CA1341237C - Superconducting metal oxide compositions and process for manufacture - Google Patents
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- CA1341237C CA1341237C CA000590128A CA590128A CA1341237C CA 1341237 C CA1341237 C CA 1341237C CA 000590128 A CA000590128 A CA 000590128A CA 590128 A CA590128 A CA 590128A CA 1341237 C CA1341237 C CA 1341237C
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- 229910044991 metal oxide Inorganic materials 0.000 title claims abstract description 14
- 150000004706 metal oxides Chemical class 0.000 title claims abstract description 14
- 239000000203 mixture Substances 0.000 title abstract description 44
- 238000000034 method Methods 0.000 title abstract description 8
- 238000004519 manufacturing process Methods 0.000 title abstract description 3
- 239000008188 pellet Substances 0.000 description 30
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 17
- 238000005259 measurement Methods 0.000 description 17
- 239000000843 powder Substances 0.000 description 17
- 230000000694 effects Effects 0.000 description 16
- 230000007704 transition Effects 0.000 description 14
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 13
- 239000004570 mortar (masonry) Substances 0.000 description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 229910000019 calcium carbonate Inorganic materials 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000007788 liquid Substances 0.000 description 5
- 230000005291 magnetic effect Effects 0.000 description 5
- 239000002243 precursor Substances 0.000 description 5
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 4
- 239000010931 gold Substances 0.000 description 4
- 229910052737 gold Inorganic materials 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 229910002480 Cu-O Inorganic materials 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- -1 e.g. Chemical class 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 229910009203 Y-Ba-Cu-O Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 230000005493 condensed matter Effects 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 230000007717 exclusion Effects 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 150000002823 nitrates Chemical class 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 230000005668 Josephson effect Effects 0.000 description 1
- OSOKRZIXBNTTJX-UHFFFAOYSA-N [O].[Ca].[Cu].[Sr].[Bi] Chemical compound [O].[Ca].[Cu].[Sr].[Bi] OSOKRZIXBNTTJX-UHFFFAOYSA-N 0.000 description 1
- 150000001242 acetic acid derivatives Chemical class 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000003776 cleavage reaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 230000005292 diamagnetic effect Effects 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000002524 electron diffraction data Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000004108 freeze drying Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 238000002173 high-resolution transmission electron microscopy Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- IBIKHMZPHNKTHM-RDTXWAMCSA-N merck compound 25 Chemical compound C1C[C@@H](C(O)=O)[C@H](O)CN1C(C1=C(F)C=CC=C11)=NN1C(=O)C1=C(Cl)C=CC=C1C1CC1 IBIKHMZPHNKTHM-RDTXWAMCSA-N 0.000 description 1
- CJJMLLCUQDSZIZ-UHFFFAOYSA-N oxobismuth Chemical compound [Bi]=O CJJMLLCUQDSZIZ-UHFFFAOYSA-N 0.000 description 1
- 230000002085 persistent effect Effects 0.000 description 1
- 238000000634 powder X-ray diffraction Methods 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 230000007017 scission Effects 0.000 description 1
- 238000000373 single-crystal X-ray diffraction data Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001694 spray drying Methods 0.000 description 1
- 239000002887 superconductor Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/02—Oxides or hydroxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G29/00—Compounds of bismuth
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Superconductor Devices And Manufacturing Methods Thereof (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Abstract
Compositions having the nominal formula Bi a Sr b Ca c Cu3O x wherein a is from about 1 to 3, b is from about 3/8 to 4, c is from about 3/16 to 2, x = (1.5a + b + c + y) where y is from about 2 to 5, with the proviso that "b + c" is from about 3/2 to 5, containing a metal oxide phase of the formula Bi, Sr3-z, Ca z, Cu2, O8+w wherein z is from about 0.1 to 0.9 w is greater than zero but less than 1, are superconducting. Processes for manufacturing such compositions and for using them are disclsoed.
Description
TlTf.F
SUf'ERCONDUCTING METAL OXIDE COMPOSITIONS
AND PROCESS FOR MANUFACTURE
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to novel bismuth-strontium-calcium-copper oxide compositions which ace superconducting and to a process for making them.
References Bednocz and Muller, Z. Phys. 864, 189 (1986), disclose a superconducting phase in the La-Ba-Cu-0 system with a superconducting transition temperature of about 35 K. This disclosure 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)J. The superconducting phase has been identified as the composition Lar_k(Ba,Sr,Ca) , with the tetragonal 04_ x s KzNiF~-type structure and with x typically about 0.15 and y indicating oxygen vacancies.
wu et al., Phys. Rev. Lett. 58, 908 (1987), disclose a superconducting phase in the Y-Ba-Cu-O system with a superconducting transition temperature of about 90 K. Cava et al., Phys.
Rev. Lett. 58, 1676 (1987), have identified this supercon<~lucting Y-Ba-Cu-O phase to be orthorhomt~ic, distorted, oxygen-deficient where b is about 2.1 and perovskite YBa Cu O
I
~
q_b CR-8641-A 35 present the powder x-ray diffraction pattern and lattice parameters.
