Bismuth(bi)-(e.g., Bicasrcu0) Patents (Class 505/782)
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Patent number: 5508252Abstract: A substance which has a Cu--O plane containing crystal structure in its unit cell and which is called a Bi oxide superconductor consisting essentially of Bi, Sr, Ca, Cu, and O. Not only part of Bi but also part of Sr and/or Ca of the Bi oxide superconductor is substituted for Pb and rare earth elements (RE), respectively. The Pb substitution relaxes the structural modulation which is closely related to superconductivity of the Bi oxide superconductor and the RE substitution controls its carrier concentration. Accordingly, superconducting properties such as transition temperature and critical current density can be improved remarkably. In addition, not only oxide superconductors with excellent superconductivity can be prepared in a low oxygen content but also the surface condition of the prepared superconductors is stable.Type: GrantFiled: June 14, 1994Date of Patent: April 16, 1996Assignee: Kabushiki Kaisha ToshibaInventors: Noburu Fukushima, Hiromi Niu, Ken Ando
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Patent number: 5508256Abstract: A method of producing a high-temperature oxide superconducting material, which comprises the steps of (a) preparing a material corresponding to an oxide superconductor of the perovskite type structure consisting essentially of a first member selected from the group consisting yttrium, lanthanoids, thallium and bismuth; at least one alkaline earth metal; copper; and oxygen and (b) heating the material in the presence of an alkali metal selected from the group consisting of potassium, sodium, rubidium and cesium to a temperature around the melting point of the alkali metal or to a higher temperature for a time sufficient to effect grain growth in the superconductor material, thereby to produce the superconductor containing the alkali metal in an amount not larger than 4 mole % based on the first member.Type: GrantFiled: June 23, 1994Date of Patent: April 16, 1996Assignee: Hitachi, Ltd.Inventors: Teruo Kumagai, Tsuneyuki Kanai, Atsuko Soeta, Takaaki Suzuki, Kazutoshi Higashiyama, Tomoichi Kamo, Shinpei Matsuda, Kunihiro Maeda, Akira Okayama, Hideyo Kodama, Akira Yoshinari, Yoshimi Yanai
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Patent number: 5506196Abstract: A super conducting material is disclosed which exhibits super conducting properties at higher temperatures than known so far. The super conducting by the invented materials is exhibited at temperatures of over 110.degree. K. Various combinations of the components exhibits superconductivities even at temperatures of around 273.degree. K. or even around 300.degree. K. Contrary to known art superconducting materials, which require super cooled conditions and are suited only to sophisticated applications, and thereby have limited applications, the materials of this inventions do not always require super cooled conditions are suited for limitless applications and can work even at room temperature conditions. While a large range of choice of materials are suggested a few important combinations are made of oxides of Bismuth, Barium and Copper. Replacement of Barium by Thallium gives additional advantages.Type: GrantFiled: August 16, 1993Date of Patent: April 9, 1996Assignee: Magnetic Power, Inc.Inventor: Mihir Sen
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Patent number: 5502029Abstract: Superconductors using oxide superconducting materials having pinning centers inside crystal grains are enhanced in transmissible critical current density and allowed to have a high critical current density even in the magnetic field. A superconductor is produced comprising superconducting materials having a high irreversible magnetic field where the c axes of their crystals are oriented in one direction. This can be practically realized by heat-treating a superconducting material having the composition (Tl.sub.1-X1-X2 Pb.sub.X1 Bi.sub.X2)(Sr.sub.1-X3 Ba.sub.X3).sub.2 Ca.sub.2 Cu.sub.3 O.sub.9+X4 together with Bi.sub.2 Sr.sub.2 CaCu.sub.2 O.sub.8 having a tendency of growing in the form of plate crystal. Various apparatuses capable of working under cooling with liquid nitrogen let alone with liquid helium and having a high superconducting critical current density even in a high magnetic field can be produced.Type: GrantFiled: January 26, 1994Date of Patent: March 26, 1996Assignee: Hitachi, Ltd.Inventors: Toshiya Doi, Atsuko Soeta, Seizi Takeuchi, Tomoichi Kamo, Shinpei Matsuda
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Patent number: 5486501Abstract: BaCuO.sub.2.5 containing precursors for superconducting materials and process for making shaped superconductor articles therefrom.Type: GrantFiled: February 9, 1994Date of Patent: January 23, 1996Inventor: Shome N. Sinha
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Patent number: 5484766Abstract: A method for synthesizing ultrahomogeneous nanoparticles of precursor powder by coprecipitation in a water and oil microemulsion is disclosed. The powder is compressed and sintered to prepare an essentially pure 2223 superconductor.Type: GrantFiled: February 14, 1994Date of Patent: January 16, 1996Assignee: Electric Power Research Institute, Inc.Inventors: Dinesh O. Shah, Promod Kumar, Vinod K. Pillai
