JP3361016B2 - Superconducting member and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting member in which an oxide film is laminated on an oxide superconductor and a method for manufacturing the same.

[0002]

2. Description of the Related Art Since the discovery of oxide superconductors, the cooling cost has been low, so that they have been attempted to be applied in a wide range of fields such as microelectronics or high frequency equipment as well as electric power equipment. However, oxide superconductors have the drawbacks that they are easily dissolved in acid and that the superconducting properties deteriorate when water adheres. In particular, this defect is remarkable in the Y-based superconductor, and the critical current density Jc is halved only by exposing it to the atmosphere for several days. In order to solve this drawback, it has been considered to coat the surface of the superconductor with a material having excellent environmental resistance. In order to form a material having excellent environmental resistance on the surface of an oxide superconductor, it is generally necessary to raise the substrate temperature in vacuum. However, under the condition that the substrate temperature is high in vacuum, there is a problem that oxygen contained in the crystal of the superconductor easily escapes, and the critical temperature Tc and the critical current density Jc decrease. For example, when a crystallized film of MgO, YSZ, Al ₂ O ₃ or the like is laminated as a protective film on a Y-based superconductor, the critical temperature Tc was 87K before the lamination but 80K after the lamination. Critical current density Jc
Also decreased from 1 × 10 ⁶ A / cm ² to 1 × 10 ⁴ A / cm ² .

Therefore, for example, amorphous SiO ₂ , SiC, Si
_{Although a} protective film that can be formed at a low temperature such as ₃ N ₄ is also used, these films are easily peeled off by heat shock and do not exert their effects for a long period of time. Further, when a dielectric is laminated on the surface of a superconductor in order to manufacture an element applied to a high frequency device in the gigahertz band, similarly, there arises a problem that the critical temperature Tc and the critical current density Jc decrease.

[0004]

As described above, when the protective film or the dielectric film is formed on the surface of the oxide superconductor, there is a problem that the critical temperature Tc and the critical current density Jc are lowered.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a superconducting member having excellent environment resistance, a high critical temperature and a critical current density, and a manufacturing method thereof.

[0005]

[Means for Solving the Problems]

The present invention also provides an oxide superconductor and an oxide film formed on the oxide superconductor, the oxide film containing an element having a plurality of valences and deviating from the stoichiometric composition. Provided is a superconducting member.

[0007]

[0008]

The present invention also includes an oxide superconductor and an oxide which is formed on a part of the oxide superconductor and which has a plurality of valences and which deviates from the stoichiometric composition. A superconducting member comprising a film, wherein at least one of a critical temperature and a critical current density of the oxide superconductor in a region where the oxide film is formed is large.

The present invention also provides a substrate and a substrate formed on the substrate.
Formed oxide superconductor, and the oxide superconductor
A film of 500 angstroms or more formed on the upper part
A thick oxide film containing an element that can have multiple valences
And the oxide in the region where the oxide film is formed.
At least one of the critical temperature and the critical current density of the superconductor
The superconducting member is characterized in that at least one of input and output of electric power is performed in a region where the oxide superconductor has a large temperature and at least one of the critical temperature and the critical current density of the oxide superconductor is small.

The present invention also provides a step of preparing a solid raw material containing an element capable of having a plurality of valences, a step of heating the oxide superconductor to 500 ° C. or higher and 800 ° C. or lower, 0.01
Under the oxygen partial pressure of Torr or more and 2 Torr or less, the solid raw material is irradiated with a pulse laser in which a region having a fluence of 10% or more and 50% or less of the peak fluence is 10% or more and 70% or less of the total irradiation area, and the oxidation is performed. And a step of laminating an oxide film on the object superconductor.

Further, in the present invention , the solid raw material has at least an element capable of having a plurality of valences and an element bonded to the element capable of having a plurality of valences. Lower elements may be less than stoichiometric.
Here, the element that binds to the element having a plurality of valences may or may not be the element having a plurality of valences. Moreover, you may contain elements other than these two kinds of elements.

