Patents Assigned to International Superconductivity Technology Center
-
Patent number: 5534490Abstract: Provided is an Hg-Ba-Ca-Cu-O oxide superconductor having a high superconductivity transition temperature Tc and a method which can prepare the same in excellent reproducibility. This oxide superconductor consists essentially of Hg, Ba, Ca, Cu and O, and is expressed in a chemical formula (Hg.sub.1-X Cu.sub.X)Ba.sub.2 Ca.sub.2 Cu.sub.3 O.sub.Y, wherein X=0.05 to 0.7 and Y=8 to 8.75. A method of preparing the oxide superconductor comprises a step of mixing raw materials of Hg, Ba, Ca and Cu with each other so that (Hg+Ba):Ca:Cu=b:1:C and Hg:Ba=(1-a):a, wherein 0.625.ltoreq.a.ltoreq.0.714, 1.ltoreq.b.ltoreq.3 and 1.667.ltoreq.c.ltoreq.3.444, in mole ratio, and compression-molding the mixture, and a step of heat treating a compact obtained by the compression molding. This oxide superconductor has a superconductivity transition temperature Tc of 134 K., which is the highest at present.Type: GrantFiled: June 23, 1994Date of Patent: July 9, 1996Assignees: Sumitomo Electric Industries, Ltd., Tohoku Electric Power Co., Inc., Matsushita Electric Industrial Co., Ltd., International Superconductivity Technology CenterInventors: Makoto Itoh, Ayako Yamamoto, Kazuyuki Isawa, Seiji Adachi, Hisao Yamauchi, Shoji Tanaka
-
Patent number: 5534638Abstract: This describes the following five novel organic substances: Bis (ethylenedithio) tetrathiafulvalene (henceforth to be called BEDT-TTF) compounded with cyanometalate anions in what is called Tetracyano Nickel acid Bis (Ethylenedithio) Tetrathiafulvalene salt.hydrate expressed by (BEDT-TTF).sub.4 [Ni(CN).sub.4 ].H.sub.2 O, Tetracyano Platinum acid Bis (Ethylenedithio) Tetrathiafulvalene salt.hydrate that is expressed by (BEDT-TTF).sub.4 [Pt(CN).sub.4 ].H.sub.2 O, Cyanide Palladium Bis (Ethylenedithio) Tetrathiafulvalene salt that is expressed by (BEDT-TTF)-[Pd(CN).sub.2 ], Tetracyano Palladium acid Bis (Ethylenedithio) Tetrathiafulvalene salt.hydrate that is expressed by (BEDT-TFF).sub.4 [Pd(CN).sub.4 ].H.sub.2 O and Tetracyano Palladium acid Bis (Ethylenedithio) Tetrathiafulvalene salt that is represented by (BEDT-TTF).sub.4 [Pd(CN).sub.4 ]. BEDT-TTF, acting as a common constituent in the crystals of all of the above substances, provides the properties of an insulator, a metal or a superconductor.Type: GrantFiled: April 26, 1995Date of Patent: July 9, 1996Assignee: International Superconductivity Technology CenterInventors: Hatsumi Mori, Izumi Hirabayashi, Shoji Tanaka, Takehiko Mori, Yusei Maruyama, Hiroo Inokuchi
-
Patent number: 5525584Abstract: A high critical temperature and high critical current density superconductor is disclosed which contains a metal oxide expressed by the following formula (I):(R.sup.1.sub.1-x,Ba.sub.x)Ba.sub.2 Cu.sub.3 O.sub.d (I)wherein R.sup.1 stands for at least one element selected from the group consisting of La, Nd, Sm, Eu and Gd, x is a number greater than 0 but not greater than 0.5 and d is a number between 6.2 and 7.2. Fine phases of RE211, RE422 and/or a metal oxide expressed by the formula (R.sup.2.sub.1-z, Ba.sub.z) (Ba.sub.1-y, R.sup.2.sub.y).sub.2 Cu.sub.3 O.sub.p (R.sup.2 =La, Nd, Sm, Eu or Gd) may be dispersed in a matrix of the matrix phase of the formula (I). The above superconductor may be obtained by cooling a melt having a temperature of 1,000.degree.-1,300.degree. C. and containing R.sup.1, Ba, Cu and O at a cooling rate of 5.degree. C./hour or less under a partial pressure of oxygen of between 0.00001 and 0.05 atm, followed by annealing at 250.degree.-600.degree. C. in an oxygen atmosphere.Type: GrantFiled: May 26, 1995Date of Patent: June 11, 1996Assignees: International Superconductivity Technology Center, Railway Technical Research Institute, Shikoku Denryoku Kabushikigaisha, Tosoh CorporationInventors: Masato Murakami, Sang-Im Yoo, Naomichi Sakai, Hiroshi Takaichi, Takamitsu Higuchi, Shoji Tanaka
-