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Patent number: 5445766Abstract: The disclosed substance has a composition of a general chemical formula ofBi.sub.2 -(Sr.sub.2 Ca.sub.1).sub.1-x (La.sub.2 Y.sub.1).sub.x -Cu.sub.y -O.sub.z,where 0.4.ltoreq.x.ltoreq.1, y=2 and z=9-10.5, wherein said substance is an insulator or a semiconductor in the dark, and has a photoconductivity Q(.lambda.,T) in conjugate with superconductivity of a superconductor of an adjacent component of the Bi-SrCa-LaY-Cu-O system at and below a critical temperature (T) of less than 105-115K and below 65-85K at photoexcitation in an optical wavelength range (.lambda.) of 420-670 nm. The present invention relates to a method for producing the same and a superconductive optoelectronic device by using the same. The present invention also relates to an organized integration of the element or device into an apparatus to further develop a new field of "Superconductive Optoelectronics.Type: GrantFiled: July 15, 1992Date of Patent: August 29, 1995Assignee: The University of TokyoInventor: Taizo Masumi
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Patent number: 5430008Abstract: Superconducting materials and methods of forming superconducting materials are disclosed. Highly oxidized superconductors are heated at a relatively high temperature so as to release oxygen, which migrates out of the material, and form a non-superconducting phase which does not diffuse out of grains of the material. The material is then reoxidized at a lower temperature, leaving the non-superconducting inclusions inside a superconducting phase. The non-superconducting inclusions act as pinning centers in the superconductor, increasing the critical current thereof.Type: GrantFiled: October 28, 1991Date of Patent: July 4, 1995Assignee: The Regents of the University of CaliforniaInventor: Donald E. Morris
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Patent number: 5418512Abstract: This invention provides a superconducting magnetic shield and a magnetic shielding apparatus including the same, thereby accurately measuring an extremely weak magnetic field such an magnetoencephalographic waves by reducing the influence of magnetic field of the earth or magnetic noises.Type: GrantFiled: December 9, 1992Date of Patent: May 23, 1995Assignees: Mitsui Kinzoku Kogyo Kabushiki Shisha, Rikagaku KenkyushoInventors: Hiroshi Ohta, Masakazu Aono, Kazuhiko Kato, Kazutomo Hoshino, Hidefusa Takahara, Tomonobu Nakayama, Eiichi Sudoh
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Patent number: 5413981Abstract: A method for manufacturing the oxide superconductor according to the present invention comprises the steps of: mixing a starting material including Bi, Sr, Ca and Cu such that a mole ratio of Bi, Sr, Ca and Cu is 2:2+a:1+b:2+c, wherein a.gtoreq.0, b.gtoreq.0, c.gtoreq.0, and 0<a+b+c<3; melting the mixed material at a temperature of 900.degree. C.-1500.degree. C.; quenching rapidly the molten material; and annealing the quenched material at a partial molten temperature of 800.degree. C.-1000.degree. C. This method gives product wherein a precipitate of at least one compound in the group SrO, CuO and (Ca.sub.1-x Sr.sub.x).sub.2 CuO.sub.3 (wherein 0.gtoreq.x<1) is finely dispersed in the superconducting crystal of Bi.sub.2 Sr.sub.2 Ca.sub.1 Cu.sub.2 O.sub.y (wherein y is about 8). The precipitates act as flux pinning centers.Type: GrantFiled: July 19, 1993Date of Patent: May 9, 1995Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Kunihiko Egawa, Toshio Umemura, Shinichi Kinouchi, Mitsunobu Wakata, Shin Utsunomiya, Ayumi Nozaki
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Patent number: 5409888Abstract: To produce a high-temperature superconductor of the composition Bi.sub.2 (Sr,Ca).sub.3 Cu.sub.2 O.sub.8+x having a strontium to calcium ratio of 5:1 to 2:1 and a value of x between 0 and 2, the oxides and/or carbonates of bismuth, strontium, calcium and copper are vigorously mixed in a stoichiometric ratio. The mixture is heated at a temperature of 870.degree. to 1100.degree. C. until a homogeneous melt is obtained. The melt is poured into mold and allowed to solidify in them. The cast bodies removed from the molds are annealed for 6 to 30 hours at 780.degree. to 850.degree. C. Finally, the annealed cast bodies are treated for at least 6 hours at temperatures of 600.degree. to 820.degree. C. in an oxygen atmosphere. The cast bodies can be converted into shaped bodies of the desired sizes by mechanical processes before they are annealed. The shape and size of the shaped bodies may also be determined by the shape and dimensioning of the mold used in producing the cast bodies.Type: GrantFiled: January 11, 1994Date of Patent: April 25, 1995Assignee: Hoechst AktiengesellschaftInventors: Joachim Bock, Eberhard Preisler
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Patent number: 5401712Abstract: A ceramic superconductor is produced by close control of oxygen partial pressure during sintering of the material. The resulting microstructure of YBa.sub.2 Cu.sub.3 O.sub.x indicates that sintering kinetics are enhanced at reduced p(O.sub.2) and that because of second phase precipitates, grain growth is prevented. The density of specimens sintered at 910.degree. C. increased from 79 to 94% theoretical when p(O.sub.2) was decreased from 0.1 to 0.0001 MPa. The increase in density with decrease in p(O.sub.2) derives from enhanced sintering kinetics, due to increased defect concentration and decreased activation energy of the rate-controlling species undergoing diffusion. Sintering at 910.degree. C resulted in a fine-grain microstructure, with an average grain size of about 4 .mu.m. Post sintering annealing in a region of stability for the desired phase converts the second phases and limits grain growth.Type: GrantFiled: September 18, 1992Date of Patent: March 28, 1995Assignee: University of ChicagoInventors: Jitrenda P. Singh, Roger B. Poeppel, Kenneth C. Goretta, Nan Chen
