JP2017091680A - Thin film oxide superconducting wire material and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thin film oxide superconducting wire material capable of easily securing conductivity between an oxide superconducting layer and a metal substrate by a layer other than an intermediate layer instead of a stabilizing layer causing cost up or increase of wire material size and a manufacturing method therefor.SOLUTION: There is provided a manufacturing method of a thin film oxide superconducting wire material for manufacturing the thin film oxide superconducting wire material by cutting the thin film oxide superconducting wire material having a REBaCuO-based oxide superconducting layer formed on a belt-like metal substrate via an intermediate layer in a longitudinal direction, the method having a thermally cutting process for thermally cutting the thin film oxide superconducting wire material in the longitudinal direction by applying an infrared laser to cut locations, wherein, by thermally cutting the thin film oxide superconducting wire material in the thermally cutting process, a mixed layer in which a material constituting the thin film oxide superconducting wire material melted when cut is solidified is formed on both side surfaces of the cut thin film oxide superconducting wire material as a conductive layer electrically connecting the oxide superconducting layer and the metal substrate.SELECTED DRAWING: None

Description

  The present invention relates to a thin-film oxide superconducting wire in which a superconducting layer made of an oxide superconductor is provided on a band-shaped metal substrate, and a method for manufacturing the same.

A thin-film oxide superconducting wire provided with a superconducting layer made of an oxide superconductor having a transition temperature (Tc) higher than the liquid nitrogen temperature is generally an intermediate layer on a metal substrate having a width of about 1 to 10 cm. It is manufactured by sequentially forming a REBa ₂ Cu ₃ O _7-x (RE: rare earth element) -based oxide superconducting layer and a silver layer as a protective layer, and then cutting into a predetermined wire width suitable for the application. Yes.

  At this time, in order to ensure stability during energization, the outer periphery of the thin-film oxide superconducting wire after cutting is usually plated with copper (see FIG. 6), or a copper tape is attached to the upper surface of the oxide superconducting layer. (See FIG. 7), a stabilization layer is formed (Patent Documents 1 and 2). 6 and 7, 51 is a thin film oxide superconducting wire, 2 is a metal substrate, 3 is an intermediate layer, 4 is an oxide superconducting layer, 5 is a protective layer, and 9 is a stabilization layer.

  In addition, instead of forming such a stabilization layer, it is conceivable to ensure the stability when the metal substrate is energized by providing conductivity between the oxide superconducting layer and the metal substrate. Has proposed that the above-described intermediate layer be formed of a conductive material (Patent Documents 3 to 5, Non-Patent Document 1).

Japanese Patent Application Laid-Open No. 2012-156048 JP 07-037444 A JP 2005-044636 A US Pat. No. 6,617,283 US Pat. No. 6,956,010

T. Aytag et al., Electrical and Magnetic Properties of Conductive Copper-Coated Conductors, Applied Physics Letters, APPS American Institute of Physics, November 10, 2003, Volume 83 (VOLUME 83), No. 19 (NUMBER 19), pages 3963-3965

  However, forming the stabilization layer by copper plating or affixing a copper tape not only increases the cost, but also increases the size of the wire.

  When the intermediate layer is formed of a conductive material, the intermediate layer has a conventional role of preventing element diffusion into the superconducting layer and lattice matching with the superconducting layer, and further, between the superconducting layer and the metal substrate. A new role of ensuring conductivity will be added. It is not easy to find an intermediate layer material that has such characteristics that can sufficiently fulfill such various roles and is easy to form.

  Therefore, the present invention can easily secure the conductivity between the oxide superconducting layer and the metal substrate in a layer other than the intermediate layer, instead of the stabilization layer that causes an increase in cost and an increase in wire size. It is an object to provide a thin film oxide superconducting wire and a method for manufacturing the same.

A method for producing a thin film oxide superconducting wire according to an aspect of the present invention is as follows.
A thin-film oxide superconducting wire in which a REBa ₂ Cu ₃ O _7-x (RE: rare earth element) -based oxide superconducting layer is formed on a strip-shaped metal substrate via an intermediate layer is cut in the longitudinal direction to obtain a desired A manufacturing method of a thin film oxide superconducting wire for manufacturing a thin film oxide superconducting wire having a width,
It comprises a thermal cutting step of irradiating the cut portion with an infrared laser to thermally cut the thin film oxide superconducting wire in the longitudinal direction,
In the thermal cutting step, by thermally cutting the thin film oxide superconducting wire, the material constituting the thin film oxide superconducting wire melted at the time of cutting is solidified on both side surfaces of the cut thin film oxide superconducting wire. It is a manufacturing method of the thin film oxide superconducting wire which forms a mixed layer as a conductive layer which electrically connects the oxide superconducting layer and the metal substrate.

