for current leads, magnetic bearings, magnetic shields, bulk magnets, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art An oxide superconductor having a uniform and high critical current density used for a current lead, a magnetic bearing, a magnetic shield, a bulk magnet and the like is manufactured by RE.
Compound (RE is Y, Sm, Eu, Gd, Tb, Dy, H
a raw material mixture containing at least one rare earth element selected from the group consisting of o, Er, Tm, Yb, and Lu), a Ba compound, and a Cu compound; RE-B
A method of producing an a-Cu-O-based oxide superconductor is known (for example, see Japanese Patent Publication No. 7-51463).

The method described in Japanese Patent Publication No. 7-51463 discloses a method in which a raw material mixture in which RE, Ba, and Cu compounds are mixed at a predetermined molar ratio is melted once, rapidly solidified, and then solidified. The superconducting phase is grown by finely pulverizing the mixture, heating the mixture again to a high temperature region which partially exhibits a liquid phase, and then slowly cooling the mixture. Further, by performing an annealing treatment in an oxygen atmosphere, an oxide superconductor having a relatively high critical current density is obtained.

[0004] By this method, RE-Ba-Cu-O
When a system-based superconductor is produced, a structure in which the RE ₂ BaCuO ₅ phase is finely dispersed in the REBa ₂ Cu ₃ O _7-X phase is obtained,
The RE ₂ BaCuO ₅ phase functions as a pinning center for pinning magnetic flux, and has an effect of increasing the critical current density.

[0005]

However, the RE ₂
Since the pinning force of the BaCuO ₅ phase is weakened by the presence of the magnetic field, sufficient characteristics cannot be obtained in a high magnetic field only by the pinning point of the RE ₂ BaCuO ₅ phase.

The present invention has been made to solve the above problems, and has as its object to provide an oxide superconductor having higher critical current density characteristics even in a high magnetic field, and a method for manufacturing the same.

[0007]

Means for Solving the Problems As means for solving the above problems, the invention of claim 1 relates to a REBa ₂ Cu ₃ O _{7 -X} phase (RE is Y, Sm, Eu, Gd, Tb, Dy, Ho, E
In the oxide superconductor in which the RE ₂ BaCuO ₅ phase is finely dispersed in one or more rare earth elements selected from r, Tm, Yb, and Lu), Mg, Al, Si, Ca,
Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Z
n, Sr, Zr, Nb, Mo, Tc, In, Sn, S
b, Tc, Cs, La, Ce, Pr, Nd, Hf, T
a, W, or Bi is one or more elements of 0.
An oxide superconductor characterized by containing from 05 wt% to 1 wt%.

According to a second aspect of the present invention, there is provided the oxide superconductor according to the first aspect, wherein Pt, Pd, Ru, Rh, Ir,
One or more of each metal or each compound of Os and Re is contained in an amount of 0.05 to 5 wt% (however, in the case of a compound, it is indicated by the amount of the metal contained in the compound). It is an oxide superconductor.

According to a third aspect of the present invention, there is provided the oxide superconductor according to the first or second aspect, wherein Ag is 1 to 30.
It is an oxide superconductor characterized by containing wt%.

[0010] The invention of claim 3 is a compound of the present invention, wherein RE is Y, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
A raw material mixture containing one or more rare earth elements selected from m, Yb, and Lu), a Ba compound, and a Cu compound is subjected to a treatment including a firing step at least in a temperature range higher than the melting point of the raw material mixture. In a method for producing an oxide superconductor for producing a RE—Ba—Cu—O-based oxide superconductor, Mg, Al, Si, Ca, Sc, Ti,
V, Cr, Mn, Fe, Co, Ni, Zn, Sr, Z
r, Nb, Mo, Tc, In, Sn, Sb, Tc, C
one or more of s, La, Ce, Pr, Nd, Hf, Ta, W, and Bi in an amount of 0.05 wt% to 1 wt.
wt. (however, in the case of a compound, it is indicated by the amount of the metal contained in the compound).