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Patent number: 5401717Abstract: This invention is related to the preparation of an elongate conductor having a silver sheath, and a core of an aligned polycrystalline oxide superconductor having the approximate formula Bi.sub.2-x Pb.sub.x Sr.sub.2-a L.sub.a+b Ca.sub.1-b Cu.sub.2 O.sub.y where y is from 7.5 to 8.5, and L is a lanthanide. A powder mixture is formed comprised of a first portion of a superconducting bismuth oxide compound that can be reaction-sintered to form the core oxide superconductor, and a second portion of oxides suitable for reacting with the first portion to form the core oxide superconductor. An elongate body is formed having a silver sheath, and a core of the mixture. The body is deformed to align the first portion, and heated to reaction-sinter the first and second portions to form the core oxide superconductor.Type: GrantFiled: February 14, 1994Date of Patent: March 28, 1995Assignee: General Electric CompanyInventor: Kenneth W. Lay
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Patent number: 5401713Abstract: A new superconducting material composed mainly of compound oxide represented by the general formula:Tl.sub.h Ca.sub.j .alpha..sub.k(1-y) .beta..sub.ky Cu.sub.m O.sub.nwherein".alpha." represents Ba or Sr;".beta." represents any one of elements selected from a group comprising Na, K, Rb and Cs;"h", "j", "k", "m" and "n" are the atomic ratios each satisfies the following range:1.ltoreq.h.ltoreq.3, 1.ltoreq.j.ltoreq.3, 1.ltoreq.k.ltoreq.3,2.ltoreq.m.ltoreq.4 and 5.ltoreq.n.ltoreq.15 and"y" is a number which satisfies a range of 0.05.ltoreq.y.ltoreq.0.8.Type: GrantFiled: September 18, 1992Date of Patent: March 28, 1995Assignee: Sumitomo Electric Industries, Ltd.Inventor: Yasuko Torii
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Patent number: 5389603Abstract: A new class of high temperature superconductive oxides is disclosed. An exemplary member of the class has nominal composition Pb.sub.2 Sr.sub.2 Y.sub.0.5 Ca.sub.0.5 Cu.sub.3 O.sub.8 and has a transition temperature T.sub.c (onset) of about 79K.Type: GrantFiled: February 9, 1990Date of Patent: February 14, 1995Assignee: AT&T Corp.Inventors: Bertram J. Batlogg, Robert J. Cava
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Patent number: 5385882Abstract: There is disclosed a process for preparing a thallium-containing superconductive composition. In the first step of the process, a mixture of an inorganic salt (such as potassium chloride) and a powder compositon is provided; the powder composition contains at least three separate compounds which, in combination, correspond to the stoichiometry of the super-conductor to be produced. This mixture is then charged to a closed container, raised to a temperature of from 800-959 degrees Centigrade, and heated for from about 1 to about 12 hours; thereafter, it is cooled to a temperature of 600 degrees Centigrade at a rate of at least 300 degrees Celsius per hour.Type: GrantFiled: December 9, 1992Date of Patent: January 31, 1995Assignee: Alfred UniveristyInventors: Shyam S. Bayya, Robert L. Synder, Sudhakar Gopalakrishman, Walter A. Schulze
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Patent number: 5376623Abstract: Unexpected results were obtained when Tl-1223 and Tl=-2223 superconductive materials were annealed at respectively pre-determined annealing temperatures. The optimum annealing temperatures for Tl-1223 and Tl-2223 superconductive materials are found to be 860.degree. C. and 820.degree. C., respectively. By incorporating the optimum annealing temperature and an optimum annealing envirenment, which is expressed in terms of oxygen partial pressure, into the manufacturing process, the present invention presents a method which can substantially increase the critical temperature of thallium based superconductive materials with greatly reduced annealing time and with improved reproducibility, and is thus superior to any method disclosed in the prior art.Type: GrantFiled: September 7, 1993Date of Patent: December 27, 1994Assignee: Industrial Technology Research InstituteInventors: Ming-Jinn Tsai, Sheng-Feng Wu, Yao-Tsung Huang, Ru-Shi Liu
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Patent number: 5376626Abstract: A superconducting switch is composed of anisotropic magnetic material. The switch has a first superconducting section, a variable resistive section and a second superconducting section. An external magnetic field is applied so that the first and second superconducting sections remain superconducting and the resistive section changes resistance when the magnetic field applied exceeds the critical field of the variable resistance section. The different critical field regions are achieved by exploiting the natural critical field anisotropy of the ceramic superconductors (a previously unobserved phenomena in metal superconductors). By making the different sections with different orientations they will exhibit different critical field valves for a given direction of applied fields. The state of the switch is changed by either increasing or decreasing the external magnetic field about the critical field value of the resistive section of the switch.Type: GrantFiled: October 2, 1992Date of Patent: December 27, 1994Assignee: The United States of America as represented by the Secretary of the Air ForceInventors: Alvin J. Drehman, Stephen Bachowski