Patent number: 5521150Abstract: Disclosed is a method of joining Y-based oxide superconductors on joining two or more Y-based oxide superconductors made by melting process under pressure, characterized by incorporating REBa.sub.2 Cu.sub.3 O.sub.7-.delta. (RE=Y, Ho, Er, Tm or Yb), Ag and BaCuO.sub.2 -CuO type composition to the joining interface as an adhesive phase for joining. It becomes possible to easily make a joined material that does not deteriorate the superconductive characteristic at joined interface.Type: GrantFiled: September 15, 1994Date of Patent: May 28, 1996Assignees: International Superconductivity Technology Center, Shikoku Denryoku Kabushiki KaishaInventors: Masato Murakami, Hiroshi Takaichi, Naomichi Sakai
-
Patent number: 5512541Abstract: The present invention is directed to a method for growing a superconductive film on a superconductive substrate in order to produce a bulk single crystal. According to a preferred embodiment, an oxide superconductive film of a material which is the same or similar to the substrate material is epitaxially grown at a temperature between 450.degree. C. and 800.degree. C. so that the film and substrate have the same lattice orientations. According to the present invention, problems associated with conventional films having non-superconductor substrates (e.g., MgO and SrTiO.sub.3) are avoided.Type: GrantFiled: September 12, 1994Date of Patent: April 30, 1996Assignees: Sumitomo Electric Industries, Ltd., International Superconductivity Technology CenterInventors: Masaya Konishi, Kunihiko Hayashi, Youichi Enomoto, Shoji Tanaka, Yasuji Yamada, Kanshi Ohtsu, Yasuo Kanamori, Yuh Shiohara
-
Patent number: 5504226Abstract: In the production of a 124-type or 123-type superconductor by a sol-gel method using alkoxides of respective metals, the use of a compound wherein a sec-butoxy group and a hydroxy group are coordinated with a copper atom gives a superconductor composed of flat particles having a broad C plane. The dimensional ratio defined by l/d is at least 6.7 in the case of the 124-type or is at least 8.4 in the case of the 123-type. It shows a superconducting property at a liquid nitrogen temperature. This superconductor shows a higher critical current density than one obtained by a sintering method.Type: GrantFiled: November 23, 1994Date of Patent: April 2, 1996Assignees: Kyocera Corporation, International Superconductivity Technology Center, Sanyo Electric Co., Ltd.Inventors: Shinichi Koriyama, Takaaki Ikemachi, Hisao Yamauchi
-
Patent number: 5496799Abstract: A method for making a rare earth superconductive composite which includes a matrix of REBa.sub.2 Cu.sub.3 O.sub.7-x grains and fine particles of RE.sub.2 BaCuO.sub.5 dispersed therein. The method includes a step of forming a compacted mass of powder particles of REBa.sub.2 Cu.sub.3 O.sub.7-x and powder particles of RE.sub.2 BaCuO.sub.5, each of which has an average diameter not greater than 6 .mu.m, and a maximum diameter not greater than 20 .mu.m. The compacted mass is heated to temperature higher than an incongruent melting temperature of the REBa.sub.2 Cu.sub.3 O.sub.7-x and lower than an incongruent melting temperature of RE.sub.2 BaCuO.sub.5, and is gradually cooled such that fine particles of RE.sub.2 BaCuO.sub.5 are dispersed in REBa.sub.2 Cu.sub.3 O.sub.7-x grains. The mass is annealed in an atmosphere containing oxygen.Type: GrantFiled: December 29, 1994Date of Patent: March 5, 1996Assignees: NGK Insulators, Ltd., International Superconductivity Technology CenterInventors: Manabu Yoshida, Izumi Hirabayashi
-
Patent number: 5474976Abstract: A method for producing an REBaCuO oxide superconductor having large magnetic levitation force, where RE is a rare earth element selected from the group consisting of Y, Sm, Eu, Gd, Dy, Ho, Er, and Yb, involves the steps of using a raw material mixture as the starting feed, heating the raw material mixture for partial melting, followed by cooling and solidification, pulverizing and mixing the resulting solid, shaping the resulting mixture into a given shape, placing or embedding nucleates on or in the resulting shape, followed by heating for partial melting, and cooling the resulting partial melt to a substantial temperature at which a superconducting phase starts to form, followed by slow cooling, whereby the superconducting phase is preferentially formed and grown from a nucleation site.Type: GrantFiled: March 29, 1993Date of Patent: December 12, 1995Assignees: International Superconductivity Technology Center, Kawasaki Jukogyo Kabushiki Kaisha, Hokuriku Electric Power Co., Nippon Steel CorporationInventors: Akihiro Kondoh, Masato Murakami, Hiroshi Takaichi, Naoki Koshizuka, Shoji Tanaka, Shoichi Kagiya
