USH1683H - Superconducting material - Google Patents
Superconducting material Download PDFInfo
- Publication number
- USH1683H USH1683H US08/474,797 US47479795A USH1683H US H1683 H USH1683 H US H1683H US 47479795 A US47479795 A US 47479795A US H1683 H USH1683 H US H1683H
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- US
- United States
- Prior art keywords
- superconducting
- element selected
- yttrium
- copper
- barium
- Prior art date
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- Abandoned
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- 239000000463 material Substances 0.000 title claims abstract description 42
- 239000011734 sodium Substances 0.000 claims abstract description 9
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims abstract description 6
- 229910052708 sodium Inorganic materials 0.000 claims abstract description 6
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 5
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 5
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 5
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 5
- 239000011591 potassium Substances 0.000 claims abstract description 5
- 229910010293 ceramic material Inorganic materials 0.000 claims description 15
- 239000011575 calcium Substances 0.000 claims description 12
- 239000011777 magnesium Substances 0.000 claims description 12
- 229910052783 alkali metal Inorganic materials 0.000 claims description 11
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 claims description 8
- 229910052727 yttrium Inorganic materials 0.000 claims description 8
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 claims description 8
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 7
- 229910052790 beryllium Inorganic materials 0.000 claims description 7
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 claims description 7
- 229910052749 magnesium Inorganic materials 0.000 claims description 7
- 239000005751 Copper oxide Substances 0.000 claims description 6
- 229910052788 barium Inorganic materials 0.000 claims description 6
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 6
- 229910000431 copper oxide Inorganic materials 0.000 claims description 6
- 229910052736 halogen Inorganic materials 0.000 claims description 6
- 150000002367 halogens Chemical class 0.000 claims description 6
- 229910052712 strontium Inorganic materials 0.000 claims description 6
- 229910052747 lanthanoid Inorganic materials 0.000 claims description 5
- 150000002602 lanthanoids Chemical class 0.000 claims description 5
- 229910052705 radium Inorganic materials 0.000 claims description 5
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims description 4
- 229910052692 Dysprosium Inorganic materials 0.000 claims description 4
- 229910052691 Erbium Inorganic materials 0.000 claims description 4
- 229910052693 Europium Inorganic materials 0.000 claims description 4
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 4
- 229910052765 Lutetium Inorganic materials 0.000 claims description 4
- 229910052771 Terbium Inorganic materials 0.000 claims description 4
- 229910052775 Thulium Inorganic materials 0.000 claims description 4
- 229910052769 Ytterbium Inorganic materials 0.000 claims description 4
- 229910052791 calcium Inorganic materials 0.000 claims description 4
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 claims description 4
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 claims description 4
- OGPBJKLSAFTDLK-UHFFFAOYSA-N europium atom Chemical compound [Eu] OGPBJKLSAFTDLK-UHFFFAOYSA-N 0.000 claims description 4
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 claims description 4
- OHSVLFRHMCKCQY-UHFFFAOYSA-N lutetium atom Chemical compound [Lu] OHSVLFRHMCKCQY-UHFFFAOYSA-N 0.000 claims description 4
- HCWPIIXVSYCSAN-UHFFFAOYSA-N radium atom Chemical compound [Ra] HCWPIIXVSYCSAN-UHFFFAOYSA-N 0.000 claims description 4
- 229910052706 scandium Inorganic materials 0.000 claims description 4
- SIXSYDAISGFNSX-UHFFFAOYSA-N scandium atom Chemical compound [Sc] SIXSYDAISGFNSX-UHFFFAOYSA-N 0.000 claims description 4
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 claims description 4
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 claims description 4
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 claims description 4
- 229960004643 cupric oxide Drugs 0.000 claims 5
- 229910052689 Holmium Inorganic materials 0.000 claims 3
- 150000001340 alkali metals Chemical class 0.000 claims 3
- KJZYNXUDTRRSPN-UHFFFAOYSA-N holmium atom Chemical compound [Ho] KJZYNXUDTRRSPN-UHFFFAOYSA-N 0.000 claims 3
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims 1
- 229910052731 fluorine Inorganic materials 0.000 claims 1
- 239000011737 fluorine Substances 0.000 claims 1
- 239000000203 mixture Substances 0.000 abstract description 9
- 239000010949 copper Substances 0.000 description 14
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 11
- 239000002245 particle Substances 0.000 description 10
- 239000012535 impurity Substances 0.000 description 8
- 150000001875 compounds Chemical class 0.000 description 7
- 238000010304 firing Methods 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 239000007858 starting material Substances 0.000 description 7
- 230000000737 periodic effect Effects 0.000 description 6
- 239000000843 powder Substances 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 5
- 239000000919 ceramic Substances 0.000 description 5
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 229910052760 oxygen Inorganic materials 0.000 description 5
- 239000001301 oxygen Substances 0.000 description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 230000001590 oxidative effect Effects 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 3
- 229910052796 boron Inorganic materials 0.000 description 3
- 229910002090 carbon oxide Inorganic materials 0.000 description 3
- 229910052802 copper Inorganic materials 0.000 description 3
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 239000005749 Copper compound Substances 0.000 description 2
- 150000001342 alkaline earth metals Chemical class 0.000 description 2
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 description 2
- 150000001553 barium compounds Chemical class 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 239000002775 capsule Substances 0.000 description 2
