Abstract: A boron nitride system starts with an hBN material and yields a directly converted sintered cBN body having a high heat conductivity within the range of at least 4 W/cm..degree.C. to about 6.2 W/cm..degree.C. For this purpose the hBN starting material of the system has diffused therein an additive of an alkaline earth metal or alkali metal in an amount of from 0.6 mol % to 1.3 mol %. This starting material is directly converted into the cBN at a sintering temperature of at least 1350.degree. C. under a thermodynamically stabilized condition for the cBN, which contains cBN within the range of 99.9 to 99.3 wt. % of the sintered body and a metal remainder from the additive of the starting material within the range of 0.1 to 0.7 wt. % of the sintered body, except for minute naturally occurring components.

Abstract: A process for producing a sintered ceramic wire, particularly a superconducting wire, by the steps of filling a metal pipe with a material powder of ceramic, wire drawing the metal pipe filled with the material powder by means of roller dies and then subjecting a composite of the metal pipe and the material powder to a heating operation to sinter the ceramic powder.

Abstract: 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.

Abstract: This invention relates to new superconducting material having a composition represented by the general formula:A.sub.u B.sub.v C.sub.w D.sub.x E.sub.

Abstract: A superconducting material and a process for producing a superconducting material comprising a compound oxide represented by the general formula:(Ba, .gamma.).sub.x (.alpha.,.beta.).sub.1 -.sub.x .epsilon..sub.y Cu.sub.1-y O.sub.3 -zin which".gamma." represents an element of the IIa group of the periodic table except Ba, an atomic ratio of .gamma. to Ba, being selected in a range between 1% and 90%,".alpha.represents Y or La,".beta." represents an element of the IIIa group of the periodic table but is different from .alpha., an atomic ratio of .beta. to .alpha. being selected in a range between 1 and 90%,".epsilon." represents a metal element of the IIIb group of the periodic table,x, y and z are numbers each satisfies ranges of O.ltoreq.x.ltoreq.1, O.ltoreq.y.ltoreq.1, and O.ltoreq.z.ltoreq.1 respectively, andthe expression of (Ba, .gamma.) and (.alpha., .beta.) mean that the respective elements occupy predetermined sites in a crystal in a predetermined proportion.

Abstract: An outer surface of a superconducting film of compound oxide such as YBa.sub.2 Cu.sub.3 O.sub.7-.delta. is protected with a protective layer which is composed of any one of (i) oxide of metal such as MgO, CaO, SrO etc, (ii) carbide such as SiC, or (iii) nitride such as BN.

Abstract: Improvement in a superconducting thin film of compound oxide represented by the formula: LnBa.sub.2 Cu.sub.3 O.sub.7- .delta. (Ln is lanthanide) or (La.sub.1-x .alpha..sub.x).sub.2 CuO.sub.4 (.alpha. is Ba or Sr) deposited on a substrate or core made of MgO, SrTiO.sub.3 or ZrO.sub.2 by physical vapor deposition technique, the surface roughness R.sub.max (datum length=1,000 .mu.m) of the superconducting thin film being less than 0.2 .mu.m.

Abstract: A now superconducting material comprising a compound oxide represented by the general formula:(Ba, Ca).sub.x (.alpha., Dy).sub.1-x Tl.sub.y Cu.sub.1-y O.sub.3-zwherein".alpha." represents Y or La;the atomic ratio of Ca to Ba is between 1% and 90%;the atomic ratio of Dy to .alpha. is between 1% and 90%;x, y and z are within the ranges of 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1, and 0.ltoreq.z<1 respectively; andthe expression of (Ba, Ca) and (.alpha., Dy) mean that the respective elements occupy predetermined sites in a crystal in a predetermined proportion.

Abstract: A tunnel junction type superconducting device includes a pair of superconductor electrodes formed of compound oxide superconductor material, and a metal layer of a high electric conductivity formed between the pair of superconductor electrodes so as to maintain the pair of superconductor electrodes separate from each other. The pair of superconductor electrodes is separated from each other by a distance within a range of 3 nm to 70 nm by action of the metal layer.

Abstract: A metal electrode formed on an oxide superconductor for electric connection to the oxide superconductor, includes a first layer of Ag in direct contact with the oxide superconductor, and a second layer formed on the first layer. The second layer is formed of noble metal excluding Ag. The metal electrode can be formed by forming a first layer of Ag to cover a whole surface of the oxide superconductor layer, and forming a second layer of noble metal excluding Ag, to cover a whole surface of the first layer, thereby to form a double metal layer, and patterning the double metal layer so as to form a metal electrode composed of the double metal layer.

Abstract: A process for depositing a superconducting thin film composed mainly of compound oxide such as LnBa.sub.2 Cu.sub.3 O.sub.7-.delta. (Ln is lanthanide) or (La.sub.1-x .alpha..sub.x).sub.2 CuO.sub.4 (.alpha. is Ba or Sr) on a substrate such as MgO, SrTiO.sub.3 or silicon by sputtering technique, characterized in that a negative bias is applied to the substrate during the sputtering stage without heating the substrate.

