JPH02248301A - Production of oxide superconductor - Google Patents

Abstract

PURPOSE:To accurately control the oxygen concn. in an oxide superconductor by allowing a current to flow through the laminate of an oxide superconductor and a solid electrolyte having oxygen ionic conductivity in the laminating direction in the temp. range where the latter exhibits oxygen ionic conductivity. CONSTITUTION:A superconductor thin film 2 of Y1Ba2Cu3O7-delta is formed at the center of the surface of a solid electrolyte substrate 1 consisting of a Y2O3-ZrO2 single crystal by sputtering, for example, heat-treated in an O2 atmosphere and crystallized. In this case, a porous plate-shaped platinum electrode 3 is previously formed on the surface opposite to the film 2-forming surface of the substrate 1. An MgO thin film 4a is then formed in contact with the film 2 on the substrate 1 to mask the film 2 by excimer laser sputtering as an insulating barrier layer 4. An equally spaced four-terminal nonporous plate-shaped platinum electrode 5 is formed in the same way across the film 2 so that its one end is placed on the film 4a, and further an MgO thin film 4b, from which on end of the electrode 5 is exposed, is formed to completely cover the film 2. The negative and positive poles of a DC regulated power source 10 are then connected to the electrode 3 and 5 or 5 and 3, and the entire laminate is heated in the atmosphere to a temp. at which is substrate 1 exhibits oxygen ionic conductivity.

Description

[Detailed Description of the Invention] <Industrial Application Fields> The present invention is directed to one of the oxide superconductors! More specifically, the present invention relates to a manufacturing method of an oxide superconductor, in which the oxygen concentration of the oxide superconductor can be accurately controlled and fixed as it is.

(Prior art) Oxide superconductors have a high critical temperature (Tc) that is not found in alloy-based superconducting materials currently in practical use, so they are used in conducting wires, magnetic shielding materials, and Josephson junctions. It is expected to be applied in many fields such as devices.

On the other hand, the physical properties of oxide superconductors largely depend on their oxygen concentration, and when considering the practical use of oxide superconductors,
It is said that it is necessary to precisely and stably control the oxygen concentration.

Conventional methods for controlling the oxygen concentration of oxide superconductors that have been known so far include a thermal oxidation method in the air or an oxygen atmosphere, and an oxidation method using oxygen plasma using sputtering or CVD. The front groove is mainly used to control the oxygen concentration in bulk and thick-film oxide superconductors, and the latter is mainly used to control the oxygen concentration in thin-film oxide superconductors.

(The problem that the invention is trying to solve) However,
When thermal oxidation is used, depending on the type of oxide superconductor, it may be difficult to apply the oxide superconductor to electronic devices because it must be heated to a high temperature. In addition, when using the oxidation method using oxygen plasma, the oxygen concentration of the oxide superconductor changes greatly depending on the plasma state, so for the purpose of application, we can reproducibly produce an oxide superconductor with a predetermined oxygen concentration. In order to obtain a good result, it is necessary to maintain the plasma state strictly at all times, which is often difficult in practice.

Furthermore, with these oxygen concentration control methods, it is difficult to quantitatively evaluate the amount of oxygen taken into the oxide superconductor.

As mentioned above, there is currently no simple means for accurately controlling the oxygen concentration in an oxide superconductor, and no means for stably maintaining the oxygen concentration.

The present invention was made in view of the current situation, and provides a method for producing an oxide superconductor that can stably produce an oxide superconductor with a predetermined oxygen concentration in which the oxygen concentration of the oxide superconductor can be accurately controlled. The first object of the present invention is to provide a method for producing an oxide superconductor that can produce an oxide superconductor with stable characteristics in which a controlled oxygen concentration can be fixed and maintained as it is.

(Structure and operation of the invention) The above objects are achieved by the invention as follows.

In other words, the method for producing an oxide superconductor includes a step of laminating an oxide superconductor and a solid electrolyte having oxygen ion conductivity, and a step of ionizing oxygen by passing oxygen through a position of the solid electrolyte facing the oxide superconductor. Alternatively, a step of stacking deionizing electrodes, a step of stacking an oxygen barrier electrode that does not allow oxygen to pass through at a position facing the solid electrolyte of the oxide superconductor, and a step of stacking the obtained laminate so that the solid electrolyte is This is a method for producing an oxide superconductor, comprising the step of controlling the oxygen concentration of the oxide superconductor by passing a current between the electrodes while maintaining the temperature within a temperature range that exhibits ionic conduction.