-
Patent number: 5468806Abstract: Disclosed is a method of manufacturing a thin film of an oxide superconductor represented by formula Sr.sub.1-x Nd.sub.x CuO.sub.2 on a substrate. The oxide superconductor has a tetragonal crystal structure, the lattice constant in a-axis falling within a range of between 0.385 nm and 0.410 nm, and the lattice constant in c-axis being an integer number of times as much as a level falling within a range of between 0.310 nm and 0.350 nm. The method includes the steps of forming by epitaxial growth a film of a crystal having lattice constants close to those of the crystal of said oxide superconductor on a substrate, and forming a thin film of the oxide superconductor of a tetragonal crystal structure represented by general formula (I) by a thin film-forming technique.Type: GrantFiled: December 1, 1994Date of Patent: November 21, 1995Assignees: The Furukawa Electric Co., Ltd., Hitachi Ltd., Kabushiki Kaisha Toshiba, Central Research Institute of Electric Power Industry, International Superconductivity Technology CenterInventors: Kiyoshi Yamamoto, Nobuyuki Sugii, Koichi Kubo, Michiharu Ichikawa, Hisao Yamauchi
-
Patent number: 5468724Abstract: Disclosed herein are high-temperature oxide superconductors of RBa.sub.2 Cu.sub.4 O.sub.8 type, with Ba partly replaced by Sr or Ca, or with R and Ba partly replaced by Ca and Sr, respectively, as represented by the chemical composition formula of R(Ba.sub.1-y Sr.sub.y).sub.2 Cu.sub.4 O.sub.8 or R(Ba.sub.1-z Ca.sub.z).sub.2 Cu.sub.4 O.sub.8 or (R.sub.1-x Ca.sub.x) (Ba.sub.1-y Sr.sub.y).sub.2 Cu.sub.4 O.sub.8. They exhibit superconductivity at high temperatures. Especially, the last one exhibits superconductivity at a higher temperature than the former two. All of them can be made with a less amount of Ba as a deleterious substance, and the first two have improved sinterability. The best results are obtained when they are produced by the process involving the hot hydrostatic pressure treatment of the mixture of raw materials at 850.degree.-1100.degree. C. in an atmosphere composed of an inert gas and oxygen. The process permits a wider selection of Ba raw materials.Type: GrantFiled: May 27, 1993Date of Patent: November 21, 1995Assignees: International Superconductivity Technology Center, Matsushita Electric Industrial Co., Ltd., Kyocera Corporation, Mitsubishi Metal Corporation, The Tokyo Electric Power Company, Incorporated, Kabushiki Kaisha Kobe Seiko ShoInventors: Takahiro Wada, Shin-ichi Koriyama, Takeshi Sakurai, Nobuo Suzuki, Takayuki Miyatake, Hisao Yamauchi, Naoki Koshizuka, Shoji Tanaka
-
Patent number: 5466665Abstract: A method of manufacturing YBCO superconducting thin films is obtained which is capable of providing superconducting thin films having excellent crystallinity in a high yield by introducing a new film formation parameter in a hybrid plasma sputtering method. When a Y--Ba--Cu--O type superconducting thin film is formed by using a parallel plate sputtering method, a high-frequency voltage generated by a high-frequency power source is superimposed on a DC voltage generated by a DC power source and applied to the cathode electrode at the same time, an electrically conductive YBCO target is placed on the cathode, and the film formation conditions are controlled on the basis of the difference between the voltage drops in each ion sheath formed on the substrate and directly on the target by applying a DC voltage to a substrate holder from the DC power source.Type: GrantFiled: June 16, 1994Date of Patent: November 14, 1995Assignees: Mitsubishi Denki Kabushiki Kaisha, Nippon Steel Corporation, International Superconductivity Technology CenterInventors: Yukihisa Yoshida, Wataru Ito, Tadataka Morishita
-