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Patent number: 5376624Abstract: A Josephson break junction device suitable for highly sensitive electronic detecting systems. A superconductor film such as YBa.sub.2 Al.sub.3 O.sub.7 is deposited on a substrate such as a single-crystal MgO. The film is fractured across a narrow strip by at least one indentation in the substrate juxtaposed from the strip to form a break junction. A transducer is affixed to the substrate for applying a bending movement to the substrate to regulate the distance across the gap formed at the fracture to produce a Josephson turned junction effect. Alternatively, or in addition to the transducer, a bridge of a nobel metal is applied across the gap to produce a weak-link junction.Type: GrantFiled: October 10, 1991Date of Patent: December 27, 1994Assignee: The United States of America as represented by the Secretary of the NavyInventors: Ignacio M. Perez, William R. Scott
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Patent number: 5374610Abstract: An insulating composition consisting of Bi, Sr, RE, Cu, O or of Tl, Ba, RE, Cu, O (wherein; RE is an element selected from a group consisting of Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) aligns properly with a crystal face of an oxide superconductor because its crystal structure is the same as or similar to that of the oxide superconductor. An insulating composition in which a part of Bi is replaced by Pb is further near the oxide superconductor its construction, and the modulation structure in this insulating composition is mitigated or disappears.Type: GrantFiled: May 8, 1991Date of Patent: December 20, 1994Assignee: Kabushiki Kaisha ToshibaInventors: Noburu Fukushima, Shunji Nomura, Hisashi Yoshino, Ken Ando, Hiromi Niu, Tomohisa Yamashita
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Patent number: 5372990Abstract: Provided is an oxide superconductor in which superconducting layer is sandwiched between two blocking layers having different compositions. Available superconducting layers include a one-layer system having one Cu-O.sub.2 sheet, a two-layer system having a mediating layer sandwiched between two Cu-O.sub.2 sheets, and a three-layer system having mediating layers sandwiched individually between three Cu-O.sub.2 sheets.Since the blocking layers are of different compositions, seventy-seven kinds of oxide superconductors can be obtained.Type: GrantFiled: May 20, 1992Date of Patent: December 13, 1994Assignee: Toray Industries, Ltd.Inventors: Hitoshi Nobumasa, Kazuharu Shimizu
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Patent number: 5354921Abstract: There is disclosed a single crystalline fibrous superconductive composition represented by the atomic compositional formula: Bi.sub.2 Sr.sub.2 CaCu.sub.2 M.sub.X O.sub.Y wherein 0<X<0.5; 7.8<Y<8.5; and M is at least one member selected from the group consisting of Pb, Sn, Sb, In, Cd, Ga, Ge, K, Li, and Na. This composition is prepared by a process comprising the step of mixing source material with one another to prepare a mixture having an atomic compositional ratio: Bi=1.00, Sr=0.5.about.2.0, Ca=0.5.about.5.0, Cu=1.0.about.7.0, and M=0.1.about.1.0, wherein M is at least one member selected from the group consisting of Pb, Sn, Sb, In, Cd, Ga, Ge, K, Li, and Na, the step of melting the mixture to prepare a molten material having an atomic compositional ratio: Bi=1.00, Sr=0.5.about.2.0, Ca=0.5.about.5.0, Cu=1.0.about.7.0, M=0.1.about.1.0, and O=3.5.about.8.Type: GrantFiled: August 26, 1993Date of Patent: October 11, 1994Assignee: Agency of Industrial Science & TechnologyInventors: Ichiro Matsubara, Hideo Tanigawa, Toru Ogura, Hiroshi Yamashita, Makoto Kinoshita
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Patent number: 5352657Abstract: A bismuth system oxide superconductor comprising the 110 K phase is effectively prepared by a process comprising the steps of mixing a bismuth compound, a strontium compound, a calcium compound, a copper compound and optionally a lead compound, optionally provisionally sintering the mixture, and sintering the mixture.Type: GrantFiled: April 9, 1992Date of Patent: October 4, 1994Assignee: Daikin Industries Ltd.Inventors: Utako Endo, Satoshi Koyama, Kazuo Okamura, Tomoji Kawai, Koichi Kitazawa
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Patent number: 5346538Abstract: Alkaline earth metal indates of the formula (Sr,Ca)In.sub.2 O.sub.4 can be converted by sintering or fusing into compact moldings which, owing to their stability are suitable even at temperatures of at least 800.degree. C. as reaction vessels for chemical reactions in the presence of bismuth (III) oxide and/or alkaline earth metal oxides.Type: GrantFiled: June 27, 1991Date of Patent: September 13, 1994Assignee: Hoechst AktiengesellschaftInventor: Winfried Becker
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Patent number: 5340796Abstract: Novel superconductive oxides are disclosed. The oxides all have layered perovskite-like crystal structure and manifest superconductivity above about 77K. An exemplary material has composition Bi.sub.2.2 Sr.sub.2 Ca.sub.0.8 Cu.sub.2 O.sub.8. Other materials are described by the nominal formula X.sub.2+x M.sub.n-x Cu.sub.n-1 O.sub.2+2n+x/2.+-..delta., where X typically is Bi, or Bi together with Pb or other appropriate substituent, M is one or more divalent ion or mixture of monovalent and trivalent ion, n is an integer greater than 3, x=p/q, where p and q are integers and p<q, and .delta. is less than 0.5. Associated with the inventive compounds typically is a superlattice structure, with T.sub.c of the compound typically being correlated with the superlattice spacing. The inventive compounds are typically relatively ductile.Type: GrantFiled: November 13, 1992Date of Patent: August 23, 1994Assignee: AT&T Bell LaboratoriesInventors: Robert J. Cava, Steven A. Sunshine