In the present invention described above, when a solid electrolyte having oxygen ion conductivity and an oxide superconductor are laminated, and a current is passed in the stacking direction in a temperature range in which the solid electrolyte exhibits M ion conductivity, the oxide superconductor The inventors have discovered that the oxygen concentration can be adjusted, and that the oxygen concentration can be accurately controlled by the amount of electricity (coulomb 1).

In the present invention described above, when a solid electrolyte and an oxide superconductor are laminated and the oxide superconductor is covered with an oxygen barrier layer so that no exposed portion is exposed, the lamination reaches a temperature at which the solid electrolyte no longer exhibits oxygen ion conduction. When the body is cooled, the solid electrolyte becomes an oxygen barrier layer, so the oxygen concentration in the oxide superconductor remains fixed at a υ-controlled value. Therefore, Y-Ba is affected by the atmosphere and the oxygen S degree easily changes.
Even oxide superconductors such as -Cu-O system have the effect of being able to accurately control the oxygen concentration and maintain it at a stable value over a long period of time. Further, if necessary, the oxygen concentration can be periodically controlled to recover the characteristics.

In addition, as is clear from the examples described later, in the present invention, it is easy to measure the resistivity of the oxide superconductor, and instead of measuring the amount of electricity described above, the resistivity is measured and the oxygen concentration is controlled. By doing so, the accuracy of controlling the oxygen concentration can be further improved.

In the present invention, the order of carrying out the step of laminating the oxide superconductor and the solid electrolyte and the step of laminating each electrode is arbitrary and not particularly limited.

The present invention will be explained in detail below.

If the oxide superconductor to which the present invention is applied is an oxide superconductor that exhibits mixed electronic and ionic conductivity, the type, material, and ratio of electronic conductivity and ionic conductivity to the total conductivity are particularly important. There are no restrictions. Such oxide superconductors include, for example, La-8r-CLI-0-based superconductors having the -format;
Ln 3a 2 CLI 3 0y −δ (L
n=Y, La.

Nd, 5IIIl, Eu, Gd,
Dy, Ho, Er.

■ m, Yb, lu, δ-〇~1)
-Cu-0 based superconductor, -Format: B I 2Srz
Can-+ CLInOV (V≦2n+4; n=1.
2.3) Bi-3r-CaCu-0 superconductor, -format: Tu2Ba2Can-ICLln
T expressed as OV (V≦2n+4; n=1°2.3)
Examples include U-Ba-Ca-Cu-O superconductors. By the way, as mentioned above, the present invention enables accurate oxygen concentration control at low temperatures and also has a structure that is stable over time, and is preferably applied to various applications that require such a structure, especially electronic device applications. It is possible.

Further, the type and material of the solid electrolyte having oxygen ion conductivity used in the present invention are not particularly limited as long as it has oxygen ion conductivity. Such solid electrolytes include Y203 Zr 02 (YSZ), CaOZr
02 (C8Z), B! 203.

Bi20a-Y20a, B! 203
-Nb20s.

Bi203-WOa and the like are known, but the present invention uses a material that has high oxygen ion conductivity, low electronic conductivity, has a dense structure, and has high oxygen barrier properties outside of conditions that exhibit oxygen ion conduction. is preferred.

From this point, Y203-Zr 02 (YSZ).

An oxide solid solution solid electrolyte having a fluorite (Ca F2 ) type crystal structure, such as CaOZr 02 (C8Z), is desirable.

Note that there are no particular limitations on the thickness, size, and shape of the oxide superconductor and the solid electrolyte having oxygen ion conductivity. Furthermore, the oxide superconductor may be a single oxide, formed as a device, or even formed as a part of an electronic device or the like.

Next, the procedure of the manufacturing method of the present invention will be explained. First, the above-described oxide superconductor and a solid electrolyte having oxygen ion conductivity are laminated. This stacking method is not particularly limited as long as the oxide superconductor and the solid electrolyte are connected to the extent that they can exchange oxygen ions. However, these conditions must be selected so that when a solid electrolyte having oxygen ion conductivity is actually stacked on the target oxide superconductor, the stack is mechanically stable. For example, as a preferable example, if a thin film of a solid electrolyte having oxygen ion conductivity is laminated on one side of a mechanically stable plate-shaped oxide superconductor by a physical vapor deposition method such as sputtering,
When a thin film of an oxide superconductor is laminated on one side of a mechanically stable plate-shaped solid electrolyte with oxygen ion conductivity by physical vapor deposition such as sputtering, or when a mechanically stable plate-shaped oxide An example of this is when a physical superconductor and a mechanically stable plate-shaped solid electrolyte having oxygen ion conductivity are bonded by mechanical pressure in a timely manner.