Further, according to the present invention , a step of preparing a solid raw material containing an element capable of having a plurality of valences, and a step of heating a substrate having an oxide superconductor formed on the surface thereof at 500 ° C. or higher and 800 ° C. or lower. And, under an oxygen partial pressure of 0.01 Torr or more and 2 Torr or less, the solid raw material is irradiated with a pulse laser in which a region having a fluence of 10% or more and 50% or less of the peak fluence is 10% or more and 70% or less of the entire irradiation area. , laminating an oxide film on the oxide superconductor, after the step of laminating the oxide film, characterized by comprising a step of laminating an oxide superconductor on a back surface of the substrate A method for manufacturing a superconducting member is provided.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have found that when an oxide film containing an element that can have multiple valences during film formation and that easily binds to oxygen is stacked on an oxide superconductor, It has been discovered that the critical temperature Tc and the critical current density Jc of the superconductor do not decrease or the degree of decrease decreases. For example
When a thin film of a material composed of an element that can have trivalent and tetravalent elements such as Ti is laminated on an oxide superconductor in an oxidizing atmosphere, 5
It has been found that the desorption of oxygen from the oxide superconductor, which is likely to occur during the process of surface coating performed at a high temperature of 00 ° C. or higher, can be prevented, and the critical temperature Tc does not decrease, but improves in some cases. Complex oxides such as SrTiO ₃ and YSZ are examples of oxide materials containing an element that can have multiple valences. Even when these films were produced by the vacuum process, it was confirmed that the critical temperature Tc and the critical current density Jc did not decrease.

In the case of YSZ, the smaller the amount of Y, the smaller the decrease in Tc. Therefore, the amount of Y is more than 0 mol% and 1 mol% or less, preferably 0.2 mol% or less. Also Sr
With TiO ₃ , the decrease in Tc can be reduced by increasing the amount of Ti deviated from the stoichiometric composition.

When the Ti / Sr ratio was 1.01 or more, Tc was improved by coating. In this case, the electrical characteristics are changed, and if the deviation is too large for application to the dielectric film of the high frequency device, the dielectric constant decreases and the dielectric loss increases, which is not preferable. If Ti / Sr exceeds 3, the environment resistance will not improve. The change in the dielectric constant with respect to the ratio of Ti and Sr is shown below.

[0017]

[Table 1]

For practical use, the decrease in the dielectric constant is desired to be at most 30% or less, preferably 20% or less. From this result, it is understood that Ti contained in the film is 1.5 times or less, preferably 1.1 times or less of Sr.

Further, in this material, it was also found that the environment resistance is improved, probably because a dense film is formed when Sr is increased. As a result of conducting an acceleration test in which a current that does not cause burnout is applied for 1 month in an environment of 30 ° C and 85% humidity, the J value of the sample covered with a film having a Sr / Ti ratio of 1.01 or more is shown.
The decrease in c (77K, 0T) was 10% or less. The decrease in Jc of the sample covered with the film having the ratio of 1.05 or more was 5% or less. However, this ratio is 1.
It is desired to be 5 or less, preferably 1.1 or less. Ti
The relationship between the / Sr ratio and the dielectric constant is shown in the table below.

[0020]

[Table 2]

Further, when the oxide material is composed of a plurality of elements capable of having a plurality of valences, if there is a deviation from the stoichiometric composition, there is an effect that Tc is not lowered even if either element is a large amount. However, experimental results have been obtained that the effect is greater when there are more elements that are more likely to bond with oxygen.