Abstract: A superconducting material composed mainly of compound oxide having a composition represented by the general formula:Tl.sub.x Ca.sub.y BaCu.sub.z O.sub.pin which "x", "y" and "z" are numbers each satisfies 0.5.ltoreq.x.ltoreq.3.0, 0.5.ltoreq.y.ltoreq.3.0, and 0.9.ltoreq.z.ltoreq.4.0 respectively.

Abstract: A semiconductor substrate having a silicon substrate and a superconducting thin film layer composed of compound oxide such as Ln.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-.delta. (Ln is lanthanide) and stratified on the silicon substrate, characterized in that an intermediate semiconductor layer composed of compound semiconductor material such as GaAs is interposed between the silicon substrate and the superconducting thin film layer.

Abstract: A method for preparing a thin film of superconductor on a substrate by sputtering. A target prepared from an oxide containing Ba, Y, and Cu in atomic ratios Cu/Y of 2.5 to 3.5 and Ba/Y of 1.8 to 2.2 is employed to form by sputtering a superconducting thin film on a substrate at a temperature of 600.degree. to 800.degree. C. in an atmosphere having total gas pressure of 1.times.10.sup.-2 to 5.times.10.sup.-2 Torr. and containing Ar and O.sub.2 with an O.sub.2 content of 5 to 80 vol. %. The thin film thus formed is subjected to heat treatment at a temperature of 600.degree. to 930.degree. C. for 1 to 30 hours. The thin film after the heat treatment is cooled at a rate not more than 4.degree. C./min. The film forming surface of the substrate is chosen from the (100) surface or the (110) surface of a single crystal substrate which is lattice-matched with the (100) surface or the (110) surface of crystalline Y.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-n, where n represents a number in the range 0.ltoreq.n<1.

Abstract: Improvement in heat-treatment of a superconducting thin film of thallium type compound oxide deposited on a substrate by PVD or CVD. In the invention, the heat-treatment is effected at a temperature between 880.degree. C. and 920.degree. C. for a predetermined time duration under such a condition that the partial pressure of thallium oxide becomes higher than the saturated vapour pressure of thallium oxide at said temperature.

Abstract: A now superconducting material comprising a compound oxide represented by the general formula:(Sr,.gamma.).sub.x (La,.delta.).sub.1-x .epsilon..sub.y Cu.sub.1-y O.sub.3-zin which".gamma." represents an element of IIa group of the periodic table except Sr, an atomic ratio of .gamma. to Sr being selected in a range between 1% and 90%,".delta." represents an element of IIIa group of the periodic except La, an atomic ratio of .delta. to La is selected in a range between 1% and 90%,".epsilon." represents a metal element of Vb group of the periodic table, x, y and z are numbers each satisfies ranges of 0.ltoreq.x.ltoreq.1,0.ltoreq.y.ltoreq.1, and 0.ltoreq.z.ltoreq.1 respectively, and the expression of (Sr,.gamma.) and (La,.delta.) mean that the respective elements position predetermined sites in a crystal in a predetermined proportion.

Abstract: A semiconductor substrate such as silicon single crystal having a thin film of a superconducting material composed of a compound oxide whose critical temperature is higher than 30 K such as Ln.sub.1 Ba.sub.2 Cu.sub.3 O.sub.7-.delta. (Ln is Y or lanthanide), characterized in that a buffer layer composed of ZrO.sub.2, MgO containing or not containing metal element such as Ag is interposed between the semiconductor substrate and the superconducting thin film.

Abstract: A new high Tc superconducting compound oxide material represented by the general formula:AuBvCwCuxOyin which"A" is selected from the group consisting of magnesium(Mg), calcium(Ca), strontium(Sr) and barium(Ba);"B" is selected from the group consisting of yttrium(Y), lanthanum(La), and lanthanide elements;"C" is selected from the group consisting of vanadium (V), tantalum(Ta), indium(In), and thallium(Tl), and ##EQU1##

Abstract: A superconducting composite comprising a compound oxide type superconductor and an outer metal pipe on which said superconductor is supported, characterized in that (i) said outer metal pipe is made of at least one of metals selected from a group comprising gold, silver and platinum metals and their alloys or (ii) an intermediate layer made of these precious metals is interposed between the compound oxide and the metal pipe.The composite may be in a form of a solid pipe or a hollow pipe having a superconducting thin layer deposited on an inner surface of the metal pipe.

Abstract: An improvement in a process for manufacturing a superconductor, characterized by irradiating a material composed of compound oxide by one of ion beams selected from oxygen ion beam, inert gas ion beams and an ion beam consisting of a mixture of oxygen gas and inert gas to convert said material into a superconductor. When a focused ion beam is directed onto desired areas on said film layer, the areas irradiated by the ion beam are converted to a superconductor in a form of a superconducting circuit.