Preparation of thin film superconducting oxides

Claim 3

The method of claim 1 wherein the film is free-standing.

Claim 4

The method of claim 1 wherein the film is supported on a flat compatible substrate.

Claim 5

The method of claim 1 wherein the film is supported on a ribbon, wire, coil or other three-dimensional compatible substrate.

Claim 6

The method of claim 1 wherein the film thickness is less than one micrometer.

Claim 7

The method of claim 1 wherein the cation constituents of the oxide film, the thickness of the film, and the firing conditions are selected so that the film is dense.

Claim 8

The method of claim 1 wherein the cation constituents of the oxide film, the thickness of the film, and the firing conditions are selected so that the film is porous.

Claim 9

The method of claim 1 where multiple coatings are used to form thicker or more dense solid superconducting film.

Claim 10

The method of claim 2 wherein a supporting framework supports the superconducting film.

Claim 11

The method of claim 9 wherein the supporting framework is a wire frame or mesh.

Claim 12

The method of claim 10 wherein the wire frame or mesh is dipped into the organic liquid solution to form the film.

Claim 13

The method of claim 2 wherein the liquid film is spread on a substrate, dried, and separated from the substrate.

Claim 14

The method of claim 3 or 4 wherein the substrate is a single crystalline material.

Claim 15

The method of claim 3 or 4 wherein the substrate is dipped into the organic liquid solution to form a liquid film.

Claim 16

The method of claim 3 wherein the organic liquid solution is applied to a spinning substrate.

Claim 17

The method of claim 3 or 4 wherein the substrate is wet or partially wet by the organic liquid solution.

Claim 18

The method of claim 3, 4, 13, 14, 15, or 16 wherein the substrate is chosen from the group consisting of SiO 2 , SiC, Si, SrTiO 3 , BaTiO 3 , MgO, carbon coated with SiC, Al 2 O 3 , stainless steel, copper alloys, nickel alloys, cobalt alloys, gold alloys, platinum alloys and tantalum alloys.

Claim 19

The method of claim 15 wherein the film is dried by spinning in air.

Claim 20

The method of claim 15 wherein the film is dried by heating the substrate and film while spinning.

Claim 21

The method of claim 15 wherein the film is dried by heating the substrate and film after spinning.

Claim 22

The method of claim 1 wherein the cations are chosen from the group consisting of La, Ba, Cu, Y, Sr, Ca, and rare-earth ions such as Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu.

Claim 23

The method of claim 1 wherein the oxide film comprises La 2-x M x CuO 4-y where M is an alkaline earth cation.

Claim 24

The method of claim 1 wherein the oxide film comprises NBa 2 Cu 3 O 7-x where N is Y, or a rare-earth ion such as La, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu.

Claim 25

The method of claim 1 wherein the organic liquid solution includes ethylene glycol as the polymerizing alcohol and critic acid as the chelating organic acid.

Claim 26

The method of claim 1 wherein the cation constituents are introduced as compounds chosen from the group consisting of La 2 O 3 , CuO, Y 2 O 3 , SrCO 3 , BaCO 3 , and Cu 2 O.

Claim 27

The method of claim 20 wherein the liquid film solution is dried at a temperature in the range of 100°-200° C.

Claim 28

The method of claim 1 wherein the solid organic polymer is fired in an oxidizing atmosphere.

Claim 29

A method of claim 1 wherein the cations comprise La, Sr, and Cu.

Claim 30

The method of claim 1 wherein the oxide film comprises La 1 .825 Sr 0 .175 CuO 4-x where x is less than 1.0.

Claim 31

The method of claim 1 wherein the cations comprise Y, Ba and Cu.

Claim 32

The method of claim 1 wherein the oxide film comprises YBa 2 Cu 3 O 7-x where x is less than 1.0.

Claim 33

The method of claim 1 wherein the organic acid is citric acid.

Claim 34

The method of claim 1 wherein the organic acid is lactic acid.

Claim 35

The method of claim 1 wherein the organic acid is glycolic acid.

Claim 36

The method of claim 1 wherein the alcohol is ethylene glycol.

Claim 37

The method of claim 1 wherein the alcohol is glycerol.

Claim 38

The method of claim 28 wherein the polymer is fired for approximately one-half hour at approximately 800° C. and then cooled to room temperature.

Claim 39

The method of claim 30 wherein the polymer is fired for approximately one-half hour at approximately 900° C. and then cooled to room temperature.

Claim 40

The method of claim 3 wherein the substrate is a single crystalline material for inducing a preferred crystalline orientation in the thin film.

Claim 41

Method of preparing a multiple layer copper oxide based superconducting oxide film comprising the steps of: making an organic liquid solution of the cation constituents of a first superconducting oxide film layer by chelating a precursor solution containing said cation constituents with an organic acid and adding a polymerizing alcohol; forming the solution into a liquid film; drying and heating the liquid film solution to obtain a solid organic polymer or resin; firing the polymer to obtain a first layer of the superconducting oxide; making an organic liquid solution of the cation constituents of a second superconducting oxide film layer by chelating a precursor solution containing the cation constituents of the second superconducting oxide film with an organic acid and adding a polymerizing alcohol; forming the solution into a liquid film on the first superconducting oxide layer; drying and heating the liquid film solution to obtain a second solid organic polymer or resin; firing the second polymer to obtain a second superconducting oxide layer; and repeating the process for additional superconducting oxide layers.

Claim 42

Method of preparing a multiple layer copper oxide based superconducting oxide film comprising the steps of: making an organic liquid solution of the cation constituents of a first superconducting oxide film layer by chelating a precursor solution containing said cation constituents with an organic acid and adding a polymerizing alcohol; forming the solution into a liquid film; drying and heating the liquid film solution to obtain a solid organic polymer or resin; firing the polymer to obtain a first layer of the superconducting oxide; making an organic liquid solution of the cation constituents of a second superconducting oxide film layer by chelating a precursor solution containing the cation constituents of the second superconducting oxide film with an organic acid and adding a polymerizing alcohol; forming the solution into a liquid film on the first superconducting oxide layer; drying and heating the liquid film solution to obtain a second solid organic polymer or resin; firing the second polymer to obtain a second superconducting oxide layer; and repeating the process for additional superconducting oxide layers.