The deviation from the stoichiometric composition of the composite oxide can be expressed by the deviation from the stoichiometric ratio with respect to the total number of atoms excluding oxygen. For example, in the case of strontium titanate with a Ti / Sr ratio of 1.1, Ti: Sr = 1.05: 0.95 if the total of Ti and Sr is 2. Therefore Ti / (Ti + S
r) = 0.525 and the deviation from the stoichiometric ratio of 0.5 is 5%. According to this expression, the deviation from the preferable stoichiometric composition is 25% or less, preferably 5% or less. On the other hand, such a film can be produced by a method such as sputtering, MBE, CVD, or laser vapor deposition. As a method that is unlikely to cause deterioration of superconducting properties, CVD and laser vapor deposition with a high oxygen atmosphere during film formation are suitable. ing. Furthermore, laser deposition is most suitable because the growth temperature is low and waste gas treatment equipment is not required. Laser vapor deposition is a method in which a solid material called a target is irradiated with a pulsed laser having a short wavelength to evaporate it. Since the kinetic energy of the vaporized particles is very large, it is possible to form a dense film in a high oxygen atmosphere, which is not comparable to ordinary physical vapor deposition. If the laser used at this time has a distribution such that the fluence on the irradiated surface has a fluence region of 10% or more and 50% or less of the peak fluence in the area of 10% or more and 70% or less of the irradiation area, stoichiometry When a solid material having a composition is used, a film having more Ti than the stoichiometric composition is obtained. The principle is shown below.

When a solid substance is irradiated with a laser having a short wavelength such as an excimer laser, the electrons involved in the bond of the substance are excited and knocked out, so that the bond is broken. At this time, most of the constituent elements become ions. Then, they repel each other and jump off the surface of the solid, causing evaporation. In the vicinity of evaporation, a plasma in which these ions and electrons are present at high density is formed,
A considerable reaction heat is generated. However, such a phenomenon occurs when a laser having a fluence of a certain value or more is irradiated. When a laser with a fluence of less than that is irradiated, even if the bond is broken and the structure is broken, evaporation does not occur even if it is partial and the density is low. However, when the vapor pressure of the irradiated substance is high, the substance is easily thermally evaporated. When producing a film consisting of multiple elements with different vapor pressures, if the distribution of the fluence of the laser irradiated on the target has both the region above the threshold and the region below it, the laser with low fluence can be obtained. Only the element with high vapor pressure evaporates from the area irradiated by the heat of the plasma generated by the laser light above the threshold. Therefore, an element having a low vapor pressure remains on the target and a region where the composition is deviated on the surface is formed according to the fluence distribution of the irradiated laser. When the target is rotated during film formation, the composition-shifted region formed in this way is irradiated again with a laser having a fluence above the threshold, and the composition of the film can be shifted. . In this way, the element having a low vapor pressure can be contained in the film more than the target composition. On the other hand, when the target is irradiated with a laser having a uniform fluence and a threshold value or more, a film having the same composition as that of the target is obtained. Therefore, in order to obtain a film deviated from the stoichiometric composition, it is necessary to shift the target composition from the stoichiometric composition. Normal target is 10
It is produced by sintering at a high temperature of about 00 ° C, but depending on the material, a different phase precipitates, and if it grows to a size that cannot be ignored compared to the irradiation area per pulse of the laser, the evaporation composition at each pulse May change, which is not preferable. According to the manufacturing method of the present invention, a film having a desired composition can be obtained by controlling the fluence distribution of the laser without changing the target composition, which is preferable. The effects of laser fluence and irradiation area on the film composition, relative permittivity and critical temperature of the underlying oxide superconductor are shown below.

[0024]

[Table 3]

From this result, the fluence is 1 of the peak value.
The SrTiO ₃ film obtained when the area of 0% or more and 50% or less is 10% or more and 70% or less of the irradiation area is YB
It can be seen that a high critical temperature can be obtained when laminated on the CO film. These films have a Ti / Sr ratio of at least 1.
It is 01 or more and 1.10 or less, and when expressed as a deviation from the stoichiometric composition, it means that the film has a large amount of Ti in the range of 0.5% or more and 5% or less. When the film is manufactured under the conditions other than this range, there is a problem in productivity, whether any of the properties is not improved. For example, if the area of the region where the fluence is 0.2 or less of the peak exceeds the above range, the effect is small and the film formation rate becomes slow, and the productivity is lowered, which is not preferable. Further, when the area of the low fluence region is small, the effect is small and the effect of suppressing the decrease in Tc of the superconductor is exerted, but it is not improved.