- 150000001880 copper compounds Chemical class 0.000 description 2
- 239000008214 highly purified water Substances 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- 229910052574 oxide ceramic Inorganic materials 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 239000000758 substrate Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical class [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229910002480 Cu-O Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- 150000002500 ions Chemical group 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- JCXJVPUVTGWSNB-UHFFFAOYSA-N nitrogen dioxide Inorganic materials O=[N]=O JCXJVPUVTGWSNB-UHFFFAOYSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000011224 oxide ceramic Substances 0.000 description 1
- UZLYXNNZYFBAQO-UHFFFAOYSA-N oxygen(2-);ytterbium(3+) Chemical compound [O-2].[O-2].[O-2].[Yb+3].[Yb+3] UZLYXNNZYFBAQO-UHFFFAOYSA-N 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 150000003438 strontium compounds Chemical class 0.000 description 1
- 238000009210 therapy by ultrasound Methods 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910003454 ytterbium oxide Inorganic materials 0.000 description 1
- 229940075624 ytterbium oxide Drugs 0.000 description 1
- -1 yttrium compound Chemical class 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N60/00—Superconducting devices
- H10N60/80—Constructional details
- H10N60/85—Superconducting active materials
- H10N60/855—Ceramic superconductors
- H10N60/857—Ceramic superconductors comprising copper oxide
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/45—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on copper oxide or solid solutions thereof with other oxides
- C04B35/4504—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on copper oxide or solid solutions thereof with other oxides containing rare earth oxides
Definitions
- the present invention relates to an oxide ceramic superconducting material, and more particularly to a composition wherein the temperature of a superconducting material at which electrical resistance becomes zero (which is referred to as Tco hereinafter) approaches a room temperature as much as possible.
- a metallic composition including elements such as mercury and lead, alloys such as NbN, Nb 3 Ge, Nb 3 Ga, or three-element compounds such as Nb 3 (Al 0 .8 Ge 0 .2) are used as superconducting materials.
- the onset of the superconducting critical temperature (which is referred to as Tc hereinafter) is as low as 25° K.
- the inventor of the present invention has discovered, during efforts to improve the Tco and Tc of the superconducting ceramic materials, that these impurities collect at the boundaries of the ceramic particles and act as a barrier between the particles to which they adhere, so that they interfere with the electrical conductivity. In such conditions, it is not possible to increase the current density, and the Tco is lower than expected.
- An object of the present invention is to provide, with due consideration to the drawbacks of such conventional materials, a superconducting material, utilizing new materials of high purity, which exhibits superconductivity at high temperatures, so that the Tc onset occurs between 80° K and 124° K.
- a further object of the present invention is to provide a lower density of impurities contained throughout the superconducting ceramic material represented by the expression (A 1-x B x ) y Cu z O w .
- a superconducting composition is provided to essentially consist of a superconducting material and no more than 0.2% by weight of Li(lithium), Na(sodium), and K(potassium) mixed into the superconducting material.
- FIG. 1 is a graph showing the characteristics of the superconducting material made according to the present invention.
- a ceramic superconducting material is made to essentially consist copper, oxygen and at least one element selected from the group of Groups 11a and 111a of the Periodic Table.
- A is one element selected from the group of the yttrium group and other lanthanides.
- the yttrium group is defined in "Physic and Chemistry Dictionary" (published Apr.
- B is at least one element selected from the group of Ra(radium), Ba(barium), Sr(strontium), Ca(calcium), Mg(magnesium), and Be(beryllium).
- composition of the present invention contains copper in a layered configuration, with one layer within one unit cell, or in a symmetric two-layer structure, and is based on a model in which superconductivity is obtained from the orbit of the furthest exterior nucleus electron.
- raw materials of 99.99% (4N) purity or higher are used rather than the conventionally-used 99(2N) to 99. 95% purity as a starting material.
- an oxygen atmosphere of a purity in excess of 4N is used rather than air for oxidation, and the material is fired in 5N oxygen and 5N argon, or under vacuum for reduction.
- the crystalline grain size can be made larger, and in turn, a structure can be obtained to which the barrier at the crystal boundaries is caused to further disappear. As a result, an even higher Tco is obtained. In this case, ideally there would be a single crystalline structure in the nucleus with no defects.
- the oxide or carbon oxides as the starting materials are mixed, compressed or compacted once, and an (A 1-x B x ) y Cu z O w type of structure is created from the oxide or carbon oxide.
- this material is ground to form a fine powder, once again compressed or compacted into tablet form, and fired.
- the new type of superconducting ceramic material of the present invention can be formed by an extremely simple process.
- oxide or carbon oxide materials of 5N or 6N purity are used as the starting materials, finely ground in a ball mill, and mixed.
- the respective values for x,y, z, and w in the expression (A 1-x B x ) y Cu z O w can be optionally varied and controlled stoichiometrically.
- the present invention has made it possible to produce ceramic superconducting bodies which have been completely unattainable inthe past.
- the respective starting material compounds are substantially the same as the final compound, specifically the compounds including the materials indicated by the expression (A 1-x B x ) y Cu z O w as a result of finely grinding the material after pre-firing.
