Process for producing superconducting material

Claim 2

A process for producing a film of oxide superconducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i MO.sub.y ( 1) or (L.sub.x A.sub.1-x).sub.i M.sub.i-z Cu.sub.z O.sub.y ( 2) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; i is 1, 3/2 or 2; y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2; and z is 0<z<1, which comprises depositing, on a metal film of one element selected from the group consisting of the elements L, A, and M, an oxide of the rest of the elements other than that of the metal film, and heat treating the metal film and the resulting deposited layer to carry out a diffusion reaction therebetween.

Claim 3

A process according to claim 1, wherein a concentration gradient of the constituting metal elements is formed by the diffusion reaction in the film in the thickness direction.

Claim 4

A process for producing a film of oxide superconducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i MO.sub.y ( 1) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; i is 1, 3/2 or 2; and y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2, which comprises using as a target an oxide represented by the formula: (L.sub.x A.sub.1-x).sub.i CuO.sub.y ( 4) wherein L, A, x, i and y are as defined above, and as a substrate a film of the element M, passing an alternating electric current through the substrate so as to maintain the temperature of the substrate at 1000° to 1400° C., conducting sputtering by using a direct current magnetron sputtering apparatus in an argon atmosphere with a pressure of 0.1 to 0.8 Torr at a sputtering voltage of 200 to 400V and a sputtering electric current of 20 mA to 100 mA, and conducting a diffusion reaction between the substrate and the sputtered layer.

Claim 5

A process for producing a film of oxide superconducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i MO.sub.y ( 1) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; i is 1, 3/2 or 2; and y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2, which comprises using as a target an oxide represented by the formula: (L.sub.x A.sub.1-x).sub.i CuO.sub.y ( 4) wherein L, A, x, i and y are as defined above, and as a substrate a film of the element M, passing an alternating electric current through the substrate so as to maintain the temperature of the substrate at 1000° to 1400° C., conducting sputtering by using a direct current magnetron sputtering apparatus in an argon atmosphere with a pressure of 0.1 to 0.8 Torr at a sputtering voltage of 200 to 400V and a sputtering electric current of 20 mA to 100 mA, and conducting a diffusion reaction between the substrate and the sputtered layer.

Claim 6

A process according to claim 3, which further comprises subjecting the resulting film-coated substrate to heat treatment at 500° to 600° C. for 10 to 30 minutes in a weakly oxidizing atmosphere.

Claim 7

A process for producing a powder of oxide superconducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i MO.sub.y ( 1) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; i is 1, 3/2 or 2; and y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2, which comprises depositing a film of pure metal of the element M on the outer surface of an oxide represented by the formula: (L.sub.x A.sub.1-x).sub.i CuO.sub.y ( 4) wherein L, A, x, i and y are as defined above, in vacuum, substituting the Cu of the oxide of the formula (4) with the element M at 600° to 900° C. by the diffusion of the element M, subjecting the resulting product to annealing in an oxidizing atmosphere, and pulverizing the resulting annealed product.

Claim 8

A process for producing a powder of oxide superconducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i MO.sub.y ( 1) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; i is 1, 3/2 or 2; and y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2, which comprises depositing a film of pure metal of the element M on the outer surface of an oxide represented by the formula: (L.sub.x A.sub.1-x).sub.i CuO.sub.y ( 4) wherein L, A, x, i and y are as defined above, in vacuum, substituting the Cu of the oxide of the formula (4) with the element M at 600° to 900° C. by the diffusion of the element M, subjecting the resulting product to annealing in an oxidizing atmosphere, and pulverizing the resulting annealed product.

Claim 9

A process for producing a film of superconducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i MO.sub.y ( 1) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; i is 1, 3/2 or 2; and y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2, which comprises using as a substrate at least one material selected from the group consisting of silicon, aluminum oxide, silicon oxide, magnesium oxide and zirconium oxide, forming a metal thin film of the element M on the substrate, depositing a film of L x A 1-x , wherein L, A and x are as defined above, on the metal thin film, and subjecting the resulting film to heat treatment to carry out a diffusion reaction of these elements.

Claim 10

A process for producing a film of superconducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i MO.sub.y ( 1) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; i is 1, 3/2 or 2; and y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2, which comprises using as a substrate at least one material selected from the group consisting of silicon, aluminum oxide, silicon oxide, magnesium oxide and zirconium oxide, forming a metal thin film of the element M on the substrate, depositing a film of L x A 1-x , wherein L, A and x are as defined above, on the metal thin film, and subjecting the resulting film to heat treatment to carry out a diffusion reaction of these elements.