The thin film oxide superconducting wire according to one aspect of the present invention is
A thin-film oxide superconducting wire in which a REBa ₂ Cu ₃ O _7-x (RE: rare earth element) -based oxide superconducting layer is formed on a band-shaped metal substrate via an intermediate layer,
A thin film oxide superconducting wire in which a mixed layer in which a material constituting the thin film oxide superconducting wire is solidified is formed as a conductive layer electrically connecting the oxide superconducting layer and the metal substrate on both sides. is there.

  According to the present invention, the conductivity between the oxide superconducting layer and the metal substrate can be easily ensured by a layer other than the intermediate layer in place of the stabilization layer that causes an increase in cost and an increase in wire size. A thin-film oxide superconducting wire and a method for manufacturing the same can be provided.

It is sectional drawing which shows the structure of the thin film oxide superconducting wire which concerns on 1st Embodiment. It is sectional drawing which shows the structure of the thin film oxide superconducting wire which concerns on 2nd Embodiment. It is sectional drawing which shows the structure of the thin film oxide superconducting wire which concerns on 3rd Embodiment. It is sectional drawing which shows the structure of the thin film oxide superconducting wire which concerns on 4th Embodiment. It is sectional drawing which shows the structure of the thin film oxide superconducting wire which concerns on 5th Embodiment. It is sectional drawing which shows an example of a structure of the conventional superconducting wire. It is sectional drawing which shows another example of a structure of the conventional superconducting wire.

[Description of Embodiments of the Present Invention]
First, embodiments of the present invention will be listed and described.

(1) A method for producing a thin film oxide superconducting wire according to an aspect of the present invention includes:
A thin-film oxide superconducting wire in which a REBa ₂ Cu ₃ O _7-x (RE: rare earth element) -based oxide superconducting layer is formed on a strip-shaped metal substrate via an intermediate layer is cut in the longitudinal direction to obtain a desired A manufacturing method of a thin film oxide superconducting wire for manufacturing a thin film oxide superconducting wire having a width,
It comprises a thermal cutting step of irradiating the cut portion with an infrared laser to thermally cut the thin film oxide superconducting wire in the longitudinal direction,
In the thermal cutting step, by thermally cutting the thin film oxide superconducting wire, the material constituting the thin film oxide superconducting wire melted at the time of cutting is solidified on both side surfaces of the cut thin film oxide superconducting wire. It is a manufacturing method of the thin film oxide superconducting wire which forms a mixed layer as a conductive layer which electrically connects the oxide superconducting layer and the metal substrate.

  While examining the solution of the above-mentioned problem, the present inventor observed a section of a thin-film oxide superconducting wire thermally cut by irradiating an infrared laser, and found a new layer on both side surfaces which are cut surfaces. Noticed that may have formed. On the other hand, such a layer was not formed in the case of a method of mechanically cutting using a slitter or the like or a method of cutting by irradiation with an ultraviolet laser.

  And when the material which comprises this layer was analyzed, the rare earth elements, such as copper, silver, iron, nickel, barium, Gd, etc. were mainly detected, and this layer is the thermal cutting which irradiates an infrared laser It turned out that it was the layer formed by solidifying the material which comprises the thin-film oxide superconducting wire which melt | dissolved occasionally, ie, metal substrate material, oxide superconducting layer material, and protective layer material as a mixture.

  Further, when the electrical resistance between the oxide superconducting layer on the front surface side and the metal substrate side on the back surface of the thin film oxide superconducting wire formed with such a layer was measured, it was as low as 2Ω or less per 1 cm of the wire length. And was found to have sufficient electrical conductivity. The reason why such a low electric resistance is obtained is presumed that this layer is made of a material constituting the thin film oxide superconducting wire as described above.

  This embodiment is based on the above knowledge, and by forming such a conductive layer, it is possible to ensure stability during energization without providing a stabilization layer. Such a conductive layer may be formed at the time of thermal cutting by irradiating an infrared laser, so that it is not necessary to add a role of an intermediate layer, and an oxide superconducting layer and a metal substrate can be easily formed. Can be ensured.

