The University of Chicago

Superconductive Components, Inc.

Suvankar Sengupta

Donglu Shi

Volker R Todt

Dean J Miller

Uthamalingam Balachandran

Michael T Lanagan

Kenneth C Goretta

John C Parker

Richard W Siegel

Jieguang Hu

Jai Subramanium

Joey Michael Corpus

A process which relies on a joining technique between two individual strongly linked superconductors is disclosed. Specifically, this invention relates to fabrication of single domains of YBa Cu O or YBa Cu O with the addition of Y BaCuO and/or other secondary phases such as Pt/PtO , CeO , SnO , Ag, Y O and other rare earth oxides, by using a top-seeded, melt processing technique. Beginning with a single crystal seed such as Nd Ba Cu O or SmBa Cu O crystals, a melt-textured YBCO domain with crystallographic orientation nearly similar to that of the seed crystal can be fabricated. The samples are next machined to desired geometrical shapes. A bonding material is then applied to the ac plane. Low solidification or recrystalization point, similar crystal structure to that of YBa Cu O , and capability of growing epitaxially on YBCO domains are critical parameters of the bonding material. The pre-bonded samples are then heat treated such that the bonding material grows epitaxially on the ac plane of YBCO domains resulting in a strongly linked joint. A small amount of pressure may be used to keep neighboring domains together.

Large strongly linked superconducting monoliths and process for making the same

A process which relies on a joining technique between two individual strongly linked superconductors is disclosed. Specifically, this invention relates to fabrication of single domains of YBa,Cu,O,or YBa,Cu,O,with the addition of Y,BaCuO,and/or other secondary phases such as Pt/PtO,, CeO,, SnO,, Ag, Y,O,and other rare earth oxides, by using a top-seeded, melt processing technique. Beginning with a single crystal seed such as Nd,Ba,Cu,O,or SmBa,Cu,O,crystals, a melt-textured YBCO domain with crystallographic orientation nearly similar to that of the seed crystal can be fabricated. The samples are next machined to desired geometrical shapes. A bonding material is then applied to the ac plane. Low solidification or recrystalization point, similar crystal structure to that of YBa,Cu,O,, and capability of growing epitaxially on YBCO domains are critical parameters of the bonding material. The pre-bonded samples are then heat treated such that the bonding material grows epitaxially on the ac plane of YBCO domains resulting in a strongly linked joint. A small amount of pressure may be used to keep neighboring domains together.

Large, strongly linked superconducting monoliths and process for making the same

A method of preparing a high temperature superconductor. A method of preparing a superconductor includes providing a powdered high temperature superconductor and a nanophase material. These components are combined to form a solid compacted mass with the material disposed in the polycrystalline high temperature superconductor. This combined mixture is rapidly heated, forming a dispersion of nanophase size particles without a eutectic reaction. These nanophase particles can have a flat plate or columnar type morphology.

Engineered flux-pinning centers in BSCCO TBCCO and YBCO superconductors

In accordance with the invention a process is provided for achieving a phase-pure BSCCO or lead doped BSCCO powder or precursor of the 2201, 2212 or 2223 phase. In this process a cation solution is intimately mixed with an anion solution and precipitation is caused at a carefully controlled pH in the range from about 10 to about 12.5. The resulting product is filtered and dried or heat-treated at a temperature of from about 400.degree. to about 500.degree. C. for a period of from about 8 to about 12 hours. The heat-treated powder is then subjected to a second heat treatment at a reduced oxygen of from about 3 to about 10 torr and a temperature of from about 700.degree. to about 800.degree. to form a precursor powder. The precursor powder is heat-treated at ambient pressure in CO.sub.2 -free air from about 12 to about 31 hours or more at a temperature of from about 800.degree. to about 850.degree. C. A product results having a particle size of less than 5 microns, low carbon content and a phase purity of at least about 95 percent.

Fine-particle bi-sr-ca-cu-o having high phase purity made by chemical

A method of fabricating bulk YBa.sub.2 Cu.sub.3 O.sub.x where compressed powder oxides and/or carbonates of Y and Ba and Cu present in mole ratios to form YBa.sub.2 Cu.sub.3 O.sub.x are heated in the presence of a Nd.sub.1+x Ba.sub.2-x Cu.sub.3 O.sub.y seed crystal to a temperature sufficient to form a liquid phase in the YBa.sub.2 Cu.sub.3 O.sub.x while maintaining the seed crystal solid. The materials are slowly cooled to provide a YBa.sub.2 Cu.sub.3 O.sub.x material having a predetermined number of domains between 1 and 5. Crack-free single domain materials can be formed using either plate shaped seed crystals or cube shaped seed crystals with a pedestal of preferential orientation material.

Large single domain 123 material produced by seeding with single crystal

A method of preparing single crystals. The method of preparation involves preparing precursor materials of a particular composition, heating the precursor material to achieve a peritectic mixture of peritectic liquid and crystals, cooling the peritectic mixture to quench directly the mixture on a porous, wettable inert substrate to wick off the peritectic liquid, leaving single crystals on the porous substrate. Alternatively, the peritectic mixture can be cooled to a solid mass and reheated on a porous, inert substrate to melt the matrix of peritectic fluid while leaving the crystals unmelted, allowing the wicking away of the peritectic liquid.

Method for harvesting single crystals from a peritectic melt

A method of preparing high temperature superconductor single crystals. The method of preparation involves preparing precursor materials of a particular composition, heating the precursor material to achieve a peritectic mixture of peritectic liquid and crystals of the high temperature superconductor, cooling the peritectic mixture to quench directly the mixture on a porous, wettable inert substrate to wick off the peritectic liquid, leaving single crystals of the high temperature superconductor on the porous substrate. Alternatively, the peritectic mixture can be cooled to a solid mass and reheated on a porous, inert substrate to melt the matrix of peritectic fluid while leaving the crystals melted, allowing the wicking away of the peritectic liquid.

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Upper Arlington, OH, United States of America

Suvankar Sengupta