Patent number: 5459124Abstract: A process for producing an oxide superconductor, comprising putting a formed body of raw material powders for forming an oxide superconductor on silver or silver oxide within a pan which does not melt at the melting point of silver, heating the pan to a temperature higher than the melting point of silver to bring the formed body to a semi-molten state with the formed body being floated on molten silver, cooling the pan and taking the formed body out of the re-solidified silver. This process enables a large bulk material having a diameter of 10 cm or more to be produced without occurrence of cracking.Type: GrantFiled: October 29, 1993Date of Patent: October 17, 1995Assignees: International Superconductivity Technology Center, Shinkoku Electric Power Co., Inc., Nippon Steel CorporationInventors: Terutsugu Oyama, Masato Murakami, Naoki Koshizuka, Shoji Tanaka
-
Patent number: 5453306Abstract: The generation of a reaction product is suppressed between a metallic substrate and plasma in depositing a ceramic intermediate layer on the metallic substrate in a process for depositing an oxide film on the metallic substrate by thermal plasma flash evaporation method. Thus, there is no reaction phase in the ceramic intermediate layer and the metallic substrate, and an intermediated buffer layer of only oxide ceramic is deposited on a flat surface of the metallic substrate. The intermediate ceramic layer is deposited in inert atmosphere of a low oxygen concentration at a temperature of less than 600.degree. C. for the metallic substrate. Then, a superconducting thin film is deposited on the ceramic intermediate layer.Type: GrantFiled: June 30, 1994Date of Patent: September 26, 1995Assignees: International Superconductivity Technology Center, Hokkaido Electric Power Co., Inc., Fujikura Ltd., Tokyo Gas Co., Ltd., Hitachi Cable, Ltd.Inventors: Noriyuki Tatsumi, Jiro Tsujino, Atsushi Kume, Yuh Shiohara, Shoji Tanaka, Shigenori Yuhya, Kei Kikuchi
-
Patent number: 5446017Abstract: A superconductive oxide material having an infinite layer structure and having the following formula:A.sub.p B.sub.q Cu.sub.2 O.sub.4.+-.rwherein A and B are different and each represent an element selected from lanthanoid elements and elements belonging to Groups IA, IIA and IIIA of the Periodic Table, p is between 0.9 and 1.1, q is between 0.9 and 1.1 and r is between 0 and 0.6. The oxide material has a crystal structure belonging to a tetragonal system of P4/mmm and 1-123 having the following lattice parameters:3.8.ANG..ltoreq.a.ltoreq.4.0.ANG.7.6.ANG..ltoreq.c.ltoreq.8.0.ANG.or to an orthorhombic system of Pmmm and I-47 having the following lattice parmeters:3.8.ANG..ltoreq.a.ltoreq.3.95.ANG.3.82.ANG..ltoreq.b.ltoreq.4.0.ANG.7.6.ANG..ltoreq.c.ltoreq.8.0.ANG..Type: GrantFiled: April 12, 1993Date of Patent: August 29, 1995Assignees: Central Research Institute of Electric Power Industry, Tohoku Electric Power Co., Inc., International Superconductivity Technology CenterInventors: Takeshi Sakurai, Nobuyuki Sugii, Seiji Adachi, Michiharu Ichikawa, Yuji Yaegashi, Hisao Yamauchi, Masahiko Shimada, Hirotsugu Takizawa
-
Patent number: 5444039Abstract: The oxide superconductor according to the present invention is represented by (Hg.sub.1-x Pb.sub.x)Ba.sub.2 Ca.sub.2 Cu.sub.3 O.sub..delta. (0.08.ltoreq.x.ltoreq.0.41, 7.625.ltoreq..delta..ltoreq.9.15), and has a crystal structure in which a lamination unit of (Hg, Pb)O.sub.z -BaO-CuO.sub.2 -Ca-CuO.sub.2 -Ca-CuO.sub.2 -BaO is laminated in a c-axial direction of the crystal structure (0.625.ltoreq.z.ltoreq.2.15). Further, the method of manufacturing an oxide superconductor, according to the present invention, includes the steps of: mixing material powders of HgO, PbO, BaO, CaO and CuO at a mole ratio of (Hg.sub.1-x Pb.sub.x):Ba:Ca:Cu=a:2:b:c (1.ltoreq.a.ltoreq.2.5, 2.ltoreq.b.ltoreq.3, 2.5.ltoreq.c.ltoreq.4) and compression-molding the mixture powder into a compact; and subjecting the compact to a thermal treatment at 600.degree.-750.degree. C.Type: GrantFiled: September 12, 1994Date of Patent: August 22, 1995Assignees: Tohoku Electric Power Copany, Incorporated, Sumitomo Electric Industries, Ltd., Matsushita Electric Industrial Co., Ltd., International Superconductivity Technology CenterInventors: Kazuyuki Isawa, Ayako Yamamoto, Makoto Itoh, Seiji Adachi, Hisao Yamauchi
-