Once a laminated body of an oxide superconductor and a solid electrolyte having oxygen ion conductivity that satisfies the above-mentioned predetermined conditions is formed, electrodes are placed on the surfaces of the laminated oxide superconductor and solid electrolyte, respectively. do. On the oxide superconductor side, a non-porous electrode that does not pass through Fa element is formed on a part of its surface so as not to contact the solid electrolyte. This electrode is made of a conductive material that has only low electronic conductivity and high electrical conductivity, and there is no particular limit to its type as long as it is chemically stable, but platinum or gold are preferred examples. It will be done. In addition, on the solid electrolyte side, there are porous holes on a part of the surface of the solid electrolyte that allow oxygen to pass through for ionization or deionization so that the solid electrolyte can exchange oxygen with the atmosphere without contacting the oxide superconductor. form a quality electrode. This electrode is
There are no particular restrictions on the type of conductive material as long as it is a highly conductive material that exhibits electronic conductivity, is chemically stable, and has a porous structure, but platinum is a preferred example.

Although there are no particular restrictions on the thickness and area of each electrode, it is desirable that the area of the electrode be at least a fraction of the contact area between the oxide superconductor and the solid electrolyte.

After electrodes are formed on the laminate, a DC power source is connected between the formed nonporous electrode and the porous electrode, and the laminate is heated from room temperature in the air or an atmosphere containing oxygen and kept at a constant temperature. This temperature must be within the temperature range in which the oxide superconductor and solid electrolyte used in the stack allow oxygen to be injected or discharged in the oxide superconductor, and in which oxygen ion conduction can occur in the solid electrolyte. There are no particular restrictions. This temperature varies depending on the solid electrolyte used, the characteristics of the target oxide superconductor, etc., but is usually in the temperature range of about 300 to 900°C.

To increase the acidity of the oxide superconductor, connect the cathode of a DC power supply to the electrode on the solid electrolyte side and the anode to the electrode on the superconductor side, and maintain the stack at a constant temperature as described above. In this state, an appropriate amount of current is applied. Then, oxygen molecules and electrons react with each other at the solid electrolyte porous electrode, generating oxygen ions. These oxygen ions are ionically conducted through the solid electrolyte and injected into the oxide superconductor. The implanted oxygen ions are taken into oxygen vacancies in the oxide superconductor and combine with surrounding ions.

Inside an oxide superconductor, electrons are emitted to maintain charge neutrality. The emitted electrons pass through the non-porous electrode of the oxide superconductor and return to the anode of the power source.

Note that since the nonporous electrode uses a conductive material that exhibits only electron conductivity, oxygen ions are blocked and only electrons pass through.

Conversely, to reduce the oxygen concentration in the oxide superconductor, the polarity of the DC power source is reversed and an appropriate amount of current is passed while maintaining the same temperature as above. Then, inside the oxide superconductor of the stack, a reverse reaction to the above-mentioned reaction proceeds, and oxygen ions are discharged from the oxide superconductor to the solid electrolyte. The discharged oxygen ions pass through the solid electrolyte, absorb electrons at the porous electrode of the solid electrolyte, that is, are deionized, and are released as oxygen molecules.

There is no particular limit to the magnitude of the current applied to the laminate, but it goes without saying that it must be within the range of the size of the scar so that the laminate is not destroyed.

The oxygen concentration in the oxide superconductor can be adjusted by flowing a current in the stacked direction of the stack as described above and adjusting the direction, magnitude, and duration of the current. Then, when a predetermined oxygen concentration is obtained, the current is stopped and the stack is cooled to a temperature at which oxygen ion conduction in the solid electrolyte stops.
The degree can be fixed.

However, after controlling the oxygen concentration in the oxide superconductor as described above, if the oxygen partial pressure at the interface between the oxide superconductor and the solid electrolyte differs from the oxygen partial pressure in the atmosphere,
Even after the current is stopped, a small amount of oxygen ions move between the oxide superconductor and the solid electrolyte, and electric polarization occurs in the solid electrolyte depending on the difference in oxygen partial pressure, causing slight fluctuations in the oxygen concentration. It is conceivable that this may occur. To deal with this, while applying a voltage of sufficient magnitude in the stacking direction of the stack to maintain the oxygen concentration obtained after the energization ends, stack the stack until the temperature at which the 811 element ion conduction of the solid electrolyte stops. By cooling the body, the controlled oxygen concentration can be kept unchanged. Therefore, this control method is preferably applied when it is necessary to more strictly control the oxygen concentration in the oxide superconductor.

