JPH01111702A - Production of room temperature superconductor from composite oxide utilizing irradiation - Google Patents

Abstract

PURPOSE:To obtain the above superconductor exhibiting superconducting phenomenon stably at the b. p. of liquid N2 - <= room temp. by irradiating a Y, Sc, or Ln type compound oxide having perovskite structure with radiant rays. CONSTITUTION:A powder mixture having <=1mu particle size is produced by mixing (i) Y2O3, or Sc2O3, or Ln2O3, with (ii) BaCO3 corresponding to an amt. of the element in a proportion of 2:1 to the amt. of the element of Y, or Sc, or Ln in (i), and (iii) CuO corresponding to an amt. of the element in a proportion of 3:1 to the amt. of the element Y, Sc, or Ln in (i), and pulverizing the mixture. The powder mixture is then precalcined in the air at 1,100-1,200 deg.K for about 10hr, and pulverized, and calcined in the air at 1,200-1,400 deg.K for about 25hr in the form of powder, if necessary, in the form of solid produced by pressing, thin film, or packed form in a hollow tube. Thus, a Y, Sc, or Ln type compound oxide having perovskite structure is obtd. The compound oxide is irradiated with electron beams contg. 10<10>-10<21>/cm<3> particles capable of causing atomic displacement, or radiant rays such as proton beams or heavy ion beams contg. 10<15>-10<18> charged particles or neutron beams, etc., contg. same amt. of uncharged particles, in gaseous He atmosphere at room temp. - 600 deg.K.

Description

[Detailed description of the invention] (a) Industrial application field This invention can be applied to a wide range of fields as follows. (1)
) Use in superconductors for power storage in space or underground space; ■ Use in superconductors for power generation, transmission, or distribution with little electrical energy loss; irradiation with radiation to form superconducting circuits and Josephson junction elements; (4) use in other devices that apply superconductivity;

(Roff) Conventional technology In conventional electrical equipment and electronic devices, there is always a huge loss due to heat generation of electrical energy and llI harm due to heat generation, and it is extremely difficult to overcome this I+Tl!fl. The traditional method of manufacturing superconductors, which involves simply sintering, is difficult to manufacture, even for recently developed oxide high-temperature superconductors.
Since its critical temperature is below about 90° in absolute terms, there are still problems in putting superconductors into practical use.

(c) Problems to be solved by the invention The purpose of this invention is to use radiation irradiation to produce a superconductor that stably exhibits superconductivity in a temperature range from liquid nitrogen temperature to room temperature. .

(d) Means for Solving the Problem With conventional materials and techniques, it has been impossible to produce a wJ using a sintering method that can stably form the superconducting ring 1 at an absolute temperature of about 100° or more. Below is a superconductor that is stable at high temperatures according to this invention! I will explain how to create +2.

1) Synthesis method of precursor ■ Yttrium-based (Y-
Ba-Cu-0 system), scandium system (Sc-Ba-C
In order for the composite oxides of u-0 series) and lanthanide series (Ln-Ba-Cu-0 series) to constitute a perovskite structure after firing, ittria (Y to s), scandia (SC201), or Lanthanide oxide (
L n 20 i> respectively, barium carbonate (BaCO
, ) and oxidized secondary tjA (CuO) powder. To this end, if the elemental amount of yttrium, scandium, or lanthanide, which has similar ionic radius and chemical properties, is 1, then the elemental amount ratio of barium is 2. WA3
and baked as described below.

■ The blended powder is mixed and pulverized using an ordinary mixer and pulverizer to form a homogeneous mixed powder with a particle size of approximately 1 micron or less. This mixed powder is calcined in the atmosphere at about 1100-1200' for about 10 hours. This calcined powder is reused with a particle size of approximately 1
The means for forming a zero-order high temperature superconductor by pulverizing it to micron size or less to make a calcined powder depends on the form of the superconductor, but it depends on the form of the superconductor: (1) powder, ■ solid body by pressing, (3)
The thin film on the substrate, (4) is filled into a hollow tube, etc., and then subjected to main firing. The firing conditions depend on the shape and dimensions of the superconductor, but are, for example, about 25 hours in air at 1200-1400''K.

2) Radiation treatment method In order to generate the structure necessary for the above-mentioned fired body to exhibit superconducting properties, that is, a superconducting phase, the fired body is treated in a helium gas atmosphere at a temperature range from room temperature to approximately 600°. and irradiate the fired body with radiation. The appropriate radiation dose is 10'6 to 10'' particles/cm of charged particle beam.
”, and with uncharged particle beam 1019~l Q IS pieces/
cm'' range. If the irradiation dose exceeds these upper limits, the superconducting phase will be destroyed.

(e) Attach an electrical resistance measurement lead to the action precursor, and measure the electrical resistance value of the irradiated surface and after irradiation by 20° from room temperature in the radiation irradiation equipment.
Figures 1 and 2 were obtained by making continuous measurements over a long period of time during the cooling process to K and examining the temperature dependence of the electrical resistance during each process. In both Figures 1 and 2, the horizontal axis represents absolute temperature, and the vertical axis represents electrical resistance ¥1 (Ω).
As an example of this invention, temperature changes in the electrical resistance of the material before and after irradiation of a lanthanum-barium-copper-oxygen complex oxide with a helobskite structure with nuclear reactor radiation (neutron beam, etc.) are shown. It is something. FIG. 1 is the result of a relatively low dose of radiation, and FIG. 2 is the result of a higher dose of radiation than FIG.

In both figures, the electrical resistance value of the material changes as shown by the arrow during the cooling process, and the superconductivity of the material clearly appears stably in the temperature range from liquid nitrogen temperature to room temperature due to radiation irradiation. I understand. Table 1 and Table 2 show the conditions for irradiation of the precursor materials in FIGS. 1 and 2, respectively.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the electrical resistance and temperature of the precursor material before irradiation (a) and the relationship between the electrical resistance and temperature of the same material after irradiation (b and C) when the radiation dose is relatively low. Figure 2 shows the relationship between the electrical resistance and temperature of the precursor material before irradiation (a') and the relation between the electrical resistance and temperature of the precursor material after irradiation (a') when the radiation dose is relatively high. b' and c') are shown. Procedural correction tooth (method) February 12, 1988

Claims (1)

[Claims] 1 Yttrium-based scandium-based and lanthanide-based composite oxides with a perovskite structure are irradiated with radiation, that is, charged particles such as electron beams, proton beams, and heavy ion beams that can cause atomic displacement, or uncharged particles such as neutron beams. A method for manufacturing superconductors that stably exhibit superconductivity in the temperature range from temperature to room temperature.