International Superconductivity Technology Center

Matsushita Electric Industrial Co., Ltd.

Kyocera Corporation

Hitachi, Ltd.

Sumitomo Electric Industries, Limited

Sanyo Electric Co., Ltd.

The Furukawa Electric Co., Ltd.

Kabushiki Kaisha Toshiba

Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Materials Corporation

Ube Industries, Inc.

Kabushiki Kaisha Kobe Seiko Sho

Toshiba Corporation

The Tokyo Electric Power Company, Incorporated

Matsushita Electrical Industrial Co., Ltd.

Hisao Yamauchi

Shoji Tanaka

Seiji Adachi

Shinichi Koriyama

Takeshi Sakurai

Takaaki Ikemachi

Makoto Itoh

Kazuyuki Isawa

Nobuyuki Sugii

Toru Yamashita

Kazuyuki Hamada

Ayako Yamamoto

Toshiyuki Tamura

Xiao-Jing Wu

Hiroshi Kubota

Nobuo Suzuki

Takahiro Wada

Kiyoshi Yamamoto

Naoki Koshizuka

Tetsuyuki Kaneko

Michiharu Ichikawa

Shin-ichi Koriyama

Takayuki Miyatake

Koichi Kubo

Mitsunobu Wakata

Changqin Jin

Ryo Usami

Kohichi Kubo

Kiyotaka Matsuura

Roman Puzniak

Tadashi Tatsuki

In order to provide a Tl--Ba--Ca--Cu--O superconductive material which can obtain a stable superconducting state and a method of preparing the same, the oxide superconductive material is expressed in the following composition formula:

Method of preparing oxide superconductive material

The hole density of an oxide superconductor having holes as carriers is higher than the hole density to bring the highest value of the superconductivity critical temperature Tc thereof, and it can be made higher than the optimal density to bring the highest Tc value by treating the oxide superconductor with heat in an oxidizing gas atmosphere, or by replacing positive ions constituting the oxide superconductor except for copper with ions of a low valence number. Accordingly, it is possible to substantially reduce the rate of decrease of the critical current density owing to an applied magnetic field when the magnetic field is applied parallel to the crystal c axis, and to allow a current conductor produced by using the oxide superconductor to have high critical current density.

Oxide superconductor and process of producing the same

The present invention is an oxide superconductor containing alkaline earth metal M (where M is at least one element of Ba, Sr, and Ca) and having a crystalline structure in which a portion based on two rock-salt structures including the alkaline earth metal M, oxygen, and chlorine, and a 2n-1 piece of infinite layer structure portion are alternately layered on each other, said 2n-1 piece of infinite layer structure portion having an atom layer including copper atoms and oxygen atoms in a ratio of 1 to 2 and of an atom layer including only M atoms layered on each other (where n is an integer of 1 or more and where copper atoms and oxygen atom are contained in a ratio of 1 to 2 if n is 1).

Rock-salt/infinite layer chlorine-containing oxide superconductor and

The present invention provides an oxide superconductor which is expressed in the composition formula

Oxide superconductor and method for manufacturing the same

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.

(Hg Cu)Bg.sub.2 Ca.sub.2 Cu.sub.3 Oy oxide superconductor and method of

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.

1-2-4 copper oxide superconductor, a process for its production, and a

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 secbutoxy 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.

Copper oxide superconductor, a process for its production, and a copper

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.

(Hg,Cu)Ba.sub.2 Ca.sub.2 Cu.sub.3 O.sub.y oxide superconductor and

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.

High temperature oxide superconductor

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.

Method of manufacturing an oxide superconductor thin film

Disclosed is a boride material for electronic elements, which is represented by a chemical formula of A.sub.1-x E.sub.x B.sub.12 (where A is Zr of Hf, E is Sc or Y, and 0.1.ltoreq.x.ltoreq.0.9) and the crystal system of which is a cubic one at a temperature not lower than its phase transition temperature and is a hexagonal one at a temperature not higher than its phase transition temperature. The boride material is prepared by mixing oxide powders or sulfate powders of the constitutive elements A and E and a boron powder followed by shaping the powder mixture and then sintering the shaped body.

Boride materials for electronic elements and method of preparing the same

Oxide superconductor and manufacturing method thereof via HIP and

An oxide superconductor comprises a composition represented by the composition formula: (Nd.sub.x --Ce.sub.y --L.sub.z).sub.2 CuO.sub.4-d (wherein L is an element selected from Ca and Mg, and x+y+z=1). The compositions of Nd, Ce and L of the oxide superconductor corresponds to a point falling inside an area of Nd--Ce--L ternary diagram surrounded by straight lines (A-B), (B-C), (C-D) and (D-A) connecting point (A) with point (B), point (B) with point (C), point (C) with point (D) and point (D) with point (A), respectively, the points (A), (B), (C) and (D) being points (x=1, y=0, z=0), (x=0.4, y=0.6, z=0), (x=0.4, y=0.3, z=0.3) and (x=0.1, y=0, z=0.9), respectively, in the Nd--Ce--L ternary diagram. Above-described Nd--Ce--L--Cu--O oxides can exhibit superconductivity within a wide range of composition when heat-treated in an atmosphere of nitrogen.

N-type oxide superconductor represented by the formula (Nd.sub.x

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Hisao Yamauchi