By the way, depending on the type of oxide superconductor, there are some that exchange oxygen with the atmosphere in their exposed parts, and the method described above alone cannot control or fix the @ element concentration. It may be difficult to do so. In the case of such an oxide superconductor, after forming electrodes on the laminate as described above, the surface of the oxide superconductor exposed to the atmosphere is blocked to prevent oxygen from passing through. After coating with a material that has a high oxygen barrier property and is electrically insulating, the oxygen concentration may be adjusted as described above. This coating material is not particularly limited as long as it has the above-mentioned oxygen barrier properties, and for example, known sealants for electronic devices can be used, but from the viewpoint of heat resistance etc., AlI3
3. MgO.

Ship A 203 Ceramic dielectrics such as MQO, SiO2, and Si3Ng are preferred.

In this way, if the exposed parts of the oxide superconductor are coated with an oxygen barrier layer as necessary during the formation stage of the laminate, the oxide superconductor and the solid electrolyte on which it is stacked can also normally absorb oxygen. Since it has barrier properties, the entire surface is covered with an oxygen barrier layer except when adjusting the oxygen concentration.
Even in oxide superconductors where the oxygen concentration is unstable, it becomes possible to control and fix the oxygen concentration.

By following the above procedure, the desired oxide superconductor can be manufactured and oxygen ar11 can be controlled.

Examples of the present invention are shown below.

(Example) As shown in FIG. 1, in the center of a solid electrolyte substrate (hereinafter referred to as "YSZ substrate") 1 made of a flat YSZ single crystal with a size of 20M x 20JIl and a thickness of IM, Y
While heating the SZ substrate 1 to 200°C, a 1 μm thick Y-
Ba-Cu-0 thin film (specifically Y+ Ba 2 C
After forming a Y-Ba-Cu-O thin film 2 to a size of 10 #ll x 10M, heat treatment was performed at 900° C. for 1 hour in an oxygen atmosphere to crystallize the Y-Ba-Cu-0 thin film 2. However, this heat treatment is performed using Y-Ba-CI-0111!
i! This was carried out to crystallize 2, and was not carried out for the purpose of controlling its oxygen concentration. YSZ is known as a solid electrolyte having oxygen ion conductivity.

Further, Y-Ba-Cu-0 is known as an oxide superconductor having oxygen vacancies.

By the way, as shown in the figure, a porous flat platinum electrode 3 was previously formed on the surface of the YSZ substrate 1 opposite to the surface on which the oxide superconducting thin film 1112 was formed, as follows. That is, the platinum paste was applied to the surface of the YSZ substrate 1 and then heated to about 1000° C. in the atmosphere. As shown in the figure, the porous flat platinum electrode 3 has a diameter of 15jw+X1 which is larger than the oxide superconducting thin ll12.
It was made into a plate shape with a size of 5 m+, and was formed so as to face it as shown in the figure.

Next, as an insulating oxygen barrier layer 4, a 1 μm thick Mo
011114a was formed on the film-coated YSZ substrate 1 by using an excimer laser sputtering device while heating the film to 400° C. and masking Y-Ba-Cu-0-11A2. Similarly, using an excimer laser sputtering device, as shown in FIG.

A four-terminal nonporous flat platinum electrode 5 in which four electrodes each having a length of 15 as and a thickness of 1 μm are arranged at predetermined intervals is Y-Ba −
It crosses over Cu-OiHIIJ2 and one end of it (M(1
The above-mentioned M(l OII'J
The attached YSZ substrate 1 was formed while being heated to 300°C. Further, the electrode can YSZ substrate 1 was placed at a 40-degree angle so that one end of the formed non-porous flat platinum electrode 5 was exposed and no surface of the y-Ba-Cu-0'fiJ film 2 was exposed.
While heating to 0° C., a 1 μm thick MaO film 4b was formed as an electrically insulating oxygen barrier layer 4 using the same excimer laser sputtering device. The purpose of this oxygen barrier layer 4 is to prevent the S degree of oxygen from changing when a part of the Y-3a-CuO book 112 is exposed to the atmosphere.