On the surface of the oxide superconductor, titanium oxide or S which is an element capable of having a plurality of valences depending on the stoichiometric composition
An oxide material consisting of at least two kinds of elements selected from r, Ti, Ba, Pb, and Zr is laminated on a superconductor, and SrTiO ₃ , Ba having a stoichiometric composition or a composition close to it is formed on this film.
By stacking dielectrics such as TiO ₃ and PZT, the decrease in the dielectric constant is small and the decrease in Tc of the superconductor can be suppressed.
The film deposited on the surface of the oxide superconductor should be at least 10
0A or more, preferably 500A or more is necessary, and less than this is less effective. It is desirable that the upper limit is 5000 A or less, preferably 2000 A or less. On the other hand, the thickness of the dielectric film laminated on this film is determined by the capacitance of the device.

Sr of stoichiometric composition or composition close to it
In order to obtain a dielectric film such as TiO ₃ , BaTiO ₃ or PZT, a target having a composition with a lower vapor pressure than the desired film composition and a small number of elements is irradiated to a region where the fluence is 10% or more and 50% or less of the peak value. It can be manufactured by irradiating a pulsed laser having an area of 10% or more and 70% or less of the area.

Further, in the case of application to high frequency equipment, one side of a superconductor laminated on both sides of a substrate may be processed into a predetermined shape by photolithography, and a dielectric film may be laminated on the one side. It is difficult to process the filmed sample in steps such as resist coating and peeling, and there is a problem that the sample is scratched during processing and the yield is reduced. However, according to the present invention, the superconductor formed on only one surface of the substrate is processed, then the above oxide material or dielectric is laminated, and then the superconductor is formed on the back surface. Since the characteristics are not deteriorated, the productivity and the yield can be improved. Furthermore, it is preferable to stack the above-mentioned oxide material on the superconductor on the back surface because of excellent environmental resistance. Further, the area of the region where the oxide film is laminated on the superconductor needs to be larger than the area of the region where it is not laminated, and it is desired to be at least 2 times or more, preferably 10 times or more. If it is less than this range, the region where Jc is high is narrowed and the current that can be passed through the element is reduced, which is not preferable.

The oxide superconductor used in the present invention is Y
Not limited to BCO, Bi system and Tl system may be used. Examples of the present invention will be described below.

Example 1 A SrTiO ₃ single crystal substrate 2 is attached above a container 1 which can be kept under reduced pressure as shown in FIG. 1, and heated by a heater 3 to a desired temperature. Then, while introducing oxygen at a constant flow rate of 100 SCCM into the container 1, the exhaust speed of the exhaust pump 7 is adjusted to adjust the pressure to 0.01 T.
While maintaining a range of orr to 1.0 Torr, the average fluence of target 6, which is a solid raw material composed of Y, Ba, and Cu, is 1.
The raw material is evaporated by irradiating a laser beam of 0 J / cm ² or more to form a 1.0 μm thick Y-based superconductor film on the substrate.
As shown in FIG. 2, after the Y-based superconductor film 4 is processed by using the photolithography technique, the Y-based superconductor film 4 is mounted again in the film forming container and heated so as to be in the range of 500 ° C. to 800 ° C. At this time, if the temperature of the sample exceeds 400 ° C., it is preferable to introduce oxygen because oxygen is not desorbed from the processed superconductor. Also, the pressure may be the same as or higher than that when the superconductor is formed.