According to a fifth aspect of the present invention, in the method for producing an oxide superconductor according to the fourth aspect, the raw material mixture further includes a metal of Pt, Pd, Ru, Rh, Ir, Os, or Re. One to two or more of each compound is 0.05 to 5 w
The present invention provides a method for producing an oxide superconductor, characterized by adding t% (however, in the case of a compound, the amount is indicated by the amount of the metal contained in the compound).

According to a sixth aspect of the present invention, in the method for producing an oxide superconductor according to the fourth or fifth aspect, Ag is further added to the raw material mixture in an amount of 1 to 30 wt%. This is a method for manufacturing a superconductor.

RE compounds (RE is Y, Sm, Eu, G
d, Tb, Dy, Ho, Er, Tm, Yb, Lu, at least one or more rare earth elements), a Ba compound and a Cu compound, at least higher than the melting point of the raw material mixture. When subjected to a treatment comprising a calcination step in the temperature range to produce the RE over Ba over Cu over O-based oxide superconductor, in REBa ₂ Cu ₃ O _7-X phase 0.1 to 30
The RE ₂ BaCuO ₅ phase of about μm is finely dispersed, and the critical current density can be increased.

Further, Mg, Al, S is added to the raw material mixture.
i, Ca, Sc, Ti, V, Cr, Mn, Fe, Co,
Ni, Zn, Sr, Zr, Nb, Mo, Tc, In, S
n, Sb, Te, Cs, La, Ce, Pr, Nd, H
When one or more elements of any one of f, Ta, W, and Bi are added in an amount of 0.05 wt% to 1 wt%, these elements become R in the REBa ₂ Cu ₃ O _{7 -X} phase exhibiting superconductivity.
E, Ba, or Cu sites are partially substituted, and fine and partially weak portions of superconductivity are formed. Such a portion changes from a superconducting state to a normal conducting state under a high magnetic field, and functions as a new pinning center. Therefore, such a new pinning center is generated even under a high magnetic field, so that a high critical current density can be obtained even under a high magnetic field.

If the amount of addition is less than 0.05 wt%, the effect is small, and if it is more than 1 wt%, the portion having low superconductivity is too large, and the overall characteristics are also deteriorated.

Pt may be mixed in from a platinum crucible or the like when performing a process for preparing a raw material mixture for forming a superconductor.
It has been confirmed that even when contained within the range, high characteristics are similarly exhibited. Also, Pt, Pd, Ru, Rh, Ir,
Os, Re metal or compound powder 0.05-5w
It has been confirmed that even when added in the range of t%, high characteristics are similarly exhibited.

Further, a metal or compound powder of Ag is added to 1
Addition of ３０30 wt% improves mechanical strength and water resistance.

[0018]

Embodiment

(Example 1) After weighing each raw material powder of Y ₂ O ₃ , BaCO ₃ , and CuO so that Y: Ba: Cu = 18: 24: 34, only BaCO ₃ and CuO were measured in air at 880 ° C.
For 30 hours to obtain a calcined powder of BaCuO ₂ and CuO (molar ratio: BaCuO ₂ : CuO = 24: 10). Next, the calcined powder was ground using a pot mill to have an average particle size of about 2 μm, and then Y ₂ O ₃ having an average particle diameter of about 1 μm and an average particle diameter of about 0.1 μm were weighed in advance.
0.5 wt% of 02 μm Pt powder was added. Next, the required number of the mixture thus prepared is prepared, and each of them is further added with Mg, Al, Si, Ca,
Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Z
n, Sr, Zr, Nb, Mo, Tc, In, Sn, S
b, Te, Cs, La, Ce, Pr, Nd, Hf, T
a, W, and Bi were added and mixed at 0.4 wt%, respectively. Next, these mixed powders were each heated in the air from room temperature to 930 ° C. in 10 hours,
After holding for 30 hours, the temperature was lowered to room temperature over 10 hours, and calcination was performed. Each of the calcined mixed powders was pulverized with a raikai machine to have an average particle size of about 5 μm. Next, each of these was set to an outer diameter of 50 mm and a thickness of 20 mm.
Was pressed into a disk shape to produce a molded body.