- a plurality of elements from Groups 11a and 111a of the Periodic Table are blended together in these end material compounds because the copper is more easily obtained in a layered configuration within the molecular configuration. In this way, the impurities which tend to segregate at the particle boundaries of the final compound are removed. In other materials, the respective particles tend to more easily fuse with the adjacent particles. Observation with an electron microscope ( ⁇ 40,000) shows that the spherical and granular particles are packed together in the third example with larger adjacent apertures. On the other hand, in the first example of the present invention, there is a sufficiently high degree of denseness in the packing and therefore only a few apertures are seen in the spheres.
- the respective polycrystalline particles are clearly seen to be mutually adhering in a face to face relationship.
- the Tc onset and Tco can be presumed to be at a higher temperature in the present invention because the alkali metal elements, halogen elements, carbon, and nitrogen have been removed.
- the mechanism of the superconductivity of the superconducting ceramic materials which exhibit the molecular structure of the present invention is presumed to be related to the fact that the copper oxide material has a laminar structure, and this laminar structure has one layer or two layers in one unit cell. The superconductivity is obtained through carriers within this layer.
- the present invention has succeeded for the first time in the world in enlarging the mutual surfaces of the particles and obtaining intimate contact between them by eliminating or reducing the alkali metal elements, halogen elements, carbon, and nitrogen.
- the embodiments of the present invention are made in tablet form. However, it is possible to prepare a thin film superconducting ceramic material without the tablet step, dissolving the powder in a solvent after a pre-firing or full firing, coating a substrate or the like with that solution and firing the coated substrate in an oxidizing atmosphere, followed by firing in a reducing atmosphere.
- A is one or more elements of Group IIIa of the Periodic Table, e.g., the rare earth elements
- B is one or more elements of Group IIa of the Periodic Table, e.g., the alkaline earth metals including beryllium and magnesium
- x 0 to 1
- y 2.0 to 4.0, preferably
- superconducting ceramics for use in accordance with the present invention may be prepared consistent with the stoichiometric formulae (A 1-x B x ) y Cu z O w , where A is one or more elements of Group Vb of the Periodic Table such as Bi, Sb, and As.
- the Tconset and Tco of the composition Bi 4 Sr 4 Ca 2 Cu4O x are 110° K and 79° K, respectively.
- the value of x in the above formulae is estimeated to be 6 to 10, for example about 8.1.
- the stoichiometric formulae mentioned above can be determined for example by X-ray diffracton.
- Example 1 of the present invention Y was used as A and Ba as B in the general expression.
- This process is referred to as the pre-firing process.
- this material was ground and blended in a mortar to an average particle radius of 10 ⁇ m or less.
- This blended powder was sealingly inserted into a capsule and formed into tablets by compressing at a load of 50 kg/cm 2 .
- the methods may also be adopted in a hot press system where the tablet is heated while it is being pressed, or in which an electric current is applied to the tablet, so that a light elecrtric current flows through the tablet while the tablet is being heated.
- an oxidizing process was performed at between 500° C. and 1000° C., for example at 900° C., in an oxidizing atmosphere such as an atmosphere of highly purified oxygen, and full firing was carried out for 10 to 50 hours, for example, 15 hours.
- this sample material was heated in a low oxygen O 2 -Ar mixture (with other impurities at 10 ppm or less) for 3 to 30 hours at 600° C. to 1100° C., for example, and for 20 hours at 800° C., for reduction, resulting in a new structure which was observed clearly.
- O 2 -Ar mixture with other impurities at 10 ppm or less
- the relationship between the specific resistance and temperature was determined.
- the highest temperature obtained for the Tc onset was observed to be 114° K, while the Tco was observed to be 103° K.
- the amount of impurities present was measured by means of a Secondary Ion Mass Spectrometer (SIMS).
- SIMS Secondary Ion Mass Spectrometer
- the amount of nitrogen and carbon dioxide were 0.1% or less by weight, specifically measured at only 0.01% by weight.
- the halogen elements detected were 0.1% or less by weight, specifically detected at only 0.001% by weight.
- the alkali metal elements were 0.2% or less by weight, specifically detected at only 0.001% by weight.
- FIG. 1 shows the temperature versus specific resistance characteristics of the superconducting material of the present invention which was obtained n this example.
- the Tc onset obtained was 119° K, and Tco 107° K in this example.
- This example was made on the basis of a conventional method for comparison.
- Example 1 the starting materials were 3N in purity.
- the material was blended in the form of fine powders, but only a simple washing with city water being performed rather than ultrasonic washing with highly purified water. Other manufacturing conditions remained the same.
- the Tc in this case was only 92° K and Tco only 74° K.
- the results of analyses for impurities run on the formed tablets gave 0.3% by weight for sodium in the alkali metal elements, and 0.5% by weight for carbon and nitrogen.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Abstract
A superconducting composition is provided to essentially consist of a superconducting material and Li(lithium), Na(sodium), and K(potassium) mixed in an amount up to 0.2% by weight of of the composition into the superconducting material.