Next, a sintered target made of an oxide of Ti was irradiated with a laser having an average fluence of 0.6 J / cm ² or more to deposit a titanium oxide film 5 of 5000A. The Tc of this sample was 91 K, which was close to the original value of the Y-based superconductor, and it was confirmed that there was no deterioration in the coating process.

Example 2 As shown in FIG. 1, a SrTiO ₃ single crystal substrate 2 is attached above a container 1 which can be kept under reduced pressure, and heated to a desired temperature by a heater 3. Then, while introducing oxygen at a constant flow rate of 100 SCCM into the container 1, the exhaust speed of the exhaust pump 7 is adjusted to adjust the pressure to 0.01 T.
While maintaining a range of orr to 1.0 Torr, the average fluence of target 6, which is a solid raw material composed of Y, Ba, and Cu, is 1.
Laser light of 0 J / cm ² or more is irradiated to evaporate the raw material to form a substrate having a thickness of 1.0 μm.

Next, as shown in FIG. 2, after the Y-based superconductor film 4 is processed by using the photolithography technique, the Y-based superconductor film 4 is mounted again in the film forming container 1 and heated to a temperature in the range of 500 ° C. to 800 ° C. At this time, if the temperature of the sample exceeds 400 ° C., it is preferable to introduce oxygen because oxygen is not desorbed from the processed superconductor. Also, the pressure may be the same as or higher than that when the superconductor is formed.

Next, a sintered target 6 made of an oxide of Sr, Ti is irradiated with a laser having a fluence region of 40% with respect to a peak fluence of 1.0 J / cm ^{2 in} an area of 66% of the irradiation area. 5000A Ti is more than stoichiometric
A SrTiO ₃ film was laminated. The Tc of this sample was 91 K, which was close to the original value of the Y-based superconductor, and it was confirmed that there was no deterioration in the coating process.

(Embodiment 3) As shown in FIG. 1, a tape mainly made of silver and having a width of 10 mm is attached to the upper part of a container 1 which can be kept under reduced pressure so as to be movable in a longitudinal direction, and a heater 3 is heated to a desired temperature. To heat. Then container 1
While introducing oxygen at a constant flow rate of 100 SCCM, the exhaust speed of the exhaust pump 7 is adjusted to adjust the pressure from 0.01 Torr to 1.
While maintaining the range of 0 Torr, the target 6 which is a solid raw material composed of Y, Ba and Cu is irradiated with a laser beam having an average fluence of 1.0 J / cm ² or more to evaporate the raw material at a constant speed (1 cm / min). A Y-based superconductor film having a thickness of 1.0 μm is formed on the moving substrate 2.

Then, in the same container, a sintered body target 6 made of an oxide of Sr and Ti was irradiated with 1.
A laser having a fluence region of 40% with respect to a peak fluence of 0 J / cm ² was irradiated to continuously deposit a SrTiO ₃ film having a Ti content of 5000 A higher than the stoichiometric composition. The Tc of this sample is 91K, which is close to the original value of the Y-based superconductor,
It was confirmed that there was no deterioration in the coating process. When this sample was applied to power equipment as a superconducting wire, it showed good characteristics over a long period of time.

Example 4 As shown in FIG. 1, a LaAlO ₃ single crystal substrate 2 is attached above a container 1 which can be kept under reduced pressure, and heated to a desired temperature by a heater 3. Then, while introducing oxygen at a constant flow rate of 100 SCCM into the container 1, the exhaust speed of the exhaust pump 7 is adjusted to adjust the pressure to 0.01 T.
While maintaining a range of orr to 1.0 Torr, the average fluence of target 6, which is a solid raw material composed of Y, Ba, and Cu, is 1.
The raw material is evaporated by irradiating a laser beam of 0 J / cm ² or more to form a 1.0 μm thick Y-based superconductor film 4 on the substrate 2. This film is processed into a pattern as shown in FIG. 3 by using a photolithography technique, and then mounted again in the film forming container 1 and heated so as to be in the range of 500 ° C. to 800 ° C. At this time, if the temperature of the sample exceeds 400 ° C., it is preferable to introduce oxygen because oxygen is not desorbed from the processed superconductor, and the pressure may be the same as or higher than that at the time of film formation of the superconductor.

