# US 5,348,935 A · Highly oxidized superconductors

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- Number: US 5,348,935 A
- Document ID: US5348935A
- Status: Granted
- Kind: A
- Application number: 07/890,346
- Filed: 1992-05-22
- Granted: 1994-09-20
- Earliest claimed: 1988-10-28
- Assignees: The Regents of the University of California
- Inventors: Donald E. Morris
- Web page: https://patentgrep.com/patent/US5348935A

## CPC

- C04B 35/64: Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F})
- C04B 35/45: based on copper oxide or solid solutions thereof with other oxides
- H10N 60/0661: {Processes performed after copper oxide formation, e.g. patterning}
- H10N 60/0828: {Introducing flux pinning centres}
- Y10S 505/742: Annealing
- Y10S 505/78: Yttrium and barium-, e.g. YBa2Cu307
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Novel superconducting materials in the form of compounds, structures or phases are formed by performing otherwise known syntheses in a highly oxidizing atmosphere rather than that created by molecular oxygen at atmospheric pressure or below. This leads to the successful synthesis of novel superconducting compounds which are thermodynamically stable at the conditions under which they are formed.

## Claims

### Claim 1

A method for producing an oxide, high temperature superconductor material by a solid state method under production conditions comprising reacting a plurality of starting materials in an oxygen partial pressure exceeding 2 atm., said starting materials consisting essentially of a mixture of compounds which are themselves not high-temperature superconductors which combine to form said high temperature superconductor at said production conditions.

### Claim 2 (depends on 1)

A method of claim 1, wherein said starting materials comprise a rare earth element containing compound and at least one group II element selected from the group consisting of Cd, Mg, Ca, Sr, and Ba, said starting materials having a stoichiometry of rare earth elements to the sum of said at least one group II elements which is different from said superconducting material.

### Claim 3 (depends on 1)

A method of claim 1, wherein said starting materials comprise an oxide of a rare earth element.

### Claim 4 (depends on 1)

A method of claim 1, wherein said starting materials comprise an oxide of a metallic element.

### Claim 5 (depends on 1)

A method of claim 1, wherein said starting materials are combined in relative amounts such that the stoichiometric ratio of metallic elements is approximately the same as that of said superconductor material.

### Claim 6 (depends on 1)

A method of claim 1, wherein said starting materials comprise a powdered material.

### Claim 7 (depends on 1)

A method of claim 1, wherein said starting materials do not include any high temperature superconductor compounds.

### Claim 8 (depends on 1)

A method of claim 1, wherein said superconductor material is selected from the group consisting of:
(a) 1-2-3 compounds;
(b) 2-4-7 compounds; and
(c) 1-2-4 compounds.

### Claim 9 (depends on 1)

A method of claim 1, wherein said oxygen partial pressure is greater than about three atmospheres.

### Claim 10 (depends on 1)

A method of claim 1, wherein said solid state method reaches a temperature of at least about 500.degree. C.

### Claim 11 (depends on 1)

A method of claim 1, wherein said superconductor material is substantially pure.

### Claim 12 (depends on 1)

A method of claim 1, wherein said superconductor material is in polycrystalline bulk ceramic form.

### Claim 13 (depends on 1)

The method as recited in claim 1 wherein said pressure exceeds 3 atmospheres.

### Claim 14 (depends on 1)

The method as recited in claim 1 wherein said pressure exceeds 10 atmospheres.

### Claim 15 (depends on 1)

The method as recited in claim 1 wherein said pressure exceeds 60 atmospheres.

### Claim 16 (depends on 1)

A method of claim 1 further comprising the step of sintering said high temperature superconductor in oxygen at about the same temperature, pressure and time schedule used in the reaction.