Patent number: 5434125Abstract: A rare earth oxide superconducting material represented by REBa.sub.2 2Cu.sub.3 O.sub.y (RE is Y, Gd, Dy, Ito, Er or Yb), comprises oxide grains and at least one element selected from Rh and Pt, uniformly dispersed in the grain in a proportion of 0.01-5% by weight (in terms of element) based on the rare earth oxide superconducting material. The rare earth oxide superconducting material can be produced by a melt processing and gives a high critical current density even in a highly magnetic field.Type: GrantFiled: June 8, 1994Date of Patent: July 18, 1995Assignees: International Superconductivity Technology Center, NGK Insulators, Ltd., Toyota Jidosha Kabushiki KaishaInventors: Naoyuki Ogawa, Takenobu Sakai, Izumi Hirabayashi
-
Patent number: 5430010Abstract: The present invention relates to a process for preparing an oxide superconductor having a high critical current density, a uniform structure and an excellent mechanical property and thermal stability, which comprises heating raw material powders of a REBaCuO system at 1050.degree. C. or higher, cooling the material for solidification, pulverizing and mixing the solidified material to homogeneously disperse the structure of the solidified material, molding the material, optionally mixed with silver oxide or silver, into a predetermined shape, and reheating the molding to 1050.degree. C. or higher to grow a superconducting phase.Type: GrantFiled: June 8, 1993Date of Patent: July 4, 1995Assignees: International Superconductivity Technology Center, Nippon Steel CorporationInventors: Masato Murakami, Terutsugu Oyama, Hiroyuki Fujimoto, Naoki Koshizuka, Yu Shiohara, Shoji Tanaka
-
Patent number: 5421890Abstract: Disclosed is an oxide thin film producing method and apparatus for producing an oxide thin film having excellent crystallinity and purity with high productivity while correctly controlling the composition of the oxide thin film. After reducing the pressure inside a vacuum chamber to 1.times.10.sup.-9 Torr or less, a metal thin film is formed by evaporating a specified metal element and depositing vapor of the metal element on a substrate in the vacuum chamber. Then a cover member is moved upward to closely abut to a cover receiving member to thereby form an airtight chamber for enclosing the substrate airtightly in the vacuum chamber. With the degree of vacuum around the airtight chamber maintained, O.sub.2 gas is directly introduced into the airtight chamber through a gas piping to oxidize the metal thin film and thereby form an oxide thin film. At the same time, the gas inside the airtight chamber is discharged directly out of the vacuum chamber through a gas piping.Type: GrantFiled: July 29, 1993Date of Patent: June 6, 1995Assignees: International Superconductivity Technology Center, Sharp Kabushiki Kaisha, Kabushiki Kaisha Kobe Seiko ShoInventors: Ryusuke Kita, Takashi Hase, Masato Sasaki, Tadataka Morishita
-
Patent number: 5420103Abstract: A LnBaCuO-series superconducting thin film is provided over a surface of a substrate of Y.sub.2 O.sub.3 single crystal to form a composite superconductor. Ln stands for Y or a lanthanoid element. The composite superconductor has an improved interfacial diffusion.Type: GrantFiled: August 19, 1993Date of Patent: May 30, 1995Assignee: International Superconductivity Technology CenterInventors: Akira Oishi, Tadataka Morishita
-
Patent number: 5413988Abstract: An oxide superconductor thin film of Y.sub.1.+-..alpha. Ba.sub.2.+-..beta. Cu.sub.3.+-..gamma. O.sub.7-.delta. with a smooth surface having a low density of particles being generated without decreasing superconductivity is produced by the steps of applying a pulsed laser beam to the target formed of an oxide material having an apparent density of 95% or more, substantially composed of Y.sub.1.+-..alpha. Ba.sub.2.+-..beta. Cu.sub.3.+-..gamma. O.sub.7-.delta., which is obtained from a molded body of an amorphous powder by subjecting it to partial melting, followed by gradual cooling, depositing and accumulating an irradiated and evaporated oxide material of the target on a substrate.Type: GrantFiled: April 13, 1994Date of Patent: May 9, 1995Assignees: International Superconductivity Technology Center, Mitsubishi Materials CorporationInventors: Kunihiko Hayashi, Shuichi Fujino, Youichi Enomoto, Shoji Tanaka