JPH0362978A - Method of producing oxide superconductor circuit - Google Patents

Abstract

PURPOSE:To enable an oxide superconductor circuit to be produced easily without deteriorating characteristics by irradiating laser to an oxide superconductor and by changing the quality of a part to be exposed to light into a non- superconductive phase thus forming a circuit. CONSTITUTION:When forming a non-superconductive phase of specified shape at a specified part of an oxide superconductive formed body, CO2 gas laser, YAG laser, etc., are used for that part and the beam spot diameter and power of the laser beam are adjusted and light is irradiated, thus enabling that part to be subjected to thermal decomposition or fusion for forming a non- superconductive phase of desired shape, and superconductive current is interrupted. Namely, the formed body is not cut off completely but the quality is partially changed without losing the junction force at that part. Thus, intensity, etc., preserved by the oxide superconductor formed body itself does not change at all. Also, there is no need to worry about deteriorating characteristics of superconductive phase other than the part to be subjected to laser beam.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field The present invention relates to a method for producing oxide, Ifl electrically conductive conductive tracks by laser irradiation.

(B) Prior Art Conventionally, there are various methods for once producing an oxide superconducting molded body and converting a part of it into a non-superconducting phase. there were. That is, (a) a predetermined shape of a non-a
A method of processing the superconducting molded body and using a non-superconducting substance as a bonding agent to bond the bonded parts to form a non-conducting phase in order to produce a conductive phase.

For example, a notch is formed in a part of each ring, and several superconductor rings with slits made so that no circular current flows through the rings are stacked together to form a coil shape, and a superconducting current is passed through the ring. For this purpose, a''Yf, 4 powder is used as a bonding material to form a bond so that a superconducting current flows, and the other contact parts between each ring are bonded with a non-superconducting material to form a non-, TFL conducting phase. The a electric field 71! current is prevented from flowing by forming a superconducting current 71!.Thus, the superconducting '\L current flows from one end of the coil to the other end.

In the case of method (a), a non-superconducting phase is formed at the joint between superconducting molded bodies, but this method is time-consuming because it cannot be integrally molded, and it is extremely difficult to create a high-performance circuit. .

(b) When forming a non-superconducting phase of a predetermined shape in a desired part of an oxide superconducting I&type body, a thin film of Fe or Co is formed in the part where the non-15 conducting phase is desired, and the superconducting phase in the part is formed by thermal diffusion. Method of destruction to form a non-tfl conductive phase.

In this method (b), a non-superconducting phase is formed by diffusion of Fe or Co, but since it is necessary to observe the diffusion state in a cross section during the fabrication process, it is difficult to form a complete non-superconducting phase. It requires a long time and is difficult to manufacture with high precision.

(c) When forming a non-superconducting phase in a superconducting oxide molded body, after applying a resist to the surface of the molded body, peeling off the resist only in a predetermined portion and etching it with an acid or alkaline solution to dissolve it. A method of interrupting the conductive current by a' and y.

As described above, this method (c) involves etching with an acid or alkaline solution, and therefore has drawbacks such as the solution penetrating into the molded body and deteriorating the superconducting properties.

(C) Disclosure of the Invention The present invention is a completely new method for manufacturing a circuit using an oxide a conductor, which was developed in order to eliminate the conventional drawbacks as described above. By irradiating the irradiated portion, the irradiated portion is decomposed or melted, the superconducting phase is destroyed, and the superconducting phase is transformed into a non-a conductive phase, and a circuit is formed with the portion that is not irradiated with the laser.

That is, in the method of the present invention, when a non-8 conductive phase of a predetermined shape is formed in a predetermined portion of an oxide a conductive molded body, CO2 is added to that portion.
By using a gas laser, YAG laser, etc., and adjusting the beam spot diameter and backlight of the laser beam, the part is thermally decomposed or melted to form a non-molecular shape in the desired shape.
'rrt, a conductive phase is formed and the superconducting current is interrupted.

Tree 5i! ! When light irradiates an oxide superconductor with radar to form a non-iB conductive phase, it does not completely cut the molded body, but only partially alters its quality.
The bonding strength of this part is not lost at all.

Figure 3 shows an example of a situation in which the tll'i'lt conductive phase changes in quality due to laser irradiation. The middle part of the figure is the molten part that has been melted and altered by the laser beam, and S is the molten part that has been heated by the laser beam. It is a solid part that shows decomposed and altered parts, and the superconducting phase in only a predetermined part is destroyed and a non-superconducting phase is formed without the laser beam completely penetrating it.

In this way, the Mi71 conductive molded body is not cut, but only the f-quality is made in that part, so the strength etc. of the oxide superconducting hollow body remains unchanged. Furthermore, there is no fear that the characteristics of the superconducting phase other than the laser beam irradiation portion will deteriorate.