Description
This is a Continuation application of Ser. No. 08/286,917, filed Aug. 8, 1994 abandoned; which is a Continuation of Ser. No. 08/060,714, filed May 13, 1993, abandoned; which itself is a continuation of Ser. No. 07/593,656, filed Oct. 3, 1990, abandoned; which is a division of Ser. No. 07/550,793, filed Jul. 6, 1990, abandoned; which is a continuation of Ser. No. 07/174,420, filed Mar. 25, 1988, abandoned.
1. Field of the Invention
The present invention relates to an oxide ceramic superconducting material, and more particularly to a composition wherein the temperature of a superconducting material at which electrical resistance becomes zero (which is referred to as Tco hereinafter) approaches a room temperature as much as possible.
2. Background of the Invention
Conventionally, a metallic composition including elements such as mercury and lead, alloys such as NbN, Nb3 Ge, Nb3 Ga, or three-element compounds such as Nb3 (Al0.8 Ge0.2) are used as superconducting materials. However, the onset of the superconducting critical temperature (which is referred to as Tc hereinafter) is as low as 25° K.
On the other hand, in recent years, superconducting ceramic materials have been attracting a lot of attention. The Zurich Research Laboratory of IBM first reported these materials in the form of the Ba-La-Cu-O (balacuo) type of high-temperature oxide superconducting bodies. In addition, the cupric oxide--lanthanum--strontium (LSCO) type is also known. These materials are known in the form (A1-x Bx)y CuOz, where x=0.01 to 0.3, y=1.3 to 2.2, z=2.0 to 4.0. However, the Tc onset, that is the temperature at which superconducting begins for this material is no more than 30° K.
However, there is the possibility that the superconductivity of these oxide ceramic materials is associated with a perbuscite-type structure. Up to now, no consideration has been given to impuirities, with the attitude taken that if the starting raw materials are 99% pure, this is adequate. For this reason, absolutely no consideration has been given to impurities, especially alkali metal elements, halogen elements, nitrogen and carbon, which are mixed into the synthesized superconducting material.
The inventor of the present invention has discovered, during efforts to improve the Tco and Tc of the superconducting ceramic materials, that these impurities collect at the boundaries of the ceramic particles and act as a barrier between the particles to which they adhere, so that they interfere with the electrical conductivity. In such conditions, it is not possible to increase the current density, and the Tco is lower than expected.
Therefore, it is strongly desired that steps taken to increase the Tco, preferably to the temperature of liquid nitrogen (77° K) or greater.
An object of the present invention is to provide, with due consideration to the drawbacks of such conventional materials, a superconducting material, utilizing new materials of high purity, which exhibits superconductivity at high temperatures, so that the Tc onset occurs between 80° K and 124° K.
A further object of the present invention is to provide a lower density of impurities contained throughout the superconducting ceramic material represented by the expression (A1-x Bx)y Cuz Ow.
Accordingly, a superconducting composition is provided to essentially consist of a superconducting material and no more than 0.2% by weight of Li(lithium), Na(sodium), and K(potassium) mixed into the superconducting material.
These and other objects, features, and advantages of the present invention will become more apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a graph showing the characteristics of the superconducting material made according to the present invention.
To satisfy these objects of the present invention, a ceramic superconducting material is made to essentially consist copper, oxygen and at least one element selected from the group of Groups 11a and 111a of the Periodic Table. One example of a general formula representing the molecule of this ceramic superconducting material is (A1-x Bx)y Cuz Ow, where x=0 to 1, y=2.0 to 4.0 or preferably 2.5 to 3.5, z=1.0 to 4.0 or preferably 1.5 to 3.5, and w=4.0 to 10.0 or preferably 6 to 8. A is one element selected from the group of the yttrium group and other lanthanides. The yttrium group is defined in "Physic and Chemistry Dictionary" (published Apr. 1, 1963, Iwanami Shoten) as the group includes Y(yttrium), Gd(gadolinium), Yb(ytterbium), Eu(europium), Tb(terbium), Dy(dysprosium), Ho(holnium), Er(erbium), Tm(thulium), Lu(lutetium), Sc(scandium), and other lanthanides. Also, B is at least one element selected from the group of Ra(radium), Ba(barium), Sr(strontium), Ca(calcium), Mg(magnesium), and Be(beryllium).
The composition of the present invention contains copper in a layered configuration, with one layer within one unit cell, or in a symmetric two-layer structure, and is based on a model in which superconductivity is obtained from the orbit of the furthest exterior nucleus electron.
For this reason, raw materials of 99.99% (4N) purity or higher are used rather than the conventionally-used 99(2N) to 99. 95% purity as a starting material. Then, an oxygen atmosphere of a purity in excess of 4N is used rather than air for oxidation, and the material is fired in 5N oxygen and 5N argon, or under vacuum for reduction.
In this way, in a polycrystalline ceramic material, the crystalline grain size can be made larger, and in turn, a structure can be obtained to which the barrier at the crystal boundaries is caused to further disappear. As a result, an even higher Tco is obtained. In this case, ideally there would be a single crystalline structure in the nucleus with no defects.
In the present invention, the oxide or carbon oxides as the starting materials are mixed, compressed or compacted once, and an (A1-x Bx)y Cuz O w type of structure is created from the oxide or carbon oxide.