Each of these compacts was placed on an alumina substrate and heated in the air at 1130 ° C. for 50 hours, and then held for 30 minutes to be in a semi-molten state. The temperature was rapidly lowered (approximately 10 ° C./min) until the upper temperature on molding reached approximately 1000 ° C. so that a temperature gradient of 5 ° C./cm was applied vertically.
The seed crystal of the dBaCuO-based melt is brought into contact with the upper part of the compact so that the growth direction is parallel to the c-axis, and the temperature is maintained at about 995 ° C. for about 60 hours at which crystallization starts, and then 1 ° C.
/ Hr was gradually cooled to 900 ° C., and then cooled to room temperature at 10 ° C./h to perform crystallization.
FIG. 1 is a diagram showing a firing temperature pattern of Example 1.

Each of the crystallized compacts is placed in a furnace capable of gas replacement. That is, first, the inside of the furnace is evacuated to 0.1 Torr by a rotary pump, and then an oxygen gas is poured into the furnace to obtain an atmosphere at an atmospheric pressure where the oxygen partial pressure is 95% or more. Thereafter, while flowing oxygen gas into the furnace at a flow rate of 0.5 L / min, the temperature was raised from room temperature to 450 ° C. for 10 hours, gradually cooled from 450 ° C. to 250 ° C. over 200 hours, and then cooled from 250 ° C. to room temperature. Let cool in 10 hours.

[0021] When a cross section by cutting the respective material obtained was observed with an optical _{microscope, YBa 2 Cu 3 O 7-} X phase 0.1~30μm of Y ₂ BaCuO ₅ phase in is not finely dispersed Was. In addition, the entire material was oriented along the c-axis reflecting the seed crystal, and a substantially single-crystal material was obtained.

Approximately 2 × 2 ×
A single crystal of about 1.5 mm was cut out, and a magnetic field was applied in parallel to the c-axis by a sample vibration magnetometer to measure the magnetic susceptibility at a temperature of 77 [K]. From the measurement results of the magnetic susceptibility, a critical current density was obtained by applying a Bean model.

FIG. 2 shows the magnetic field dependence of the critical current density of the sample to which Sr is added and the sample to which Sr is not added. In the sample to which Sr was added, the critical current density was low at a low magnetic field near 0 [T], but the attenuation was small with an increase in the magnetic field, and the value was higher at 0.2 [T] or more than that without the addition.

FIG. 3 shows the critical current densities of the sample to which an additional element was added at an external magnetic field of 1 [T]. It can be seen that a high critical current density is exhibited even under a high magnetic field.

Current lead, magnetic bearing, magnetic shield,
In the case of application of a bulk magnet or the like, the external magnetic field substantially applied to the sample is 0.5 T or more. Therefore, the characteristic value of the applied technology can be significantly improved by increasing the critical current density under a high magnetic field.

(Example 2) Ho ₂ O ₃ , BaCO ₃ , C
Each raw material powder of uO was prepared using Ho: Ba: Cu = 18: 24: 3.
After weighing so as to be 4, only BaCO ₃ and CuO are calcined at 880 ° C. for 30 hours in the air, and BaCuO ₂ and C
A calcined powder of uO was obtained (in molar ratio, BaCuO ₂ : CuO =
24:10). Next, the calcined powder was pulverized using a pot mill to make the average particle size about 2 μm.
Pre-weighed Ho ₂ O with average particle size of about 1 μm
₃ and 0.5wt% of Pt powder with average particle size of about 0.02μm
Was added. Next, a required number of the mixtures thus prepared are prepared, and as further additives, 0.1 wt% of Al, 0.3 wt% of Ca, and 0.1 w
0.2% by weight of t% and Mg, 0.2% by weight of Zn and 0.3% by weight of Nb, 0.1% by weight of In and 0.5% by weight of Sn, 0.3% by weight of Ti and 0.4% by weight of La
t%, Ce 0.3 wt%, Pr0.3 wt%, N
0.1 wt% of d and 0.5 wt% of Bi were added to each other and mixed. Next, each of these mixed powders was heated in the air from room temperature to 930 ° C. for 10 hours, held for 30 hours, and then fired by cooling to room temperature over 10 hours. Each of the calcined mixed powders is pulverized by a raikai machine to have an average particle size of about 5 μm.
m. Next, each of them was made to have an outer diameter of 50 mm and a thickness of 2 mm.
A compact was produced by press molding into a 0 mm disk shape.