Next, the cathode of the DC stabilized power supply 10 was connected to the porous flat platinum electrode 3, and the anode was connected to the non-porous flat platinum electrode 5.
While heating the entire layered body in the atmosphere at 500° C., the temperature at which the YSZ substrate 1 exhibits oxygen ion conductivity, a current of 1 mA was passed intermittently for 10 seconds at a time, and then the YSZ substrate 1 was heated to 500° C.
The resistivity of 1 g12 of Cu-0 thin film was measured by the DC four-terminal method. Then, as shown by the solid line in Figure 3, the resistivity decreased as the amount of coulombs (the amount of energized electricity) increased. Next, when the polarity of the DC stabilized power supply 10 was reversed and a current of 1 mA was passed intermittently in the opposite direction for 10 seconds in the same manner as above, the resistivity was reversed as shown by the broken line in Figure 3. It started to increase and then returned to its original value. These series of YBa −
The change in Cu-ONN22 resistivity was reversible. In addition, from the measurement of the amount of energized electricity (coulomb amount), there is a good correlation between the amount of energized electricity and the amount of injected oxygen ions, and the oxygen concentration can be controlled accurately by the energized electricity m and resistivity. It turns out that it can be done.

It is considered that the excellent oxygen barrier properties of the Mu 01 film used as the oxygen barrier layer contribute to this good correspondence with almost no hysteresis.

According to analysis, the Mg0Il used in this example is a polycrystalline film in which the (111) plane is oriented in a direction perpendicular to the film surface, and therefore, from the above point of view, a polycrystalline or single-crystalline MgO film with such an orientation is preferable.

Next, when the DC stabilized power supply 10 is turned off and the laminate is returned to chamber m, the resistivity of Y-Ba-Cl-0 thin 1!2 is 5.
It was fixed at the last value obtained at 00°C.

Y-Ba-Cu-0 is an oxygen-deficient oxide superconductor, and it is known that the resistivity decreases as the oxygen concentration increases. Therefore, the change in resistivity of Y-Ba-Cu-081I2 at 500°C shown above is from the YSZ substrate 1 to the Y-[3a-Cu-0 thin 112,
II! Ions are implanted or ejected, and Y-Ba −
This corresponds to the fact that the oxygen concentration of the CLI-0 thin film 2 is controlled. Moreover, at room temperature, Y-Ba-Cu-
The reason why the resistivity of the 0 thin film 2 became constant corresponds to the fact that the oxygen concentration was fixed.

After the above measurements were completed, the Y-
Oxygen ions were implanted into the Ba-Cu-01 film 2 from the YSZ substrate 1, and changes in the characteristics of the Y-Ba-Cu-0 thin film 2 were investigated. The steps are below.

The cathode of the DC stabilized power supply 10 was connected to the porous flat platinum electrode 3, the anode was connected to the non-porous flat platinum electrode 5, and the
At 0° C., a current of 1 mA was applied for 20 seconds with an amount of electricity of 2×10 −2 coulombs.

After energization, the laminate is quickly cooled to room temperature and Y-B
The low-temperature resistivity of Y-Ba-Cu-0iJ-2 was measured using the DC four-probe method described above after cooling the boar with a fixed oxygen concentration of a-CLI-0f11112 using liquid helium. The C-axis length of the grating was measured. Subsequently, the same operation as above was repeated twice. In other words, the total amount of electricity of 6X1G-2 coulombs is 2
Y-Ba-Cu divided into 3 times of X10-2 coulombs
-0thin 112, each time the above-mentioned Y-Ba-C
The low-temperature resistivity and C-axis length of u-0 thin film 2 were measured.

Also, after all the above operations were completed, I left it indoors for more than a week, but the Y-Ba-Cu-0 book 11! ! ! No change over time was observed in the resistivity of No. 2.

Figure 4 shows Y-Ba at each amount of electricity measured above.
The relationship between the resistivity and temperature at low temperatures of -Cu -0 thin WA2 is shown. In the figure, each of the curves A, B, and C has an integrated amount of electricity of 2X10-2 coulombs (A).

4x10-2 coulombs (B), 6x10-2 coulombs (
The low-temperature resistivity of Y-Ba-Cu-0 thin M2 in each case of C) is shown. In the case of B and C, a superconducting state was not obtained in the measured temperature range of 6 to 273, but in the case of B and C, a superconducting state was obtained at IOK and 57, respectively. In other words, as the amount of oxygen injection increases, Y-Ba-Cu-0 thin llI
The superconducting properties of No. 2 are clearly improved.