Then this material is ground to form a fine powder, once again compressed or compacted into tablet form, and fired.
The new type of superconducting ceramic material of the present invention can be formed by an extremely simple process. In particular, oxide or carbon oxide materials of 5N or 6N purity are used as the starting materials, finely ground in a ball mill, and mixed. When this is completed, the respective values for x,y, z, and w in the expression (A1-x Bx)y Cuz Ow can be optionally varied and controlled stoichiometrically.
The present invention has made it possible to produce ceramic superconducting bodies which have been completely unattainable inthe past.
In the present invention, the respective starting material compounds are substantially the same as the final compound, specifically the compounds including the materials indicated by the expression (A1-x Bx)y Cuz Ow as a result of finely grinding the material after pre-firing.
Further, a plurality of elements from Groups 11a and 111a of the Periodic Table are blended together in these end material compounds because the copper is more easily obtained in a layered configuration within the molecular configuration. In this way, the impurities which tend to segregate at the particle boundaries of the final compound are removed. In other materials, the respective particles tend to more easily fuse with the adjacent particles. Observation with an electron microscope (×40,000) shows that the spherical and granular particles are packed together in the third example with larger adjacent apertures. On the other hand, in the first example of the present invention, there is a sufficiently high degree of denseness in the packing and therefore only a few apertures are seen in the spheres. The respective polycrystalline particles are clearly seen to be mutually adhering in a face to face relationship. Specifically, the Tc onset and Tco can be presumed to be at a higher temperature in the present invention because the alkali metal elements, halogen elements, carbon, and nitrogen have been removed.
Also, the mechanism of the superconductivity of the superconducting ceramic materials which exhibit the molecular structure of the present invention is presumed to be related to the fact that the copper oxide material has a laminar structure, and this laminar structure has one layer or two layers in one unit cell. The superconductivity is obtained through carriers within this layer.
If the contact area at the boundaries of the layers and the adjacent particles within the molecule is small, this is an extremely large obstacle to providing an increase in the maximum current flow obtained, and an increase in the Tco. The present invention has succeeded for the first time in the world in enlarging the mutual surfaces of the particles and obtaining intimate contact between them by eliminating or reducing the alkali metal elements, halogen elements, carbon, and nitrogen.
The embodiments of the present invention are made in tablet form. However, it is possible to prepare a thin film superconducting ceramic material without the tablet step, dissolving the powder in a solvent after a pre-firing or full firing, coating a substrate or the like with that solution and firing the coated substrate in an oxidizing atmosphere, followed by firing in a reducing atmosphere.
The superconducting ceramic material for use in accordance with the present invention also may be prepared consistent with the stoichiometric formulae (A1-x Bx)y Cuz Ow, where A is one or more elements of Group IIIa of the Periodic Table, e.g., the rare earth elements, B is one or more elements of Group IIa of the Periodic Table, e.g., the alkaline earth metals including beryllium and magnesium, and x=0 to 1, y=2.0 to 4.0, preferably 2.5 to 3.5; z=1.0 to 4.0, preferably 1.5 to 3.5; and w=4.0 to 10.0, preferably 6.0 to 8.0. Also, superconducting ceramics for use in accordance with the present invention may be prepared consistent with the stoichiometric formulae (A1-x Bx)y Cuz Ow, where A is one or more elements of Group Vb of the Periodic Table such as Bi, Sb, and As. B i s one or more elements of Group IIa of the Periodic Table, e.g., the alkaline earth metals including beryllium and magnesium, and x=0 to 1; y=2.0 to 4. 0, preferably 2.5 to 3.5; z=1.0 to 4.0, preferably 1.5 to 3.5; and w=4.0 to 10.0, preferably 6.0 to 8.0. One example of the former formulae is YBa2 Cu3 Ox (x=6 to 8), and examples of the latter formulae are BiSrCaCu2 Ox and Bi4 Sr3 Ca3 Cu4 Ox ain addition, the composition Bi4 (Sry Ca2)Cu4 Ox is possible for such purposes and its Tc is 40 to 60 when the value of y is about 1.5. The Tconset and Tco of the composition Bi4 Sr4 Ca2 Cu4Ox are 110° K and 79° K, respectively. The value of x in the above formulae is estimeated to be 6 to 10, for example about 8.1.
The superconducting material is also generally represented as (A1-x Bx)y Cuz Ow wherein x=0 to 1; y=2.0 to 4.0; w=4.0 to 10.0; and A is at least one element selected from the group of Ga, Zr, Nb, and Ge, and B is at least one element selected from the group of alkali earth metals. Specifically, desirable ranges are; x=0.1 to 1;y=2.5 to 3.5; z=1.5 to 3.5; w=7.0 to 8.0.
The stoichiometric formulae mentioned above can be determined for example by X-ray diffracton.
In Example 1 of the present invention, Y was used as A and Ba as B in the general expression.
As starting materials, yttrium oxide (Y2O3) was used as the yttrium compound, barium carbonate (BaCO3) as the barium compound, and copper oxide (CuO) as the copper compound. These were used in the form of fine powders with a purity of 99.99% or higher. The proportions were selected, so that x=0.33 (A:B=2:1), y=3, z=3, and w=6 to 8. Ba for the B and B' and Ca were selected in a 1:1 ratio.