  And since there is no need to provide a stabilizing layer, the cost can be reduced and the size of the thin film oxide superconducting wire can be made compact, and the equipment using the thin film oxide superconducting wire can also be made compact. can do.

  Further, by ensuring the conductivity between the oxide superconducting layer and the metal substrate, a thickness of 1 μm or less is sufficient even when a silver layer is provided as a protective layer on the oxide superconducting layer as in the prior art. There is no need to provide it, and the cost can be reduced also from this aspect.

  Note that the conductive layer described above may include a material constituting the intermediate layer. Originally, since the intermediate layer is ceramic, it does not have conductivity, but since the thickness is small, the amount contained in the conductive layer is small, and the conductivity is not hindered.

(2) It is preferable that the thermal cutting is performed by irradiating the infrared laser from the metal substrate side and blowing an assist gas from the metal substrate side toward the cutting portion.

  By irradiating the infrared laser from the metal substrate side, the metal substrate material is first melted, so that a conductive layer having a smooth surface can be formed on the side surface. At this time, it is preferable to spray the assist gas together because the melted materials can be evenly dispersed.

(3) The thin film oxide superconducting wire after cutting is preferably heat-treated in an oxygen gas atmosphere.

  In the case of thermal cutting with an infrared laser, oxygen may escape from the oxide superconductor due to temperature rise at the time of cutting, leading to deterioration of superconducting properties. By performing the heat treatment therein, the escaped oxygen is again taken into the oxide superconductor, and the lowered superconducting characteristics can be sufficiently recovered.

(4) It is preferable to further form a protective layer on the oxide superconducting layer of the thin film oxide superconducting wire after cutting or on the outer periphery of the thin film oxide superconducting wire after cutting.

  By forming the protective layer, the oxide superconducting layer can be prevented from being mechanically damaged or damaged by moisture in the air. At this time, since the stability during energization is already ensured by the conductive layer on the side surface, the protective layer does not require conductivity as in the conventional silver layer.

(5) It is preferable to further form an insulating layer on the outer periphery of the thin film oxide superconducting wire after cutting.

  By forming the insulating layer, sufficient insulation can be secured when the thin-film oxide superconducting wire is used in a device.

(6) The thin film oxide superconducting wire according to one aspect of the present invention is
A thin-film oxide superconducting wire in which a REBa ₂ Cu ₃ O _7-x (RE: rare earth element) -based oxide superconducting layer is formed on a band-shaped metal substrate via an intermediate layer,
A thin film oxide superconducting wire in which a mixed layer in which a material constituting the thin film oxide superconducting wire is solidified is formed as a conductive layer electrically connecting the oxide superconducting layer and the metal substrate on both sides. is there.

  As described above, when the mixed layer in which the material constituting the thin film oxide superconducting wire is solidified on both sides is formed as a conductive layer that electrically connects the oxide superconducting layer and the metal substrate, it is stable. Since the stability at the time of energization can be ensured without providing a layer, it is possible to provide a thin-film oxide superconducting wire that is compact and excellent in superconducting properties at a low cost.

(7) The electrical resistance between the oxide superconducting layer or the silver layer provided on the oxide superconducting layer and the metal substrate is preferably 2Ω or less per 1 cm of wire length.

  As described above, when the electrical resistance is a low value of 2Ω or less per 1 cm of the length of the wire, sufficient electrical conductivity is ensured and stability during energization is secured.

(8) It is preferable that the metal substrate has at least a good conductor portion continuous in the longitudinal direction.

  By using a metal substrate having a good conductor in this way, an overcurrent can be efficiently passed from the side conductive layer to the metal substrate, and the role of the stabilizing layer can be appropriately assigned to the metal substrate. Can do. Examples of such metal substrates include oriented metal substrates such as nickel and Ni-W alloys, Ni-based heat-resistant alloy substrates such as Hastelloy, clad substrates having a copper layer as an orientation layer, and SUS. Since the clad substrate has a copper layer having a small electric resistance in the metal substrate, the effect of stabilization is remarkably exhibited.

(9) It is preferable that the thin film oxide superconducting wire has an oxide superconducting layer formed on both sides with an intermediate layer sandwiched between the metal substrates.

  By forming the oxide superconducting layers on both surfaces of the metal substrate, the performance of the thin film superconducting wire can be improved, and a thin film oxide superconducting wire excellent in superconducting characteristics with higher Ic can be provided.