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Patent number: 5324712Abstract: A process for producing a high critical temperature bismuth strontium calcium copper oxide superconducting material. An intimate mixture is formed of two superconducting materials. The first material is bismuth strontium calcium copper oxide or (bismuth, lead) strontium calcium copper oxide, and has a bulk critical temperature below about 90K. The second material is a seeding powder of bismuth strontium calcium copper oxide or (bismuth, lead) strontium calcium copper oxide, and includes at least 20 volume percent 2223 phase. The amount of seeding material added to the mixture is selected to result in an amount of 2223 phase in the mixture of about 2-50 weight percent. The mixture is annealed in an oxidizing atmosphere at a temperature of at least about 845.degree. C. and below the melting temperature of the 2223 phase, for a time sufficient to increase the amount of 2223 phase in the mixture.Type: GrantFiled: August 16, 1991Date of Patent: June 28, 1994Assignee: GTE Laboratories IncorporatedInventor: Sophia R. Su
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Patent number: 5317007Abstract: A high-Tc oxide superconductor including Bi, Sr, Ca, Cu, O and at least one of Pb and Al, with a high critical temperature than that of liquid nitrogen. A method for producing the high-Tx oxide superconductor is also disclosed, in which Bi.sub.2 O.sub.3, SrCO.sub.3, CaCO.sub.3, CuO and PbO or Al.sub.2 O.sub.3 powders are mixed, calcined, ground, cold-pressed and sintered. The calcined mixture may be melted and annealed to obtain a tape-form superconductor.Type: GrantFiled: June 29, 1992Date of Patent: May 31, 1994Assignee: Kabushiki Kaisha ToshibaInventors: Yutaka Yamada, Satoru Murase
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Patent number: 5317008Abstract: A method of manufacturing a bismuth oxide superconductor, wherein a molded body of a bismuth oxide superconducting substance comprising bismuth, an alkaline earth metal, copper, and oxygen or a precursor thereof is subjected to a heat treatment for producing a superconducting phase and then subjected to one step selected from (1) a step of cooling the heated body from 700.degree. C. to 200.degree. C. in an atmosphere having an oxygen partial pressure of not less than 0.1 atm at a cooling rate of not less than 10.degree. C./min, (2) a step of cooling the heated body from 700.degree. C. in an atmosphere having an oxygen partial pressure of less than 0.1 atm at a cooling rate of less than 10.degree. C./min, and (3) a step of cooling the heated body, and then performing a heat treatment for the cooled heated body in an atmosphere having an oxygen partial pressure of not more than 0.1 atm at a temperature from 700.degree. C. to 200.degree. C.Type: GrantFiled: January 22, 1993Date of Patent: May 31, 1994Assignee: The Furukawa Electric Co., Ltd.Inventor: Kumiko Imai
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Patent number: 5306705Abstract: A non-linear superconducting junction device comprising a layer of high transient temperature superconducting material which is superconducting at an operating temperature, a layer of metal in contact with the layer of high temperature superconducting material and which remains non-superconducting at the operating temperature, and a metal material which is superconducting at the operating temperature and which forms distributed Sharvin point contacts with the metal layer.Type: GrantFiled: May 6, 1993Date of Patent: April 26, 1994Assignee: Board of Trustees of the Leland Stanford Junior UniversityInventors: Matthew J. Holcomb, William A. Little
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Patent number: 5300486Abstract: A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi.sub.a Pb.sub.b Sr.sub.c Ca.sub.d Cu.sub.e O.sub.f wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10.+-.z by reacting a mixture of Bi.sub.4 Sr.sub.3 Ca.sub.3 Cu.sub.4 O.sub.16.+-.z, an alkaline earth metal cuprate, e.g., Sr.sub.9 Ca.sub.5 Cu.sub.24 O.sub.41, and an alkaline earth metal plumbate, e.g., Ca.sub.2-x Sr.sub.x PbO.sub.4 wherein x is about 0.5, is disclosed.Type: GrantFiled: May 27, 1993Date of Patent: April 5, 1994Assignee: The United States of America as represented by the United States Department of EnergyInventors: William L. Hults, Kimberly A. Kubat-Martin, Kenneth V. Salazar, David S. Phillips, Dean E. Peterson
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Patent number: 5296455Abstract: A compound oxide superconductor represented by the general formula:Bi.sub.4+d (Sr.sub.1-x, Ca.sub.x).sub.m Cu.sub.n O.sub.p+yin which,"d" is an amount of excess bismuth and satisfies a range of 0<d.ltoreq.1.2,"m" is a number which satisfies a range of 6.ltoreq.m.ltoreq.10,"n" is a number which satisfies a range of 4.ltoreq.n.ltoreq.8,"p"=6+m+n,"x" is a number which satisfies a range of 0<x<1, and"y" is a number which satisfies a range of -2.ltoreq.<y.ltoreq.+2.A preferred example is a compound oxide system having the following general formula:Bi.sub.4+d Sr.sub.4 Ca.sub.4 Cu.sub.6 O.sub.20+yin which "d" is a number which satisfies the range 0.4.ltoreq.d.ltoreq.1.2 and "y" is a number which satisfies a range of -2.ltoreq.y.ltoreq.+2. The critical current density (J.sub.c) is improved by increasing the amount of bismuth with respect to the stoichiometric amount. A superconducting thin film is deposited on a substrate by physical vapor deposition such as sputtering.Type: GrantFiled: May 7, 1992Date of Patent: March 22, 1994Assignee: Sumitomo Electric Industries, Ltd.Inventors: Keizo Harada, Hideo Itozaki, Kenjiro Higaki, Shuji Yazu