Fig. 5 shows the energized electric current and YBa-Cu
- The relationship between the Q-value and the C-axis length of the membrane 2 is shown. It can be seen that the length of the C-axis becomes shorter as the energized electric current increases.

By the way, in Y+ Ba 2 C030y -6 superconductor, when the oxygen stoichiometric number (7-δ) is within the range of 6 to 7, the larger the value of (7-δ), the more the resistance becomes zero. It is known that the critical temperature TO is high and the length of the C axis is short (for example, Japan Journal
of Applied Physics, 26. (
7).

(1987), +11156, 5olids
tateCommunications, 66, (
9), (1988), p953).

The results shown in FIGS. 4 and 5 shown above are consistent with these known findings. Therefore, it is clear that according to the present invention, oxygen ions are implanted into the Y-Ba-Cu-0 thin film 2 in accordance with the amount of electricity applied, and the oxygen concentration of the Y-Ba-Cu-0 thin film 2 can be accurately controlled. It can be understood that this greatly contributes to the stable production of high-quality oxide superconductors.

(Effects of the Invention) As described above, the present invention uses a solid electrolyte having oxygen ion conductivity to accurately control the oxygen concentration in an oxide superconductor at a relatively low temperature, and also allows it to be fixed as it is. Accurate control of the M element concentration of 1 and II and its long-term stability have a great effect on the stable production of oxide superconductors and various devices using oxide superconductors, which are said to be essential for practical use. As described above, the present invention is industrially very useful and makes a significant contribution to the practical application of oxide superconductors.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the example, Figure 2 is a plan view of the laminated portion of the example, and Figure 3 is a graph showing the relationship between the amount of energized electricity and resistivity of the example, where the horizontal axis is the amount of energized electricity. (X10-2 R10), the l axis is resistivity (lΩ・C#I), and FIG. 4 is a graph showing the relationship between temperature and resistivity in the example, and the horizontal axis is temperature (K ), the vertical axis is the resistivity (lΩ・α), and FIG. ), the vertical axis is the length (in) of the C axis of the unit cell. 1: Solid electrolyte (YSZ) substrate 2 Dioxide superconductor (Y-Ba-Cu-0) Thin film 3: Porous flat platinum electrode 4: Oxygen barrier layer 5: Non-porous flat platinum electrode 10: DC stable Power Supply Figure 1 Patent Applicant Teijin Ltd. Nozomi Ishi Kame No. 22 Resistivity (mΩ cm) Resistivity (mΩ cm) Resistivity (mΩ cm)

Claims (1)

[Claims] 1. In a method for producing an oxide superconductor, a step of stacking an oxide superconductor and a solid electrolyte having oxygen ion conductivity, and stacking the solid electrolyte opposite to the oxide superconductor. A step of laminating an electrode that allows oxygen to pass through and ionizes or deionizes the electrode, and a step of laminating an electrode with an oxygen barrier property that does not allow oxygen to pass through the electrode at a position facing the solid electrolyte of the oxide superconductor.
An oxidation process characterized by a step of controlling the oxygen concentration of the oxide superconductor by passing a current between the electrodes while maintaining the obtained laminate in a temperature range in which the solid electrolyte exhibits oxygen ion conduction. Method for producing physical superconductors. 2. The method for producing an oxide superconductor according to claim 1, further comprising the step of coating the oxide superconductor, which is laminated with a solid electrolyte and on which the electrode is laminated, with an oxygen barrier. The oxide superconductor according to claim 1 or 2, wherein in the step of controlling the oxygen concentration, the resistivity of the oxide superconductor is measured and the current is stopped when the resistivity reaches a predetermined value. How the body is manufactured. After controlling the oxygen concentration, the stack is cooled to a temperature at which the solid electrolyte no longer exhibits oxygen ion conductivity while applying a voltage necessary to maintain the oxygen concentration between the two electrodes, and then the voltage application is stopped. A method for producing an oxide superconductor according to any one of claims 1 to 3. 5. The method for producing an oxide superconductor according to any one of claims 1 to 4, wherein the oxide superconductor is a Y-Ba-Cu-O based oxide superconductor. 6. The method for producing an oxide superconductor according to claim 5, wherein the oxide superconductor is laminated on a solid electrolyte substrate by a vapor deposition method such as a sputtering method.