Claim 11

A process according to claim 6, wherein a plurality of the metal thin films of the element M and a plurality of the L x A 1-x films are laminated alternately on the substrate before the heat treatment.

Claim 12

A process for producing a superconducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i MO.sub.y ( 1) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; i is 1, 3/2 or 2; and y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2, which comprises depositing a film of L x A 1-x , wherein L, A and x are as defined above, on a metal tape or a substrate of the element M, and subjecting the resulting film to heat treatment to carry out a diffusion reaction of these elements.

Claim 13

A process for producing a superconducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i MO.sub.y ( 1) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; i is 1, 3/2 or 2; and y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2, which comprises depositing a film of L x A 1-x , wherein L, A and x are as defined above, on a metal tape or a substrate of the element M, and subjecting the resulting film to heat treatment to carry out a diffusion reaction of these elements.

Claim 14

A process according to claim 8, wherein the deposition of L x A 1-x film is carried out by a sputtering method or a molecular beam epitaxy method.

Claim 15

A process for producing a film of super-conducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i M.sub.1-z Cu.sub.z O.sub.y ( 2) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; z is 0<z<1; i is 1, 3/2 or 2; y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2, which comprises using a substrate made of at least one member selected from the group consisting of silicon, aluminum oxide, silicon oxide, magnesium oxide, and zirconium oxide, forming a metal thin film of the element M on the substrate, depositing an amorphous or polycrystalline film of (L x A 1-x ) i CuO y on the metal thin film, and subjecting the resulting film to heat treatment to diffuse the element M into the (L x A 1-x ) 1 CuO y film.

Claim 16

A process for producing a film of super-conducting material represented by the formula: (L.sub.x A.sub.1-x).sub.i M.sub.1-z Cu.sub.z O.sub.y ( 2) wherein L is at least one element selected from the group consisting of Sc, Y, lanthanide elements of atomic numbers 57 to 71, and Li, Na, K, Rb, Cs and Fr belonging to the group Ia of the periodic table; A is at least one element selected from alkaline earth metal elements; M is at least one element selected from the group consisting of V, Nb, Ta, Ti, Zr and Hf; x is 0<x<1; z is 0<z<1; i is 1, 3/2 or 2; y is 0<y≦3 in the case of i=1, or 0<y≦4 in the case of i=3/2 or 2, which comprises using a substrate made of at least one member selected from the group consisting of silicon, aluminum oxide, silicon oxide, magnesium oxide, and zirconium oxide, forming a metal thin film of the element M on the substrate, depositing an amorphous or polycrystalline film of (L x A 1-x ) i CuO y on the metal thin film, and subjecting the resulting film to heat treatment to diffuse the element M into the (L x A 1-x ) 1 CuO y film.

Claim 17

A process for producing a film of La--Sr--Nb--O oxide super conducting material which comprises using as a target a La--Sr--cu--O 4 sintered body, and as a substrate a niobium material, passing an alternating electric current through the substrate so as to maintain the temperature of the substrate at 1000° to 1400° C., conducting sputtering in an argon atmosphere with a pressure of 0.1 to 0.8 Torr at a sputtering voltage of 200 to 400V and a sputtering electric current of 20 mA to 100 mA to form a film of La--Sr--Cu--O 4 on the niobium substrate surface, conducting a diffusion reaction between the substrate and the sputtered layer, and subjecting the resulting niobium substrate to heat treatment at 500°-600° C. for 10-30 minutes in a weakly oxidizing atmosphere.

Claim 18

A process for producing a film of La--Sr--Nb--O oxide super conducting material which comprises using as a target a La--Sr--cu--O 4 sintered body, and as a substrate a niobium material, passing an alternating electric current through the substrate so as to maintain the temperature of the substrate at 1000° to 1400° C., conducting sputtering in an argon atmosphere with a pressure of 0.1 to 0.8 Torr at a sputtering voltage of 200 to 400V and a sputtering electric current of 20 mA to 100 mA to form a film of La--Sr--Cu--O 4 on the niobium substrate surface, conducting a diffusion reaction between the substrate and the sputtered layer, and subjecting the resulting niobium substrate to heat treatment at 500°-600° C. for 10-30 minutes in a weakly oxidizing atmosphere.