These materials were thoroughly blended in a mortar, washed well with highly purified water (specific resistance 18M ohms or greater) using an ultrasonic treatment, and then dried. In this way, alkali metal elements such as Li(lithium), Na(sodium), or K(potassium) and the like could be adequately washed out in this process. It was therefore possible to reduce the concentration of impurities throughout the finished material to 0.2% by weight, or preferably 0.005% by weight or less. This blended powder was then inserted into a capsule and formed into tablets (10 mm diameter×3 mm) at a load of 30 kg/cm2. The tablets were then heated and oxidized in an oxidizing atmosphere, for example, in air at 500° C. to 1000° C., and, for example, 700° C. for 8 hours.
This process is referred to as the pre-firing process.
Next, this material was ground and blended in a mortar to an average particle radius of 10 μm or less.
This blended powder was sealingly inserted into a capsule and formed into tablets by compressing at a load of 50 kg/cm2. The methods may also be adopted in a hot press system where the tablet is heated while it is being pressed, or in which an electric current is applied to the tablet, so that a light elecrtric current flows through the tablet while the tablet is being heated.
Next, an oxidizing process was performed at between 500° C. and 1000° C., for example at 900° C., in an oxidizing atmosphere such as an atmosphere of highly purified oxygen, and full firing was carried out for 10 to 50 hours, for example, 15 hours.
Then this sample material was heated in a low oxygen O2 -Ar mixture (with other impurities at 10 ppm or less) for 3 to 30 hours at 600° C. to 1100° C., for example, and for 20 hours at 800° C., for reduction, resulting in a new structure which was observed clearly.
Using this sample material, the relationship between the specific resistance and temperature was determined. The highest temperature obtained for the Tc onset was observed to be 114° K, while the Tco was observed to be 103° K. The amount of impurities present was measured by means of a Secondary Ion Mass Spectrometer (SIMS). The amount of nitrogen and carbon dioxide were 0.1% or less by weight, specifically measured at only 0.01% by weight. The halogen elements detected were 0.1% or less by weight, specifically detected at only 0.001% by weight. The alkali metal elements were 0.2% or less by weight, specifically detected at only 0.001% by weight.
FIG. 1 shows the temperature versus specific resistance characteristics of the superconducting material of the present invention which was obtained n this example.
In Example 2 of the present invention, Yb was blended as the oxide compound. Ba was used as B, Sr as B-, with y:y- =1:1. As starting materials, ytterbium oxide and yttrium oxide were used. Barium carbonate(BaCO3) was used as the barium compound, and Sr2 O3 as the strontium compound. Also, CuO was used as the copper compound. In all other respects this example was the same as the first example.
The Tc onset obtained was 119° K, and Tco 107° K in this example.
This example was made on the basis of a conventional method for comparison.
As in Example 1, the starting materials were 3N in purity. The material was blended in the form of fine powders, but only a simple washing with city water being performed rather than ultrasonic washing with highly purified water. Other manufacturing conditions remained the same. The Tc in this case was only 92° K and Tco only 74° K. The results of analyses for impurities run on the formed tablets gave 0.3% by weight for sodium in the alkali metal elements, and 0.5% by weight for carbon and nitrogen.
similar processes were carried out except that other materials such as magnesium (Mg) and beryllium (Be) were used as B The results obtained was substantially the same as in the first example.
Claims (9)
1. A copper-oxide superconducting material which has a critical temperature Tco greater than 77° K, said material including alkali metal elements at less than 0.2 weight % and said ceramic material being generally represented as (A1-x Bx)y Cuz Ow, where x =0 to 1, y=2.0 to 4.0, z=1.5 to 3.5 and w=4.0 to 10.0, wherein A is an element selected from the group of Y (yttrium), Gd (gadolinium), Yb (ytterbium), Eu (europium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Lu (lutetium), Sc (scandium), and other lanthanides; and B is an element selected from among Ra (radium), Ba (barium), Sr (strontium), Ca (calcium), Mg (magnesium), and Be (beryllium).
2. The superconducting ceramic material of claim 1 wherein A is yttrium, and B is barium.
3. The superconducting ceramic material of claim 1 wherein said alkali metals are at least one of lithium, sodium, and potassium.
4. A copper-oxide superconducting material which has a critical temperature Tco greater than 77° K, said material including halogen elements at less than 0.1 weight % and said ceramic material being generally represented as (A1-x Bx)y Cuz Ow, where x=0 to 1, y=2.0 to 4.0, z=1.5 to 3.5 and w=4.0 to 10.0
wherein A is an element selected from the group of Y (yttrium), Gd (gadolinium), Yb (ytterbium), Eu (europium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Lu (lutetium), Sc (scandium), and other lanthanides; and B is an element selected from among Ra (radium), Ba (barium), Sr (strontium), Ca (calcium), Mg (magnesium), and Be (beryllium).
5. The superconducting ceramic material of claim 4 wherein A is yttrium, and B is barium.
6. The superconducting ceramic material of claim 4 wherein said halogen elements are at least fluorine.
7. A copper-oxide superconducting material which has a critical temperature Tco greater than 77° K, said material including alkali metal elements less than 0.2 weight %.