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Patent number: 5294601Abstract: The invention relates to a high-temperature superconductor composed of the oxides of bismuth, strontium, calcium and copper and, optionally, of lead, and having the composition Bi.sub.2-a+b+c Pb.sub.a (Sr, Ca).sub.3-b-c Cu.sub.2+d O.sub.x, where a=0 to 0.7; b+c=0 to 0.5; d=-0.1 to 0.1 and x=7 to 10 and a Sr:Ca ratio of 2.8:1 to 1:2.8 as well as of strontium and/or barium sulfates. Said superconductor can be prepared by intimately mixing the oxides of bismuth, strontium, calcium and copper and optionally of lead with strontium and/or barium sulfates, melting the mixture by heating to temperatures of 870 to 1300.degree. C., higher temperatures being required for higher strontium and/or barium sulfate contents, pouring the melt into molds and allowing it to solidify slowly therein and subjecting the moldings removed from the molds to a heat treatment at temperatures of 700 to 900.degree. C. in an oxygen-containing atmosphere.Type: GrantFiled: July 10, 1992Date of Patent: March 15, 1994Assignee: Hoechst AktiengesellschaftInventors: Joachim Bock, Eberhard Preisler
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Patent number: 5264414Abstract: Compositions having the formula Tl.sub.1-x Bi.sub.x Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.9 wherein x is from about 3/20 to about 11/20 are superconducting with transition temperatures above 110 K. Processes for making and using the compositions of the invention are provided.Type: GrantFiled: September 25, 1992Date of Patent: November 23, 1993Assignee: E. I. Du Pont de Nemours and CompanyInventor: Munirpallam A. Subramanian
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Patent number: 5264413Abstract: Compounds of the formula Bi.sub.1 Sr.sub.2 Ca.sub.n-1 Cu.sub.n O.sub.Type: GrantFiled: January 27, 1992Date of Patent: November 23, 1993Inventors: Ivan Bozovic, James N. Eckstein
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Patent number: 5258363Abstract: A high efficiency integrating sphere that can be used in a large variety of scientific instruments. The sphere having an efficiency gain obtained by using a superconducting material, acting as a perfect reflector, on the inside hollow surface of the sphere. The sphere is operated with a delay between the incident and sensed light, heretofore not possible, and yielding substantial improvement in the signal-to noise ratio of the integrating sphere.Type: GrantFiled: March 21, 1989Date of Patent: November 2, 1993Assignee: Troy Investments Inc.Inventor: Aharon Z. Hed
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Patent number: 5250509Abstract: The invention relates to an oxide-ceramic superconducting material which contains bismuth, strontium, calcium and copper, having an overall composition of Bi.sub.y Ca.sub.2 Sr.sub.2 Cu.sub.3 O.sub.x, where y is an integer from 2.35 to 2.6 and x is about 10 to 12. The material has a critical temperature T above 105 K and has a proportion of the phase Bi.sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x of at least 85% by volume. The invention also relates to a process for producing a bismuth-containing superconducting material which comprises holding the oxides or oxide precursors of bismuth, strontium, calcium and copper at a temperature in the range from 850.degree. to 890.degree. C. over a time span of a plurality of hours and adhering to the following atomic ratios:Bi:Cu>2:3Ca:Sr=0.9 to 1.50.SIGMA.(Sr+Ca):Cu=4.2:3 to 4:3.33Bi:.SIGMA.(Sr+Ca)=2.35:4 to 3.Type: GrantFiled: February 20, 1992Date of Patent: October 5, 1993Assignee: Hoechst AktiengesellschaftInventors: Bernhard Hettich, Peter Majewski, Klaus Schulze, deceased, Gunter Petzow
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Patent number: 5244873Abstract: A process for preparing a single crystal thin film made of oxide superconductor of Bi, Sr, Ca, and Cu on a substrate by a sputtering method using a target made of a sintered oxide of Bi, Sr, Ca, and Cu and having its c-axis oriented in parallel with the surface of the substrate.The sputtering is effected by 90.degree. off-axis magnetron sputtering at a substrate temperature between 500.degree. C. and 750.degree. C. at a gas pressure between 0.001 Torr and 1 Torr.Type: GrantFiled: November 21, 1991Date of Patent: September 14, 1993Assignee: Sumitomo Electric Industries, Ltd.Inventors: Hisao Hattori, Kenjiro Higaki, Hideo Itozaki
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Patent number: 5244876Abstract: Method for joining parts of ceramic high-temperature superconductor material of the composition Bi.sub.(2+a-b) (Sr.sub.1-c) Ca.sub.c) .sub.(3-a) Pb.sub.b Cu.sub.(2+d) O.sub.x, where a is 0 to 0.3, b is 0 to 0.5, c is 0.1 to 0.9 and d is 0 to 2 and x has a value depending on the state of oxidation of the metals present, the end faces of the parts located at a gap spacing apart from one another are heated by means of a fuel gas/oxygen flame to temperatures from 750.degree. to 875.degree. C. Simultaneously, a rod of the same material above the spacing gap is heated until the melt thereof drips off into the gap between the end faces of the two parts, completely filling the gap. At least the joint region between the two parts is then heat-treated for 7 to 100 hours at temperatures between 780.degree. and 850.degree. C.Type: GrantFiled: October 26, 1992Date of Patent: September 14, 1993Assignee: Hoechst AktiengesellschaftInventors: Eberhard Preisler, Joachim Bock, Johannes Holzem, Werner Horst