[Details of the embodiment of the present invention]
A thin film oxide superconducting wire according to an embodiment of the present invention and a manufacturing method thereof will be described below with reference to the drawings. In addition, this invention is not limited to these illustrations, is shown by the claim, and intends that all the changes within the meaning and range equivalent to a claim are included.

(First embodiment)
[1] Thin-film oxide superconducting wire Configuration of Thin-Film Oxide Superconducting Wire First, the configuration of the thin-film oxide superconducting wire according to the first embodiment will be described. FIG. 1 is a cross-sectional view showing the configuration of the thin film oxide superconducting wire according to the first embodiment.

  In the thin film oxide superconducting wire 1 shown in FIG. 1, an intermediate layer 3, an oxide superconducting layer 4, an oxide superconducting layer 4 and a protective layer 5 are formed on a metal substrate 2 in this order.

On the side surface of the thin film oxide superconducting wire 1, a metal substrate 2 melted by heat at the time of thermal cutting, an intermediate layer 3, an oxide superconducting layer 4 of REBa ₂ Cu ₃ O _7-x (RE: rare earth element), protection A conductive layer 7 in which the layer 5 (silver layer) is cooled and solidified is formed. Therefore, the conductive layer 7 is formed from the material of the metal substrate 2, the material of the intermediate layer 3, the material of the oxide superconducting layer 4, and the material in which silver is mixed, and has sufficient conductivity. The conductive layer 7 electrically connects the protective layer 5 and the oxide superconducting layer 4 to the metal substrate 2 as shown in FIG.

2. Method for Producing Thin Film Oxide Superconducting Wire The thin film oxide superconducting wire having the above structure is produced according to the following procedure.

(1) Production of thin-film oxide superconducting wire before cutting First, a thin-film oxide superconducting wire before cutting is produced by a known method.

(A) Preparation of a superconducting layer formation base First, as a superconducting layer formation base, an intermediate layer for suppressing element diffusion from a metal substrate is formed on a band-shaped metal substrate cut into a predetermined width. Prepare the groundwork. At this time, at least the outermost surface needs to be biaxially oriented in order to give orientation to the superconducting layer. As an example of a preferred base for forming a superconducting layer, a ceramic layer in which orientation is further inherited on a clad substrate in which a copper layer biaxially oriented on a stainless tape and a nickel layer formed by inheriting the orientation of the copper layer are laminated. There may be mentioned a tape in which (stabilized zirconia such as CeO ₂ or YSZ, Y ₂ O ₃ or the like) is formed as an intermediate layer.

(B) Formation of oxide superconducting layer Next, on the intermediate layer, a known method such as a pulse laser deposition (PLD) method or a coating pyrolysis method (MOD method) is used to make REBa ₂ Cu ₃ O _{7- An x-} based oxide superconducting layer is formed. Here, RE is a rare earth element and includes yttrium (Y), ytterbium (Yb), gadolinium (Gd), samarium (Sm), neodymium (Nd), erbium (Er), europium (Eu), holmium (Ho), It is appropriately selected from dysprosium (Dy).

(C) Formation of Silver Layer Next, if necessary, a silver layer as a protective layer is formed on the oxide superconducting layer by using a vapor deposition method such as a DC sputtering method. In addition, in the case of the thin oxide superconducting wire which is not cut normally, this silver layer is formed with a thickness of several μm to several tens of μm in order to protect the oxide superconducting layer and stabilize the current. In this embodiment, since the silver layer is formed only for protecting the oxide superconducting layer and does not need to stabilize the current, the thickness of the silver layer can be reduced to 1 μm or less.

(D) Oxygen annealing (introducing oxygen into the oxide superconducting layer)
Next, heat treatment is performed in an oxygen atmosphere to introduce oxygen into the oxide superconducting layer. Thus, the production of the thin film oxide superconducting wire before cutting is completed.

(2) Thermal cutting process The thin-film oxide superconducting wire before cutting produced in the above is thermally cut in the longitudinal direction with a predetermined width using an infrared laser. At this time, the portion irradiated with the infrared laser is melted by heat, and the material of the metal substrate, the intermediate layer, the oxide superconducting layer, and the silver layer (as described above, the silver layer may not be formed) A melt with a mixture of is produced. The melt adheres so as to cover the side surface of the thin-film oxide superconducting wire generated by thermal cutting, and is then cooled and solidified. As a result, as shown in FIG. 1, conductive layers 7 each having a thickness of about 0.01 mm are formed on both side surfaces, and the distance between the oxide superconducting layer 4 and the metal substrate 2 is 2Ω or less per 1 cm length of the thin film oxide superconducting wire. The electrical resistance is electrically connected.