8. The superconducting ceramic material of claim 7 wherein said alkali metals are at least one of lithium, sodium, and potassium.
9. A copper-oxide superconducting material which has a critical temperature Tco greater than 77° K and a laminar structure including two layers of said copper-oxide;
wherein said material has the formula AB2 Cu3 Ow, in which A is at least one element selected from the group consisting of Y (yttrium), Gd (gadolinium), Yb (ytterbium), Eu (europium), Tb (terbium), Dy (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Lu (lutetium), Sc (scandium), and other lanthanides; B is at least one element selected from the group consisting of Ra (radium), Ba (barium), Sr (strontium), Ca (calcium), Mg (magnesium), and Be (beryllium), and w ranges from 6 to 8; and
wherein said material includes less than 0.2 weight % of alkali metal.
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US08/474,797 USH1683H (en) | 1987-03-27 | 1995-06-07 | Superconducting material |
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JP62075201A JP2630361B2 (en) | 1987-03-27 | 1987-03-27 | Superconducting material |
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US17442088A | 1988-03-25 | 1988-03-25 | |
US55079390A | 1990-07-06 | 1990-07-06 | |
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US08/474,797 USH1683H (en) | 1987-03-27 | 1995-06-07 | Superconducting material |
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EP (1) | EP0284438B1 (en) |
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Cited By (1)
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US20040077481A1 (en) * | 2001-03-13 | 2004-04-22 | Stefan Remke | Method for producing multinary metal oxide powders in a pulsed reactor |
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JP2597578B2 (en) * | 1987-05-11 | 1997-04-09 | 株式会社東芝 | Superconductor manufacturing method |
AU589068B2 (en) * | 1987-08-10 | 1989-09-28 | Furukawa Electric Co. Ltd., The | Method of manufacturing oxide superconductor, and method of manufacturing composite oxide powder which is the precursor of the oxide superconductor |
NZ228820A (en) * | 1989-04-19 | 1992-07-28 | Nz Scientific & Ind Res | Superconducting metal oxide and its preparation |
JP3217905B2 (en) * | 1992-06-26 | 2001-10-15 | キヤノン株式会社 | Metal oxide material and method for producing the same |
DE19603820A1 (en) * | 1995-08-04 | 1997-02-06 | Solvay Barium Strontium Gmbh | Superconductor premix |
CN110183473B (en) * | 2019-05-23 | 2021-09-14 | 深圳先进技术研究院 | Novel superconducting material and preparation method thereof |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4797510A (en) * | 1987-10-13 | 1989-01-10 | Amax, Inc. | Device for joining superconducting wire |
US4826808A (en) * | 1987-03-27 | 1989-05-02 | Massachusetts Institute Of Technology | Preparation of superconducting oxides and oxide-metal composites |
US4900715A (en) * | 1988-02-29 | 1990-02-13 | The United States Of America As Represented By The Secretary Of The Navy | Method of preparing superconducting "orthorhomibic"-type compounds in bulk using C1 -C6 alkanoic acid salts |
US4916116A (en) * | 1987-05-06 | 1990-04-10 | Semiconductor Energy Laboratory Co., Ltd. | Method of adding a halogen element into oxide superconducting materials by ion injection |
US4959345A (en) * | 1987-05-06 | 1990-09-25 | Semiconductor Energy Laboratory Co., Ltd. | Method of adding oxygen into oxide superconducting materials by ion injection |
US4971667A (en) * | 1988-02-05 | 1990-11-20 | Semiconductor Energy Laboratory Co., Ltd. | Plasma processing method and apparatus |
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JPS63230563A (en) * | 1987-03-18 | 1988-09-27 | Semiconductor Energy Lab Co Ltd | Superconducting ceramics |
JPS63230564A (en) * | 1987-03-18 | 1988-09-27 | Semiconductor Energy Lab Co Ltd | Superconducting ceramics |
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Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4826808A (en) * | 1987-03-27 | 1989-05-02 | Massachusetts Institute Of Technology | Preparation of superconducting oxides and oxide-metal composites |
US4916116A (en) * | 1987-05-06 | 1990-04-10 | Semiconductor Energy Laboratory Co., Ltd. | Method of adding a halogen element into oxide superconducting materials by ion injection |
US4959345A (en) * | 1987-05-06 | 1990-09-25 | Semiconductor Energy Laboratory Co., Ltd. | Method of adding oxygen into oxide superconducting materials by ion injection |
US4797510A (en) * | 1987-10-13 | 1989-01-10 | Amax, Inc. | Device for joining superconducting wire |
US4971667A (en) * | 1988-02-05 | 1990-11-20 | Semiconductor Energy Laboratory Co., Ltd. | Plasma processing method and apparatus |