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Patent number: 5242897Abstract: Complex superconducting oxides are fabricated through appropriate selection and use of fundamental superconducting "building blocks." In this fashion, the invention provides a rationalized method of fabricating complex oxides having desirably high T.sub.c values. In another aspect of the invention, novel, 112 and 12 superconducting oxides are described.Type: GrantFiled: October 28, 1991Date of Patent: September 7, 1993Assignee: The University of KansasInventors: Kai W. Wong, Xin Fei
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Patent number: 5238911Abstract: An oxide superconductor of the formula: Bi.sub.1.0 Sr.sub.A Ca.sub.B Mg.sub.C Ba.sub.D Cu.sub.1.0.+-.0.15 O.sub.X wherein A=0.6-1.3, B=0.3-0.9, C=0.01-0.3 and D=0.01-0.3 in atomic ratio, having a 2212 phase with a critical temperature of making electrical resistance zero at about 80K or more, can be produced by firing preferably at 820.degree.-870.degree. C. in a lower oxygen content atmosphere.Type: GrantFiled: April 2, 1991Date of Patent: August 24, 1993Assignee: Hitachi Chemical Company Ltd.Inventors: Hidegi Kuwajima, Keiji Sumiya, Shuichiro Shimoda, Toranosuke Ashizawa, Minoru Ishihara, Shozo Yamana
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Patent number: 5238914Abstract: The invention relates to a process for producing a bismuth-, copper-, strontium- and calcium-containing high-temperature superconductor, in which an aqueous solution is produced which has a pH of 0.5-4 and which contains the metals in an atomic ratio corresponding to a high-temperature superconductor, the solution is combined with an oxalic acid solution to precipitate the metals quantitatively as oxalates, the oxalates formed are separated off and decomposed thermally to form the oxides and the latter are reacted in the presence of oxygen at temperatures above 700.degree. C. to form the desired high-temperature superconductor. The process comprises concentrating the aqueous solution of the metal until a precipitate begins to appear and using the oxalic acid as a solution in an organic solvent which is miscible with water The oxalates are decomposed at 550-700.degree. C. in the presence of oxygen.Type: GrantFiled: July 9, 1992Date of Patent: August 24, 1993Assignee: Hoechst AktiengesellschaftInventors: Christoph Lang, Winfried Becker, Carsten Budesheim
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Patent number: 5236889Abstract: 1. In the (Bi,Tl)-Ca-(Sr,Ba)-Cu-O based superconducting ceramics production process, a process for preparing superconducting ceramics characterized by(a) providing powders includingi) a compound of Bi oxide or Tl oxide,ii) a Ca compound,iii) an Sr compound or Ba compound, andiv) a Cu compoundas starting powders;(b) compounding and mixing powders from compounds of the starting powders, the compounds each having lower vapor pressure, i.e., powders from compound ii), compound iii), and compound iv) at a compounding ratio to obtain a mixture, and primarily calcining the mixture at a temperature of 850.degree. to 1050.degree. C., to form a Ca--(Sr,Ba)--Cu--O based oxide; and(c) further mixing the Ca--(Sr,Ba)--Cu--O based oxide with a compound having a higher vapor pressure, that is, the powder of compound i), at a compounding ratio, and secondarily calcining at a temperature of 500.degree. to 820.degree. C.Type: GrantFiled: November 27, 1989Date of Patent: August 17, 1993Assignee: Mitsubishi Materials CorporationInventors: Tadashi Sugihara, Takuo Takeshita, Yukihiro Ouchi, Takeshi Sakurai
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Patent number: 5236891Abstract: Disclosed herein is a method of preparing a bismuth oxide superconductor by forming a superconducting phase having a 2223 composition or a 2212 composition in a composition of Bi-Sr-Ca-Cu or (Bi,Pb)-Sr-Ca-Cu in a metal sheath. This method comprises the steps of preparing raw material powder containing a mixture of a 2212 phase having the 2212 composition and non-superconducting phases, carrying out a process of heat treating the raw material powder under a reduced pressure of not more than 1 atm. immediately before filling the same into the metal sheath and thereafter cooling the same under an oxygen atmosphere, and filling the raw material powder into the metal sheath and thereafter performing deformation processing and heat treatment on the metal sheath. This method is suitable for preparation of a long wire.Type: GrantFiled: August 8, 1991Date of Patent: August 17, 1993Assignee: Sumitomo Electric Industries, Ltd.Inventors: Takeshi Hikata, Kenichi Sato