  As the infrared laser used for thermal cutting, a fiber laser or YAG laser capable of infrared light having a wavelength of about 1.0 to 1.1 μm is preferable. A continuous wave laser or a pulsed laser may be used. However, in the case of an ultrashort pulse laser, a non-thermal cutting ablation process is performed instead of a thermal cutting process, and a conductive layer is not formed. Also, an ultraviolet laser is not preferable because it is similarly ablated.

At the time of this cutting, it is preferable to irradiate an infrared laser in the direction of the oxide superconducting layer 4 from the metal substrate 2 side and to spray an assist gas toward the cutting portion. Specific examples of the assist gas include nitrogen (N ₂ ) gas.

  In addition, it is preferable that the irradiation conditions of the infrared laser other than the above-described wavelength are an output of 50 W or more and a focused diameter of 50 μm or less. By conducting a thermal cutting process under such irradiation conditions, the conductive layer 7 can be reliably formed simultaneously with the cutting.

(3) Oxygen heat treatment step Next, the thin film oxide superconducting wire cut by an infrared laser is subjected to heat treatment in an oxygen gas atmosphere. Thereby, oxygen cut out from the oxide superconductor is taken in again at the time of cutting, and the reduced superconducting characteristics are recovered, and the electrical resistance between the oxide superconducting layer and the metal substrate is further reduced, which is preferable.

  This heat treatment in oxygen is usually performed in pure oxygen at 1 atm, but may be performed under pressure. The treatment temperature may be 800 ° C. or lower. However, when the temperature is low, a long time treatment is required, and when the temperature is high, the effect is saturated. Therefore, the maximum temperature is preferably about 400 to 550 ° C.

  Specifically, after heating to the above treatment temperature and holding for a predetermined time, it is gradually cooled. Slow cooling is usually performed by furnace cooling, but the time required for slow cooling varies depending on the type of RE and is appropriately set. For example, in the case of an oxide superconductor in which Y is used as RE, there is no problem even if it is cooled to room temperature in a few minutes, but in the case of Gd, it is preferable to slowly cool to 200 ° C. over at least 2 hours. The present inventor has confirmed that the degree of recovery of Ic is improved.

  In addition, when the width | variety of the thin film oxide superconducting wire 1 is 1 mm or less, an Ic recovery effect is exhibited notably. Moreover, a thin film oxide superconducting wire which is rich in flexibility and suitable for bending and twisting can be obtained.

(Second Embodiment)
Next, a second embodiment will be described.

  FIG. 2 is a cross-sectional view showing the configuration of the thin film oxide superconducting wire according to the second embodiment.

  The thin film oxide superconducting wire 11 according to the second embodiment is a thin film oxide according to the first embodiment in that the protective layer 5 formed on the thin film oxide superconducting wire 1 according to the first embodiment is not provided. This is different from the superconducting wire 1.

  Since the conductive layer 7 electrically connects the oxide superconducting layer 4 and the metal substrate 2, it is not necessary to provide a conductive material on the oxide superconducting layer 4, and a silver layer using expensive silver is not required. The provision can be omitted. Thereby, the cost which manufactures the thin film oxide superconducting wire 11 can further be reduced.

(Third embodiment)
Next, a third embodiment will be described.

  FIG. 3 is a cross-sectional view showing the configuration of the thin film oxide superconducting wire according to the third embodiment.

  The thin film oxide superconducting wire 21 according to the third embodiment is a thin film according to the second embodiment in that a clad type metal substrate is used as the metal substrate of the thin film oxide superconducting wire 11 according to the second embodiment. This is different from the oxide superconducting wire 1.

  Since the clad type metal substrate is formed by providing a copper layer 6 having excellent conductivity as an alignment layer on a base 2a made of SUS or the like as a base metal, the thin film oxide superconducting wire 21 of the conductive layer 7 is formed. The effect of overcurrent countermeasures during energization can be further improved.

(Fourth embodiment)
Next, a fourth embodiment will be described.

  FIG. 4 is a cross-sectional view showing the configuration of the thin film oxide superconducting wire according to the fourth embodiment.