US4900715A (en) * | 1988-02-29 | 1990-02-13 | The United States Of America As Represented By The Secretary Of The Navy | Method of preparing superconducting "orthorhomibic"-type compounds in bulk using C1 -C6 alkanoic acid salts |
Non-Patent Citations (23)
Title |
---|
"Band Properties and Superconductivity in La2-y Xy CuO4 ", Mattheiss, Physical Review Letters, vol. 58, No. 10, Mar. 9, 1987, pp. 1028-1030. |
"Evidence for Superconductivity above 40 K in the La-Ba-Cu-O Compound System", Chu et al., Physical Review Letters, vol. 58, No. 4, Jan. 26, 1987, pp. 405-407. |
"High-Pressure Study of the New Y-Ba-Cu-O Superconducting Compound System", Hor et al., Physical Review Letters, vol. 58, No. 9, Mar. 2, 1987, pp. 911-912. |
"Lattice Instability and High-T Superconductivity in La2-x Bax CuO4 ", Jorgansen et al., Physical Review Letters, vol. 58, No. 10, Mar. 9, 1987, pp. 1024-1027. |
"Possible High Tc Superconductivity in the Ba-La-Cu-O System", Bednorz et al., Condensed Matter, 64, 1986, pp. 189-193. |
"Preparation and Properties of the Compounds Ln2 CuO4 (Ln=La, Pr, Nd, Sm, Eu, Gd) and Some of Their Solid Solutions", Shaplygin et al., Russian Journal of Inorganic Chemistry, 24(6), 1979, pp. 820-824. |
"Superconductivity above Liquid Nitrogen Temperature: Preparation and Properties of a Family of Perovskite-Based Superconductors", Engler et al., J. Am. Chem. Soc., 109, 1987, pp. 2848-2849. |
"Superconductivity at 40K in La8 SiO2 CuO4 ", Politts et al., Condensed Matter, 66, 1987, pp. 141-144. |
"Superconductivity at 52.5 K in the Lanthanum-Barium-Copper-Oxide System", Chu et al., Reports, Jan. 30, 1987, pp. 567-569. |
Band Properties and Superconductivity in La 2 y X y CuO 4 , Mattheiss, Physical Review Letters, vol. 58, No. 10, Mar. 9, 1987, pp. 1028 1030. * |
Chemical Abstracts, CA 109:161912, for BR 8,702,554 (Nov. 1987). * |
Engler, E.M., et al., "Processing, Structure, and High-Temperature Superconductivity", Chemistry of High-Temperature Superconductors, ACS Symposium Series, 351 (1987), pp. 266-271. |
Engler, E.M., et al., Processing, Structure, and High Temperature Superconductivity , Chemistry of High Temperature Superconductors, ACS Symposium Series, 351 (1987), pp. 266 271. * |
Evidence for Superconductivity above 40 K in the La Ba Cu O Compound System , Chu et al., Physical Review Letters, vol. 58, No. 4, Jan. 26, 1987, pp. 405 407. * |
High Pressure Study of the New Y Ba Cu O Superconducting Compound System , Hor et al., Physical Review Letters, vol. 58, No. 9, Mar. 2, 1987, pp. 911 912. * |
Lattice Instability and High T Superconductivity in La 2 x Ba x CuO 4 , Jorgansen et al., Physical Review Letters, vol. 58, No. 10, Mar. 9, 1987, pp. 1024 1027. * |
Possible High T c Superconductivity in the Ba La Cu O System , Bednorz et al., Condensed Matter, 64, 1986, pp. 189 193. * |
Preparation and Properties of the Compounds Ln 2 CuO 4 (Ln La, Pr, Nd, Sm, Eu, Gd) and Some of Their Solid Solutions , Shaplygin et al., Russian Journal of Inorganic Chemistry, 24(6), 1979, pp. 820 824. * |
Superconductivity above Liquid Nitrogen Temperature: Preparation and Properties of a Family of Perovskite Based Superconductors , Engler et al., J. Am. Chem. Soc., 109, 1987, pp. 2848 2849. * |
Superconductivity at 40K in La 8 SiO 2 CuO 4 , Politts et al., Condensed Matter, 66, 1987, pp. 141 144. * |
Superconductivity at 52.5 K in the Lanthanum Barium Copper Oxide System , Chu et al., Reports, Jan. 30, 1987, pp. 567 569. * |
Tarascon, J.M., et al., "Oxygen and rare-earth doping of the 90-K superconducting perovskite YBa2 Cu3 O7-x ", Physical Review B, 36(1) (1 Jul. 1987), 226-234. |
Tarascon, J.M., et al., Oxygen and rare earth doping of the 90 K superconducting perovskite YBa 2 Cu 3 O 7 x , Physical Review B, 36(1) (1 Jul. 1987), 226 234. * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040077481A1 (en) * | 2001-03-13 | 2004-04-22 | Stefan Remke | Method for producing multinary metal oxide powders in a pulsed reactor |
US7358212B2 (en) * | 2001-03-13 | 2008-04-15 | Merck Patent Gmbh | Method for producing multinary metal oxide powders in a pulsed reactor |
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JPS63239110A (en) | 1988-10-05 |
DE3856473T2 (en) | 2001-09-13 |
CN88101627A (en) | 1988-10-19 |
KR950004294B1 (en) | 1995-04-28 |
EP0284438B1 (en) | 2001-05-30 |
KR880011831A (en) | 1988-10-31 |
DE3856473D1 (en) | 2001-07-05 |
EP0284438A2 (en) | 1988-09-28 |
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JP2630361B2 (en) | 1997-07-16 |
CN1032777C (en) | 1996-09-11 |
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