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Patent number: 5229035Abstract: A Bi-Pb-Sr-Ca-Cu-O system superconductor having a composition ofBi.sub.n Pb.sub.m Sr.sub.x Ca.sub.y Cu.sub.2 O.sub..delta.wherein n is a number from 0.76 to 1.05, m is a number from 0.01 to 0.20, x is a number from 0.85 to 1.35 and y is a number larger than 1.00 and not larger than 1.35; or n is a number larger than 1.06 and not larger than 1.15, m is a number from 0.12 to 0.25, x is a number from 1.20 to 1.35 and y is a number from 1.20 to 1.30; or n is a number larger than 0.75 and not larger than 1.15, m is a number from 0.25 to 0.35, x is a number from 1.20 to 1.35 and y is a number from 1.20 to 1.35, when they are normalized with the Cu mole number of 2, which has t.sub.c of at least 110 K.Type: GrantFiled: May 28, 1991Date of Patent: July 20, 1993Assignees: Toda Kogyo Corporation, NEC Corporation, Tosoh Corporation, Osaka Cement Co., Ltd., Kabushiki Kaisha Kobe Seiko Sho, Seisan Kaihatsu Kagaku KenkyushoInventors: Toshio Takada, Mikio Takano, Yoshinari Miura, Jun Takada, Kiichi Oda, Naoichi Yamamoto
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Patent number: 5217946Abstract: Superconductors having a composition Bi.sub.2-a-b-c Sn.sub.a Pb.sub.b Sb.sub.c Sr.sub.2 Ca.sub.n-1 Cu.sub.n O.sub.2n+4 can be made by firing the appropriate mixtures of designated oxides or carbonates. In the composition a=about 0.001-0.4, b about 0-0.4, c about 0-0.4, and n 2 or 3. The addition of Sn improves the superconductive properties of comparable compositions that lack Sn. For example, Bi.sub.1.6 Sn.sub.0.4 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x (x=ca 10), calcined at 830.degree. C. for 15 hours shows superconductivity by magnetic susceptibility tests at about 77.degree. K. whereas Bi.sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.10 prepared under the same conditions but lacking Sn, shows nothing at this temperature.Type: GrantFiled: May 1, 1989Date of Patent: June 8, 1993Assignee: W. R. Grace & Co.-Conn.Inventor: Leonard E. Dolhert
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Patent number: 5215961Abstract: A machinable high Tc ceramic superconductor is formed by weighing and mixing appropriate stoichiometric amounts of Bi.sub.2 O.sub.3, SrCO.sub.3, CaCO.sub.3, and CuO (BSCCO), removing carbonates from the mixture, melting the mixture, casting the melted mixture into a mold, and inducing superconductivity and growth of randomly oriented platelets in the cast.Type: GrantFiled: June 25, 1990Date of Patent: June 1, 1993Assignee: The United States of America as represented by the Secretary of the NavyInventors: Roy J. Rayne, Louis E. Toth, L. David Jones, Robert J. Soulen, Jr., Barry A. Bender
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Patent number: 5208214Abstract: An oxide ceramic superconductor can be obtained if the oxides of bismuth, strontium, calcium and copper are mixed, the atomic ratios of the metals corresponding to a high-temperature superconductor, the mixture is mixed with an alkaline earth metal indate powder of the formula (Sr,Ca)In.sub.2 O.sub.4 and the mixture is heated for a prolonged period in the presence of oxygen. The presence of the indate promotes the development of a phase having a critical temperature of 110K.Type: GrantFiled: August 19, 1991Date of Patent: May 4, 1993Assignee: Hoechst AktiengesellschaftInventor: Winfried Becker
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Patent number: 5204317Abstract: A method for making a high critical current density Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8 superconductor includes mixing suitable solid state reactants in amounts sufficient to create a reactant mixture having a ratio of approximately 4 Bi atoms:3 Ca atoms:3 Sr atoms:4 Cu atoms and oxygen. The reactant mixture is heated to a sufficient temperature for a sufficient time to sinter the reactant mixture and form a Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8 superconductor.Type: GrantFiled: July 29, 1991Date of Patent: April 20, 1993Assignee: United Technologies CorporationInventors: Francis S. Galasso, David A. Condit
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Patent number: 5202306Abstract: An oxide-based strengthening and toughening agent, such as tetragonal Zro.sub.2 particles, has been added to copper oxide superconductors, such as superconducting YBa.sub.2 Cu.sub.3 O.sub.x (123) to improve its fracture toughness (K.sub.IC). A sol-gel coating which is non-reactive with the superconductor, such as Y.sub.2 BaCuO.sub.5 (211) on the ZrO.sub.2 particles minimized the deleterious reactions between the superconductor and the toughening agent dispersed therethrough. Addition of 20 mole percent ZrO.sub.2 coated with 211 yielded a 123 composite with a K.sub.IC of 4.5 MPa(m).sup.0.5.Type: GrantFiled: September 18, 1991Date of Patent: April 13, 1993Assignee: The United States of America as represented by the United States Department of EnergyInventors: Kenneth C. Goretta, Marc L. Kullberg
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Patent number: 5194421Abstract: The present invention provides an oxide superconductor which is mainly composed of bismuth, lead, strontium, calcium, magnesium, and copper and has the composition represented by the formula:Bi.sub.1-A Pb.sub.A Sr.sub.1-B Mg.sub.B Ca.sub.1 Cu.sub.1.7.+-.0.3 Oxwherein A=0.15-0.35 and B=0.05-0.3 in which numerals represent atomic ratio and an oxide superconductor which is mainly composed of bismuth, lead, strontium, calcium, magnesium, barium and copper and has the composition represented by the formula:Bi.sub.1-A Pb.sub.A Sr.sub.1-(B+C) (Mg.sub.B Ba.sub.C)Ca.sub.1 Cu.sub.1.7.+-.0.3 Oxwherein A=0.15-0.35, B=0.05-0.3 and C=0.02-0.2 in which numerals represent atomic ratio. Methods for producing these superconductors are also provided.Type: GrantFiled: November 20, 1991Date of Patent: March 16, 1993Assignee: Hitachi Chemical CompanyInventors: Shuichiro Shimoda, Toranosuke Ashizawa, Keiji Sumiya, Hideji Kuwajima, Minoru Ishihara, Shozo Yamana