Next, a sintered body target 6 made of an oxide of Sr, Ti is irradiated with a laser having a fluence region of 40% with respect to a peak fluence of 1.0 J / cm _{2 in} an area of 66% of the irradiated area. Ti of 500A is 10% from stoichiometric composition
We deposited a large amount of SrTiO ₃ film, and further deposited 5000 A of SrTiO ₃ film having a stoichiometric composition close to the stoichiometric composition by using a target having a Sr content higher than the stoichiometric composition. The Tc of this sample was 91 K, which was close to the original value of the Y-based superconductor, and it was confirmed that there was no deterioration in the coating process. When this sample was used as a stripline type resonator, it showed a high Q value and showed good characteristics for a long period of time.

Example 5 In this example, Tc and Jc of the superconductor in the same plane were partially changed.
As shown in FIG. 4, if a SrTiO ₃ film having a Ti content higher than the stoichiometric composition is stacked on a part of the current path and then the whole is covered with an SrTiO ₃ film having a stoichiometric composition, Ti is Many SrT
The Tc of the portion where the iO ₃ film is laminated is high, and in many cases, Jc is also high. In this way, when the Tc portion of 87K and the portion of 91K were made in the same plane and used as a current limiting element, the impedance during operation was moderately moderated and no accident of burning occurred. It was The reason will be described below.

A current limiting element using a superconductor is inserted in series with a power supply system, and when a short circuit accident occurs somewhere and a current higher than the rated current (critical current) is about to flow, it shifts to normal conduction. To generate resistance. However, the resistance of the oxide superconductor in the normal conducting state is considerably larger than that of metal, and the resistance suddenly occurs during operation, which causes a problem that the impedance of the power supply system fluctuates drastically, and there are many accidents of burning out. However, as shown in FIG. 4, when there is a portion where Tc and Jc are low in the current path of the device, T
Although the region of low c is transferred, the resistance of this part is not so high, and the heat generated there spreads around and the quench is gradually propagated, so that the impedance generation is moderately moderated.

In order to form regions having different Tc and / or Jc, SrTiO ₃ is laminated only on a part of the region, and then it is vacuumed or in a rare gas atmosphere such as nitrogen or argon.
Oxygen may be desorbed from the region where SrTiO ₃ is not stacked by heating at 00 ° C. or higher. The difference between Tc and Jc can be controlled by the treatment temperature and / or the composition of the laminated SrTiO ₃ . Since the area of the region having a high Tc is not stacked due to the lamination, it is preferable that the area is larger than the area of the region having a low Tc, and at least 2 times or more and 1000 times or less, preferably 10
It is desired to be more than twice and less than 100 times.

If the area of the region having a high Tc is small, the current carrying capacity becomes small, which is not preferable. On the other hand, if the amount is too large, the effect of moderately easing the impedance generation during operation is reduced, which is not preferable.

As described above, the present invention is suitable for producing a superconducting member using a superconductor other than the current-limiting element, in which Tc and / or Jc are partially different in the same plane.

FIG. 5 shows a current control element according to the present invention.
As shown in the figure, a Y-based oxide superconducting material is formed on a substrate made of MgO, STO, or the like. A region of high Tc covered with STO and a region of low Tc not covered with STO are formed on the oxide superconducting material. An input current lead and an output current lead are respectively connected to the uncovered low Tc regions of the STO by a conductive material such as solder. The entire element is sealed with a sealing resin.