  The thin film oxide superconducting wire 31 according to the fourth embodiment is the third point in that an insulating protective layer 8 is provided on the oxide superconducting layer 4 of the thin film oxide superconducting wire 21 according to the third embodiment. This is different from the thin film oxide superconducting wire 21 according to the embodiment.

  By providing the insulating protective layer 8 on the oxide superconducting layer 4, it is possible to prevent the superconducting layer from being mechanically damaged or damaged by moisture in the air. Since the conductive layer 7 is formed at this time, it is possible to take measures against overcurrent when the thin-film oxide superconducting wire 31 is energized. Therefore, the conductivity of the protective layer 8 is unnecessary, and an expensive material such as silver is used. It is also possible to use an insulating material as the protective layer 8, and the manufacturing cost of the thin film oxide superconducting wire 31 can be reduced.

(Fifth embodiment)
Next, a fifth embodiment will be described.

  FIG. 5 is a cross-sectional view showing a configuration of a thin film oxide superconducting wire according to the fifth embodiment.

  The thin film oxide superconducting wire 41 according to the fifth embodiment is a thin film oxide superconducting wire according to the third embodiment in that the periphery of the thin film oxide superconducting wire 21 according to the third embodiment is covered with the insulating layer 10. 21.

  When the thin-film oxide superconducting wire 41 is used in equipment, the periphery of the thin-film oxide superconducting wire 41 is often insulated, but when the oxide superconducting layer 4 or the conductive layer 7 is directly covered by the insulating layer 10, The manufacturing cost can be further reduced.

  The insulating layer 10 is preferably made of enamel, polyamide resin or the like that is generally widely used.

[Experimental example]
Next, the present invention will be described more specifically based on experimental examples.

  In the following, the thin film oxide superconducting wire is cut using different cutting methods, specifically, cutting with an infrared laser, and cutting with an ultraviolet laser, and in the cases of Experimental Examples 1 to 4 with and without heat treatment in oxygen. A thin-film oxide superconducting wire was prepared, and the Ic of each thin-film oxide superconducting wire was measured, and the electrical resistance between the surface oxide superconducting layer side and the back metal substrate side was measured with a conductive layer. .

(1) Preparation of thin-film oxide superconducting wire before cutting A clad plate in which an oriented Cu layer and an oriented Ni layer are laminated on a SUS base material is prepared as a metal substrate, and Y ₂ O ₃ , An intermediate layer in which YSZ and CeO ₂ were laminated was formed. Then, a GdBa ₂ Cu ₃ O _7-x oxide superconducting layer is formed on the intermediate layer as an oxide superconducting layer, and a silver layer serving as a protective layer is formed on the oxide superconducting layer. A thin film oxide superconducting wire was prepared.

(2) Cutting conditions The produced thin-film oxide superconducting wire having a width of 10 mm is thermally cut using an infrared laser in Experimental Examples 1 and 2, and non-thermal cutting is performed using an ultraviolet laser in Experimental Examples 3 and 4. went.

  The cutting conditions using the above-described infrared laser were set as follows. Note that the cut width was 1.5 mm, 4 mm, 2 mm, 1 mm, and 1.5 mm from the end, and a thin film oxide superconducting wire cut to 4 mm was used for subsequent measurements.

Laser: Fiber laser Wavelength: 1.064 μm
Output: 300W
Assist gas: N ₂
Processing speed: 50 m / min

  Moreover, the cutting conditions by the ultraviolet laser were set as follows. The cut width was 3 mm, 4 mm, and 3 mm from the end, and a thin film oxide superconducting wire cut to 4 mm was used for the subsequent measurement.

Laser: YAG laser triple wave Wavelength: 0.355 μm
Output: 4W
Assist gas: None Processing speed: 6 mm / min

(3) Heat treatment in oxygen Two wire samples were cut out from the thin film oxide superconducting wire after cutting to a width of 4 mm, and one of them (Experimental Examples 1 and 3) was 550 in a pure oxygen gas atmosphere at 1 atmosphere. After raising the temperature to 0 ° C., the temperature was maintained for 30 minutes, and then a heat treatment in oxygen was performed by gradually cooling by furnace cooling.

(4) Measurement of electric resistance When the cross section of the wire sample (Experimental Example 1) thermally cut by the infrared laser was observed, the side surface was covered with a layer of about 0.01 mm. From this layer, mainly Cu, Ag, Fe, Ni, Ba, Gd and the like were detected. From this result, it was found that this layer was formed by the mixture of the material of the metal substrate melted by heat, the material of the oxide superconducting layer, and the silver of the silver layer during thermal cutting with an infrared laser. .