Each of the compacts thus prepared was placed on an alumina substrate and brought into a semi-molten state at 1130 ° C. in the air, and then vertically moved so that the upper portion of the compact was on the low temperature side.
Then, the temperature of the green body was rapidly lowered (approximately 10 ° C./min) until the upper temperature of the molded body reached approximately 1000 ° C. so that a temperature gradient of approximately 90 ° C./cm was applied. After contacting with the upper part of the compact so as to be parallel to the c-axis and keeping the temperature at around 995 ° C. where crystallization starts for about 60 hours, it is gradually cooled to 900 ° C. at a rate of 1 ° C./hr,
Then, the temperature was lowered to room temperature at 10 ° C./h to perform crystallization.

These crystallized compacts were placed in a furnace capable of gas replacement. That is, first, the inside of the furnace is evacuated to 0.1 Torr by a rotary pump, and then an oxygen gas is poured into the furnace to obtain an atmosphere at an atmospheric pressure where the oxygen partial pressure is 95% or more. Thereafter, the temperature was raised from room temperature to 450 ° C. for 10 hours while flowing oxygen gas into the furnace at a flow rate of 0.5 L / min.
Slowly cool from 450 ° C to 250 ° C over 200 hours,
The temperature is lowered from 50 ° C. to room temperature in 10 hours.

Each material obtained in this manner was cut, and its cross section was observed with an optical microscope. As a result, YBa ₂ Cu ₃
O _{7- X} phase in the 0.1 to 30 [mu] m Y ₂ BaCuO ₅ phase were dispersed finely. In addition, the entire material was oriented along the c-axis reflecting the seed crystal, and a substantially single-crystal material was obtained.

Approximately 2 × 2 ×
A single crystal of about 1.5 mm was cut out, and a magnetic field was applied parallel to the c-axis by a sample vibration magnetometer to measure the magnetic susceptibility at a temperature of 77 [K]. From the measurement results of the magnetic susceptibility, a critical current density was obtained by applying a Bean model.

FIG. 4 shows the critical current densities at an external magnetic field of 1 [T]. It showed a high critical current density even under a high magnetic field.

Example 3 Y ₂ O ₃ , BaCO ₃ , Cu
Each raw material powder of O is weighed and mixed so that Y: Ba: Cu = 18: 24: 34, and then put in a Pt crucible in the air.
It was melted at 400 ° C. for 30 minutes, poured into a copper plate and rapidly cooled. A required number of the solidified products thus obtained are prepared, and each of them is made of Mg, Al, Ca, Zn, Sr, Zr, Nb, S
0.1 wt% each of n, Sb, La, Ce, Bi
The mixture was added, and each was ground and mixed using a pot mill to make the average particle size about 2 μm. Next, these were each press-molded into a disk shape having an outer diameter of 50 mm and a thickness of 20 mm to produce a molded body.

Each of these compacts was placed on an alumina substrate and brought into a semi-molten state at 1130 ° C. in the air.
The temperature of the upper part of the molded body is rapidly lowered (about 10 ° C./min) until the upper part temperature of the molded body becomes 1000 ° C. so that a temperature gradient of 5 ° C./cm is applied vertically so that the upper part of the molded body is on the low temperature side. After the seed crystal of the NdBaCuO-based melt placed is brought into contact with the upper part of the compact so that the growth direction is parallel to the c-axis, and the temperature is maintained at about 995 ° C. for about 60 hours, at which crystallization starts,
Crystallization was performed by gradually cooling to 900 ° C. at a rate of 1 ° C./hr and then cooling to room temperature at 10 ° C./hr.

The crystallized compact was placed in a furnace capable of gas replacement. That is, first, the inside of the furnace is evacuated to 0.1 Torr by a rotary pump, and then an oxygen gas is poured into the furnace to make an atmosphere having an oxygen partial pressure of 95% at atmospheric pressure. Thereafter, while flowing oxygen gas into the furnace at a flow rate of 0.5 L / min, the temperature was raised from room temperature to 450 ° C. in 10 hours.
From 250 ° C to room temperature in 10 hours.