For example, a material with a thickness of 3III and an inner diameter of Loom-
A cylindrical mold body with a length of 100 mm in φ is rotated at a predetermined speed and set to move upward or downward in the axial direction, and when it is irradiated with a fixed CO2 gas laser 30w with a spot diameter of 3IIIφ, the above-mentioned result is obtained. The spot irradiated part of the cylinder melts or decomposes and YB azCu3
0. - x superconducting phase is altered, Y, , BalCu, 0.
, BaCuO2, CuO, and other non-superconducting phases are formed.

In this way, a spiral non-superconducting phase with a predetermined pitch is formed in the cylindrical mold body, so that a superconducting coil is formed.

In the above case, a fixed type CO2 gas laser was used, so the irradiated r & mold body had to be moved northward while rotating at a predetermined speed, but if a scanning laser was used, the molded body could be fixed and moved. Of course, it is also possible to use a laser for scanning.

In addition, since the temperature at which the irradiated oxide superconductor melts or decomposes and changes its quality is different, refer to the phase diagram in advance to determine the beam spot diameter and power of the laser beam in the Canadian system.
By setting design conditions such as heat absorption, movement speed, cooling rate, etc., the desired non-superconducting phase can be formed.

Next, the method of the present invention will be explained using examples.

(D) Examples Example I Molded with YBa, Cu3o7-x oxide a-ri7 conductive material, height 4 mm, inner diameter 50 mmφ, length 100
Set the cylindrical mold body of 1I11 so that it moves slowly upward while rotating at a circumferential speed of 2 ays 1 minute, and use a fixed CO and gas laser 30w to align the dots at 2 ■ spots to measure the outer periphery of the cylindrical mold body. It was irradiated to form a spiral non-superconducting phase with a pitch of 4II11 while preventing the Lechie light from passing through the surface, and the superconducting phase in a predetermined portion was melted and decomposed to change its quality, and then it was rapidly cooled.

As a result, a non-superconducting phase was completely formed in the portion irradiated with the laser beam, and the desired molded body of the a-conducting coil could be produced.

The current f direct that could be passed through this coil was 400 A/cmz, which was equivalent to the current value that could be passed in bulk.

Comparative Example The same YB a2Cu30. as used in Example 1 was used.
-x Oxide a A ring-shaped molded body with a height of 4 mm, an inner diameter of 50 mm, a width of 5 mm, and a diameter of 5 mm is cut out to form a circle M, and the flow is stopped. A piece of oxide was prepared, and fixed by shifting the incision so that it would form a coil shape. Powder paste was applied, and the other parts (parts to be non-mW conductive) were coated with Batest, which is made of bismuth oxide powder, and heated at 920°C for 10
A coil was fabricated by heat treatment for a period of time and diffusion bonding.

As a result, current flows through the diffusion bonded coil, but the current ti value that can flow through the bond is 10A/ctm.
z is extremely small, so the current that can be passed as a coil is also small, and the current that can be passed only with this ring is 20A/am.
” has decreased significantly.

(E) Results of the invention) As described above, according to the method of the present invention, the beam spot diameter of the laser is adjusted and irradiated onto a predetermined portion of the oxide superconductor until the temperature reaches a temperature that changes the Mi conductive phase by melting or decomposition. By heating, the superconducting phase in the irradiated area is destroyed and transformed into a non-superconducting phase such as a semiconductor or an insulator, making it possible to easily create any circuit without deteriorating its characteristics.

Moreover, the present invention does not require any gas etching or wet etching as required in conventional methods, and can be processed easily, quickly and with high precision.Furthermore, the non-superconducting phase formed by laser irradiation acts as a structural material. There are also advantages.

In addition, although the above-mentioned example explained circuit production of Y-Ba-Cu-0 type oxide superconductor, it goes without saying that the method of the present invention can be applied to other oxide superconductors.

4. Brief description of the drawings Fig. 1 is a perspective view showing a coiled circuit produced from a cylindrical oxide superconducting molded body by the method of the present invention, and Fig. 2 is a plan view showing a circuit similarly produced from a flat plate-shaped molded body. 3 are cross-sectional explanatory diagrams showing an example of a situation where the KFI conductive phase melts or decomposes and changes in quality due to laser irradiation.

Symbol explanation 1-Cylindrical oxide superconducting molded body 2-Non-superconducting phase 3-Superconducting phase 4-Tabular oxide superconducting molded body 5-Go, gas laser 6-Laser beam pattern-Melted altered part S-
Thermal decomposition altered part patent Applicant Dowa Mining Co., Ltd. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A method for producing a circuit of an oxide superconductor, which comprises forming a circuit by irradiating the oxide superconductor with a laser to transform the irradiated portion into a non-superconducting phase.