  And when the electrical resistance of the front surface side and the back surface side of this wire sample was measured, it was 1.1Ω per 1 cm of wire length without heat treatment in oxygen (Experimental Example 1), and per 1 cm of wire length when there was (Experimental Example 2). It was 0.4Ω, and it was confirmed that this layer had sufficient conductivity. On the other hand, it was confirmed that a wire sample (Experimental Example 3) thermally cut by an ultraviolet laser in which such a layer was not formed showed a large resistance of 1200Ω per 1 cm of the wire length.

(5) Measurement of Ic The critical current (Ic) of each wire sample was measured in liquid nitrogen using a four-terminal method. Moreover, normalized Ic (A / cm) was calculated for each experimental example based on the measurement results. The results are shown in Table 1.

  From Table 1, in the wire sample thermally cut by the infrared laser, the Ic lowered by the heat treatment in oxygen is recovered, and a high Ic is obtained. The low Ic is reduced by this high Ic. It was confirmed that this occurred.

  The thin-film oxide superconducting wire of the present invention and the manufacturing method thereof can reduce the cost of forming the stabilization layer, have an overcurrent countermeasure, and can be easily manufactured. It is useful for the provided thin film oxide superconducting wire and its manufacturing method.

1, 11, 21, 31, 41, 51 Thin-film oxide superconducting wire 2 Metal substrate 2a Base 3 Intermediate layer 4 Oxide superconducting layer 5, 8 Protective layer 6 Copper layer 7 Conductive layer 9 Stabilizing layer 10 Insulating layer

Claims (9)

A thin-film oxide superconducting wire in which a REBa ₂ Cu ₃ O _7-x (RE: rare earth element) -based oxide superconducting layer is formed on a strip-shaped metal substrate via an intermediate layer is cut in the longitudinal direction to obtain a desired A manufacturing method of a thin film oxide superconducting wire for manufacturing a thin film oxide superconducting wire having a width,
It comprises a thermal cutting step of irradiating the cut portion with an infrared laser to thermally cut the thin film oxide superconducting wire in the longitudinal direction,
In the thermal cutting step, by thermally cutting the thin film oxide superconducting wire, the material constituting the thin film oxide superconducting wire melted at the time of cutting is solidified on both side surfaces of the cut thin film oxide superconducting wire. The manufacturing method of the thin film oxide superconducting wire which forms a mixed layer as a conductive layer which electrically connects the said oxide superconducting layer and the said metal substrate.   2. The method of manufacturing a thin film oxide superconducting wire according to claim 1, wherein the thermal cutting is performed by irradiating the infrared laser from the metal substrate side and spraying an assist gas from the metal substrate side toward a cutting portion. .   The method for producing a thin-film oxide superconducting wire according to claim 1 or 2, wherein the thin-film oxide superconducting wire after cutting is then heat-treated in an oxygen gas atmosphere.   4. The protective layer is further formed on the oxide superconducting layer of the thin-film oxide superconducting wire after cutting, or on the outer periphery of the thin-film oxide superconducting wire after cutting. The manufacturing method of the thin film oxide superconducting wire described in 1.   The manufacturing method of the thin film oxide superconducting wire according to any one of claims 1 to 4, wherein an insulating layer is further formed on the outer periphery of the thin film oxide superconducting wire after cutting. A thin-film oxide superconducting wire in which a REBa ₂ Cu ₃ O _7-x (RE: rare earth element) -based oxide superconducting layer is formed on a band-shaped metal substrate via an intermediate layer,
A thin film oxide superconducting wire in which a mixed layer in which a material constituting the thin film oxide superconducting wire is solidified is formed on both sides as a conductive layer that electrically connects the oxide superconducting layer and the metal substrate.   The thin film oxide superconductor according to claim 6, wherein an electrical resistance between the oxide superconducting layer or the silver layer provided on the oxide superconducting layer and the metal substrate is 2 Ω or less per 1 cm of wire length. wire.   The thin film oxide superconducting wire according to claim 6 or 7, wherein the metal substrate has at least a good conductor portion continuous in a longitudinal direction.   The thin film oxide superconducting wire according to any one of claims 6 to 8, wherein an oxide superconducting layer is formed on both surfaces via an intermediate layer with the metal substrate interposed therebetween.

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