~34123~
C. Michel et al., Z. Phys. B - Condensed Matter 68, 417 (1987), disclose the introduction of Bi into the superconductor Laz_~Sr~CuOq_Y to form the oxides La2 _ x Bix , Sr% _ K , CuOQ _ Y . The study 5 was limited to compositions corresponding to the range where superconductivity was mainly observed, x - x' = 0.1-0.2. Single phases were obtained when x < 3 and x' < 2. One sample of composition Lar . ~ eip . r Sro . Z CuO~ _Y has a superconducting 10 transition temperature of about 42 K as determined from resistivity measurements as compared with about 38 K for Lal . a Sra , Z Cu04 Y
C. Michel et al., Z. Phys. B - Condensed Matter 68, 421 (1987), disclose a novel family of 15 superconducting oxides in the Bi-Sr-Cu-O system with composition close to Bi2SrZCu20~~a . A pure phase was isolated for the composition BiZSrZCuZO~rb . The X-ray diffraction pattern for this material exhibits some similarity with that 20 of perovskite and the electron diffraction pattern shows the perovskite subcell with the orthorhombic cell parameters of a - 5.32 A (0.532 nm), b = 26.6 A (2.66 nm) and c ~ 48.8 A (4.88 nm). The material made from ultrapure oxides has a 25 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.
SUMM11RY OF TfiE I NVENTION
This invention provides novel superconducting compositions having the nominal formula Bi~Sr~ Ca~Cu~Ox wherein a is from about 1 35 to about 2, b is from about 3/8 to about 4, c is from about 3/4 to about 2 and x = (1.5 a + b + c +
y) where y is from about 2 to about 5, with the proviso that b + c is from about 3/2 to about S, said compositions having superconducting S transition temperatures of about 70 K or higher.
Preferably, a is from about 3/2 to about 2, b is from about 3/2 to about 4, c is from about 1 to about 3/2 and b + c is about 3-5. The superconducting transition temperature of the 10 preferred composition will be from at least 77 K
(liquid nitrogen) up to about 115 K.
This invention also comprises a definition of the metal oxide phases that provides superconductivity for the composition of the 15 nominal formula previously given. Specifically, this metal oxide phase has the formula BiZ Sr3 _ Z CaL Cu2 Oe '~
wherein z is from about 0.1 to about 0.9, preferably 0.4 to 0.8 and most preferably 0.6 to 20 0.7; and w is greater than zero but less than about 1.
Thus, the nominal formula for these superconducting compositions that contain 25 substantial amounts of the above-mentioned metal oxide phase that provides superconductivity becomes Bi~ Srb Ca~ Cuj Ox wherein a is from about 1 to about 3, b is from about 3/8 to about 4, c is from about 3/16 to 30 about 2 and x - (1.5a + b+ c + y) where y is from about 2 to about 5, with the proviso that b + c is from about 3/2 to about 5.
This invention also provides a process for making these compositions, the process 35 consisting essentially of heating a mixture comprised of stoichiometric quantities of the metal oxides, for example, BiiO~, Sr0 or SrOZ, CaO, and CuO, or precursors of the metal oxides, e.g., carbonates such as CaCOj, nitrates such as Sr(N0~)z, etc. at about 775°C to about 900°C for 5 about 8 to about 48 hours or more in air.
Preferred are heating temperatures of about 850°C
to about 900°C.
DETAILED DESCRIPTION OF THE INVENTION
10 The superconducting compositions of this invention have the nominal formula Bi~SrbCa~Cu~Ox wherein a is from about 1 to about 3, b is from about 3/8 to about 4, c is from about 3/16 to about 2 and x ~ ( 1 . S a + b + c + y) where y is 15 from about 2 to about 5, with the proviso that b +
c is from about 3/2 to about 5. These compositions have superconducting transition temperatures of at least 70 K up to about 120 K.
Preferred are the compositions wherein a is from 20 about 3/2 to about 3, b is from about 3/2 to about 4, c is from about 1/2 to about 3/2 and b + c is about 3-5. These preferred compositions have superconducting transition temperatures above 77 K, the temperature of liquid nitrogen.
25 The superconducting Bie SrbCa~ Cu3 Ox compositions can be prepared by the following process. Stoichiometric quantities of Bi203, SrO, CaO, and Cu0 are mixed, for example, by grinding them together in a mortar. Precursors of the 30 oxides such as carbonates can be substituted for one or more of the oxides. Alternatively, an intimate stoichiometric mixture of precursors of the oxides can be prepared from a solution of precursors such as nitrates or acetates, either by 35 precipitation from such a solution or by drying such a solution by evaporation of the solvent or by spray- or freeze-drying. The mixture of oxides or precursors in the form of a powder or a pressed pellet is then placed in a container made of a non-reactive material such as alumina or gold.
5 The container is then placed in a furnace and heated at about 775°C to about 900°C for about 8 to about 48 hours in air, preferably from about 850°C to about 900°C. The superconducting transition temperature is generally higher if the 10 heating temperature is in the preferred range.
Melting should be avoided. Since melting occurs at heating temperatures of about 900°C and higher, reaction must occur below these temperatures.
Cooling can be done slowly by either 15 turning off the power to the furnace and allowing the container to furnace-cool or by programming the furnace to cool at a slow rate, e. g., at 2°C
per minute. When the temperature is below 100°C, e.g. ambient temperature (about 20°C) the 20 container is removed from the furnace and the black crystalline product is recovered. Cooling can also be accomplished by quenching at ambient temperature the material which had been heated to 850-900° C.
25 A superconducting Bis Srb Ca~ Cu3 OX
composition can be produced even when the relative amounts of reactants are chosen outside of the stoichiomeric limits dictated by the ranges enumerated above for a, b and c. The 30 superconducting composition would then be composed of at least one superconducting phase along with other non-superconducting phases.
Superconductivity can be confirmed by observing magnetic flux exclusion, i.e., the 35 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 5 efficiently or to provide a magnetic field for magnetic imaging for medical purposes. