WO1991011391A1 - Compositions d'oxydes metalliques supraconductrices - Google Patents

Compositions d'oxydes metalliques supraconductrices Download PDF

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Publication number
WO1991011391A1
WO1991011391A1 PCT/US1991/000014 US9100014W WO9111391A1 WO 1991011391 A1 WO1991011391 A1 WO 1991011391A1 US 9100014 W US9100014 W US 9100014W WO 9111391 A1 WO9111391 A1 WO 9111391A1
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Prior art keywords
composition
superconducting
temperature
compositions
formula
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PCT/US1991/000014
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English (en)
Inventor
Munirpallam Appadorai Subramanian
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E.I. Du Pont De Nemours And Company
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Publication date
Application filed by E.I. Du Pont De Nemours And Company filed Critical E.I. Du Pont De Nemours And Company
Publication of WO1991011391A1 publication Critical patent/WO1991011391A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G15/00—Compounds of gallium, indium or thallium
    • C01G15/006—Compounds containing, besides gallium, indium, or thallium, two or more other elements, with the exception of oxygen or hydrogen
    • 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
    • C04B35/4512—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 thallium oxide
    • 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

Definitions

  • This invention relates to novel Tl-(La,Nd,Pr)- Sr-Ca-Cu-0 single phase compositions which are superconducting.
  • Background Art Bednorz and uller, Z. Phys. B64, . 189 (1986), disclose a superconducting phase in the La-Ba-Cu-0 system with a superconducting transition temperature of about 35 K. The existence of this phase was subsequently confirmed by a number of investigators [see, for example, Rao and Ganguly, Current Science, 56, 47 (1987), Chu et al., Science 235, 567 (1987), Chu et al., Phys. Rev. Lett. 58, 405 (1987), Cava et al., Phys. Rev. Lett. 58, 408 (1987), Bednorz et al., Europhys. Lett. 3, 379 (1987)].
  • the superconducting phase has been identified as the composition
  • the material made from ultrapure oxides has a superconducting transition with a midpoint of 22 K, as determined from resistivity measurements and zero resistance below 14 K.
  • the material made from commercial grade oxides has a superconducting transition with a midpoint of 7 K.
  • H. Maeda et al., Jpn. J. Appl. Phys. 27, L209 (1988) disclose a superconducting oxide in the Bi-Sr-Ca-Cu-0 system with the composition near
  • BiSrCaCu2 ⁇ x BiSrCaCu2 ⁇ x and a superconducting transition temperature of about 105 K.
  • the high-Tc phase shows an onset of superconductivity at around 115 K.
  • a+e is about 1
  • b is about 2
  • c is about 2
  • d is from about 1/2 to about 2.
  • the onset of superconductivity for these compositions is at least 70 K.
  • Tl/Bi was about 1
  • y was about 7
  • T c was about 95 K.
  • TlSr2Cao.5Ero.5Cu2O6.75 which has a T c of 34 K.
  • This invention provides novel single phase superconducting compositions having the formula TlR x Sr2- x CaC 2 ⁇ 7 wherein R is at least one element chosen from the group consisting of Nd, Pr and La and 0.2 ⁇ x ⁇ 0.8.
  • R is at least one element chosen from the group consisting of Nd, Pr and La and 0.2 ⁇ x ⁇ 0.8.
  • x is from about 0.4 to about 0.6, most preferably about 0.5.
  • R is La.
  • These superconducting compositions are prepared by heating a mixture of the Tl, R, Sr, Ca and Cu oxides, the relative amounts chosen so that the atomic ratio Tl:R:Sr:Ca:Cu is l:x:2-x:l:2, to a temperature of about
  • the heating temperature is preferably about 890-900 * C.
  • FIG. 1 shows a plot of the flux excluded by a composition of the formula TlNdo. Sr ⁇ . CaC 2 ⁇ 7 as a function of temperature.
  • the superconducting compositions of this invention are prepared by the following process. Quantities of the oxide reactants TI2O3, Sr ⁇ 2, Ca ⁇ 2, CuO and at least one of the R-oxides, Nd2 ⁇ 3, PreOn and La2 ⁇ 3, are chosen to provide an atomic ratio of Tl:R:Sr:Ca:Cu of l:x:2- x:l:2 where 0.2 ⁇ x ⁇ 0.8 and are mixed, for example, by grinding them together in a mortar. The mixed powder may then be heated directly or it can be first formed into a pellet or other shaped object and then heated. The superconducting composition of this invention is produced only when the environment in which the reactants are heated is carefully controlled.
  • This controlled environment must prevent (1) the escape of the metals and the oxygen and (2) their reaction with other elements.
  • One way to provide a controlled environment is to place the reactants in an air-filled container, e.g. a tube, made of a non-reacting metal such as gold and then seal the tube by welding.
  • the sealed tube is then placed in a furnace and heated to about 880'C to about 910"C, preferably about 890-900 * C, and maintained at that temperature for about 6 to 12 hours.
  • the sealed tube is then cooled to ambient temperature. For example, the power to the furnace is turned off and the tube is furnace-cooled to ambient temperature, about 20 * C, and then removed from the furnace.
  • the tube is then opened and the black single phase product recovered.
  • compositions of the invention prepared in this manner exhibit superconductivity and those with x near the middle of the indicated range, i. e., with x about 0.5, exhibit the highest onset of superconductivity with the onset occuring above 77 K.
  • the lattice parameters of these superconducting compositions have been determined from X-ray diffraction powder pattern results indexed on a tetragonal unit cell.
  • the lattice parameter a increases slightly and the lattice parameter c decreases slightly as x increases.
  • compositions of this invention include those compositions in which the amount of oxygen per formula unit deviates somewhat from the 7 indicated by the formula TlR x Sr2- CaCu2 ⁇ 7 but which are single phase superconducting compositions with tetragonal unit cell parameters consistent with those given above. Typically, such deviations in the amount of oxygen would be less than about 5% of the amount of oxygen indicated by the given formula.
  • Superconductivity can be confirmed by observing magnetic flux exclusion, i. e., the Meissner effect. This effect can be measured by the method described in an article by E. Polturak and B. Fisher in Physical Review B, 36, 5586(1987).
  • the superconducting compositions of this invention can be used to conduct current extremely efficiently or to provide a magnetic field for magnetic imaging for medical purposes or for particle accelerators.
  • T c superconducting transition temperature
  • the wire mentioned previously could be wound to form a coil or solenoid which would be exposed to liquid helium or liquid nitrogen before inducing any current into the coil.
  • Such fields can also be used to levitate objects as large as railroad cars.
  • These superconducting compositions are also useful in thin film-based Josephson devices such as SQUIDS (superconducting quantum interference devices) and in instruments that are based on the Josephson effect such as high speed sampling circuits and voltage standards.
  • the tube was placed in a furnace and heated at a rate of about 5 * C per minute to 890"C and then maintained at 890"C for 6 hours. Power to the furnace was then shut off and the tube was allowed to cool to room temperature in the furnace. The tube was then removed from the furnace and cut open. The black product was recovered. Meissner effect measurements were carried out and the results showed that the products of Experiments A, B, D, E, G and H were not superconductors at temperatures down to about 4 K. Meissner effect measurements were carried out and the results showed that the products of Experiments C, F and I showed an onset of superconductivity at about the temperature shown in Table II.
  • X-ray diffraction powder patterns of the products of Experiments C, F and I showed that these products were not single phase and the formula shown in Table II for each of these Experiments is a nominal one.
  • X-ray diffraction powder patterns of the products of Experiments A, B, D, E, G and H showed that these products were essentially single phase and the lattice parameters are shown in Table II along with- the formula of the composition.
  • Examples A, B, D, E, G and H are essentially single phase but are not superconductors.
  • the products of Examples C, F and I exhibit superconductivity but are multiphase.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Compositions Of Oxide Ceramics (AREA)

Abstract

Les compositions ayant la formule TlRxSr2-xCaCu2O7, dans laquelle R représente au moins un élément choisi dans le groupe composé de Nd, Pr et La, et 0,2 < x < 0,8, sont supraconductrices.
PCT/US1991/000014 1990-01-26 1991-01-08 Compositions d'oxydes metalliques supraconductrices WO1991011391A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US47119690A 1990-01-26 1990-01-26
US471,196 1990-01-26

Publications (1)

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WO1991011391A1 true WO1991011391A1 (fr) 1991-08-08

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PCT/US1991/000014 WO1991011391A1 (fr) 1990-01-26 1991-01-08 Compositions d'oxydes metalliques supraconductrices

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AU (1) AU7242891A (fr)
WO (1) WO1991011391A1 (fr)

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
JAPANESE JOURNAL OF APPLIED PHYSICS, Volume 28, Number 6, June 1989, NAGASHIMA et al., "Improving Superconducting Characteristics of Tl-Sr-Ca-Cu-O by Doping with Pb and/or Rare-Earth Elements", pages L930-L933. *
JOURNAL PHYSICS D: APPLIED PHYSICS, Volume 22, 1989, ZHANG et al., "The preparation and Superconductivity of the New Superconducting Systems R-Tl-Sr-Ca-Cu-O (R=Nd,Sm,Er,Gd)", pages 1364-1365. *
PHASE TRANSITIONS, Volume 19, 1989, GANGULI et al., "Novel 1122 Thallium Cuprates Showing High Tc Superconductivity: TlCa1-xYxBa2Cu2Oy, Tl1-xPbxCaSr2Cu2Oy and TlCa0.5Ln0.5Sr2Cu2Oy", pages 213-222. *
PHYSICAL REVIEW B, Volume 39, Number 4, 01 Februaruy 1989, SHENG et al., "Superconductivity Above 77K in the R-T1-Sr-Ca-Cu-O system (R Represents Rare Earths)", pages 2918-20. *
PHYSICAL REVIEW B, Volume 40, Number 4, 01 August 1989, RAO et al., "Superconducting (1:1:2:2)-Type Layered Cuprates of the Formula T1Ca1-xLxSr2Cu2Oy (L=Y or a Rare-Earth Element)", pages 2565-67. *
PHYSICAL STATUS SOLIDI (a), 114, August 1989, LIANG et al., "The Crystal Structure and Superconductivity of the Superconducting Phase T1Sr2 (Ca, La), Cu2O7", pages 651-8. *
SUPERCONDUCTOR: SCIENCE AND TECHNOLOGY, Volume 2, Number 3, September 1989, VIJAYARAGHARAN et al., "Investigations of Novel Cuprates of the T1Ca1-xLnxSr2Cu2O7-y (Ln= Rare Earth) Series Showing Electron- or Hole-Superconductivity Depending on Compositions", pages 195-201. *

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Publication number Publication date
AU7242891A (en) 1991-08-21

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