In this device, a region other than the current input part and the current output part is covered with an SrTiO ₃ film in which Ti is more than the stoichiometric composition or a SrTiO ₃ film having a stoichiometric composition, and then a current lead is attached. In the superconducting member thus manufactured, the Tc and / or Jc of the input / output portion of the electric current are low. Therefore, when superconducting is about to be quenched by an overcurrent or an external factor, it starts from here. Since this region is covered with a conductive material such as solder on the superconductor together with the current leads, it will not burn out due to heat generation by quenching if the contact resistance is small. Further, quenching with a small amount of current due to low Jc brings about the same effect. After that, the quench gradually propagates to other regions, so that it is prevented from being destroyed by burnout and discharge. To improve the environment resistance of the current lead portion, this portion or the whole may be sealed with resin or the like.

[0046]

As described above, the superconducting member and the method for producing the same according to the present invention can coat the surface without deteriorating the characteristics of the oxide superconductor, and exhibit good characteristics for a long period of time. It has the feature.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a laser deposition apparatus.

FIG. 2 is a sectional view of the superconducting member of the present invention.

FIG. 3 is a top view and a sectional view of a superconducting member of the present invention.

FIG. 4 is a top view and a sectional view of the superconducting member of the present invention.

FIG. 5 is a top view and a sectional view of the superconducting member of the present invention.

[Explanation of symbols] 1 ... Vapor deposition container 2 ... Substrate 3 ... heater 4 ... Oxide superconductor 5 ... Oxide film 6 ... Target 7 ... Exhaust pump

Continuation of front page (56) Reference JP-A-1-126205 (JP, A) JP-A-64-57767 (JP, A) JP-A-1-181444 (JP, A) JP-A-4-137677 (JP , A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 39/24 ZAA C01G 1/00 C04B 35/495 ZAA H01B 12/06 ZAA H01L 39/02 ZAA

Claims (6)

(57) [Claims] 1. An oxide superconductor, and an oxide film formed on the oxide superconductor, containing an element capable of having a plurality of valences, and deviating from the stoichiometric composition. Characteristic superconducting member. 2. An oxide superconductor, and an oxide film formed on a part of the oxide superconductor, containing an element capable of having a plurality of valences, and deviating from the stoichiometric composition. At least one of the critical temperature and the critical current density of the oxide superconductor in the region where the oxide film is formed is large. 3. A substrate, an oxide superconductor formed on the substrate, and 500 angstroms formed on a part of the oxide superconductor.
An element that can have multiple valences with a film thickness of more than strom
An oxide film containing the oxide film of the oxide superconductor in the region where the oxide film is formed.
At least one of the critical temperature and the critical current density is large,
A superconducting member, wherein at least one of input and output of electric power is performed in a region where at least one of critical temperature and critical current density of the oxide superconductor is small. 4. A step of preparing a solid raw material containing an element capable of having a plurality of valences, a step of heating an oxide superconductor to 500 or more and 800 or less, and an oxygen partial pressure of 0.01 Torr or more and 2 Torr or less. ,
The solid raw material is irradiated with a pulse laser in which a region having a fluence of 10% or more and 50% or less of the peak fluence is 10% or more and 70% or less of the total irradiation area, and an oxide film is laminated on the oxide superconductor. And a step of manufacturing a superconducting member. Wherein said solid material has an element that can take the number plurality of valence has at least an element that binds to the plurality of valences the possible elements, low elemental vapor pressure of the element is chemically The method for producing a superconducting member according to claim 7, wherein the superconducting member is less than the stoichiometric composition. 6. A step of preparing a solid raw material containing an element capable of having a plurality of valences, and a substrate having an oxide superconductor formed on its surface is 500 or more 8
Heating to 00 or less, and under an oxygen partial pressure of 0.01 Torr or more and 2 Torr or less,
The solid raw material is irradiated with a pulse laser in which a region having a fluence of 10% or more and 50% or less of the peak fluence is 10% or more and 70% or less of the total irradiation area, and an oxide film is laminated on the oxide superconductor. process and, after the step of laminating the oxide film, method of manufacturing a superconducting member, characterized by comprising a step of laminating an oxide superconductor on a back surface of the substrate.