When the obtained material was cut and its cross section was observed with an optical microscope, it was found that 0.1% was contained in the YBa ₂ Cu ₃ O _7-X phase.
Y ₂ BaCuO ₅ phase ~30μm were dispersed finely.
In addition, the entire material was oriented along the c-axis reflecting the seed crystal, and a substantially single-crystal material was obtained.

Approximately 2 × 2 ×
A single crystal of about 1.5 mm was cut out, and a magnetic field was applied parallel to the c-axis by a sample vibration magnetometer to measure the magnetic susceptibility at a temperature of 77 [K]. From the measurement results of the magnetic susceptibility, a critical current density was obtained by applying a Bean model.

FIG. 5 shows the limiting current density at an external magnetic field of 1 [T]. It showed a high critical current density even under a high magnetic field.

Comparative Example 1 Y ₂ O ₃ , BaCO ₃ , Cu
After weighing each raw material powder of O so that Y: Ba: Cu = 18: 24: 34, only BaCO ₃ and CuO are fired at 880 ° C. for 30 hours in the air to obtain BaCuO ₂ and CuO.
(A molar ratio of BaCuO ₂ : CuO = 2) was obtained.
4:10). Next, the calcined powder was ground using a pot mill to have an average particle size of about 2 μm, and then Y ₂ O ₃ having an average particle diameter of about 1 μm and an average particle diameter of about 0.1 μm were weighed in advance. 0.5 wt% of 02 μm Pt powder is added and mixed. Next, the mixed powder was removed from the room temperature to 93
The temperature was raised to 0 ° C. in 10 hours, and maintained for 30 hours.
Calcination was performed by lowering the temperature to room temperature over time. The calcined mixed powder was pulverized with a raikai machine to have an average particle size of about 5 μm. Next, this is 50 mm in outer diameter and 20 mm in thickness.
Was pressed into a disk shape to produce a molded body.

After placing the compact on an alumina substrate and making it in a semi-molten state at 1130 ° C. in the air, a temperature gradient of 5 ° C./cm is applied up and down so that the upper portion of the compact is on the low temperature side. The temperature was rapidly lowered (approximately 10 ° C./min) until the upper temperature of the molded body reached approximately 1000 ° C.
The seed crystal of the aCuO-based melt is brought into contact with the upper part of the compact so that the growth direction is parallel to the c-axis, and crystallization starts 995.
After maintaining the temperature at about 60 ° C for about 60 hours, 1 ° C / hr
Slowly cool to 900 ° C at a speed of 10 ° C to room temperature
Crystallization was performed by lowering the temperature at / h.

The crystallized molded body was placed in a furnace capable of gas replacement. That is, first, the inside of the furnace is evacuated to 0.1 Torr by a rotary pump, and then an oxygen gas is poured into the furnace to obtain an atmosphere at an atmospheric pressure where the oxygen partial pressure is 95% or more.
Thereafter, while flowing oxygen gas at a flow rate of 0.5 L / min into the furnace, the temperature was raised from room temperature to 450 ° C. in 10 hours, and 45 ° C.
Cool slowly from 0 ° C to 250 ° C over 200 hours.
Let the temperature drop from ℃ to room temperature over 10 hours.

When the obtained material was cut and its cross section was observed with an optical microscope, it was found that the material contained 0.1% in the YBa ₂ Cu ₃ O _{7 -X} phase.
Y ₂ BaCuO ₅ phase ~30μm were dispersed finely. Also, the entire material is oriented along the c-axis reflecting the seed crystal,
A substantially single crystalline material was obtained.

Approximately 2 × 2 ×
A single crystal of about 1.5 mm was cut out, and a magnetic field was applied parallel to the c-axis by a sample vibration magnetometer to measure the magnetic susceptibility at a temperature of 77 [K]. From the measurement results of the magnetic susceptibility, the critical current density was determined by applying the Bean model.

FIG. 2 shows the magnetic field dependence of the critical current density together with the sample to which Sr was added. The attenuation is large with respect to the magnetic field,
Under high magnetic field, the critical current density was low.

In the above-described embodiment, Y and Ho are shown as examples of RE, respectively. However, as RE, Y, Sm, Eu, Gd, Tb, Dy, Ho, Er,
It has been confirmed that similar effects can be obtained by using one or more elements selected from Tm, Yb, and Lu.

[0045]

As described above in detail, the present invention provides an RE-Ba-Cu-O-based superconductor (RE is Y, Sm ,
Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, L
u, one or more rare earth elements selected from the group consisting of Mg, Al, Si, Ca, Sc, Ti, V,
Cr, Mn, Fe, Co, Ni, Zn, Sr, Zr, N
b, Mo, Tc, In, Sn, Sb, Te, Cs, L
a, Ce, Pr, Nd, Hf, Ta, W, Bi, at least one element of 0.05 wt% to 1 wt%
The addition of% makes it possible to produce an oxide superconductor exhibiting a critical current density even under a high magnetic field.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a temperature pattern of melt crystallization in Example 1.

FIG. 2 is a view showing the results of measuring the magnetic field dependence of the critical current density at a temperature of 77 [K] of the sample to which Sr was added in Example 1 and the material produced in Comparative Example 1.

FIG. 3 is a view showing a result of measuring a critical current density of the material manufactured in Example 1 at a temperature of 77 [K] and an external magnetic field of 1 [T].

FIG. 4 is a view showing a result of measuring a critical current density of a material manufactured in Example 2 at a temperature of 77 [K] and an external magnetic field of 1 [T].

FIG. 5 is a view showing a result of measuring a critical current density of a material manufactured in Example 3 at a temperature of 77 [K] and an external magnetic field of 1 [T].

Claims (6)

[Claims] 1. The REBa ₂ Cu ₃ O _7-X phase (RE is Y,
Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Y
b, one or more rare earth elements selected from Lu)
In an oxide superconductor in which an RE ₂ BaCuO ₅ phase is finely dispersed, Mg, Al, Si, Ca, Sc, Ti,
V, Cr, Mn, Fe, Co, Ni, Zn, Sr, Z
r, Nb, Mo, Tc, In, Sn, Sb, Tc, C
at least one element selected from the group consisting of s, La, Ce, Pr, Nd, Hf, Ta, W, and Bi is 0.05 wt% to 1 wt.
An oxide superconductor characterized in that the oxide superconductor is contained by wt%. 2. The oxide superconductor according to claim 1, wherein one or more of the metals Pt, Pd, Ru, Rh, Ir, Os, and Re, or a compound of these metals, is used in an amount of 0.0%.
An oxide superconductor comprising 5 to 5 wt% (in the case of a compound, the amount is indicated by the amount of the metal contained in the compound). 3. The oxide superconductor according to claim 1, comprising 1 to 30% by weight of Ag. 4. An RE compound (RE is Y, Sm, Eu, G
d, Tb, Dy, Ho, Er, Tm, Yb, Lu, at least one or more rare earth elements), a Ba compound and a Cu compound, at least higher than the melting point of the raw material mixture. A method for producing an RE-Ba-Cu-O-based oxide superconductor by performing a treatment including a firing step in a temperature region, comprising: Mg, Al, Si, Ca, Sc, Ti, V, Cr , M
n, Fe, Co, Ni, Zn, Sr, Zr, Nb, M
o, Tc, In, Sn, Sb, Tc, Cs, La, C
e, Pr, Nd, Hf, Ta, W, and Bi in an amount of 0.05 wt% to 1 wt% (in the case of a compound, the amount of the metal contained in the compound is 0.05 wt% to 1 wt%). A method for producing an oxide superconductor. 5. The method for producing an oxide superconductor according to claim 4, wherein the raw material mixture further comprises Pt, Pd, Ru, Rh,
A method for producing an oxide superconductor, comprising adding 0.05 to 5 wt% of one or more of each metal or each compound of Ir, Os, and Re. 6. The method for manufacturing an oxide superconductor according to claim 4, wherein Ag is further added to the raw material mixture in an amount of 1 to 30% by weight. .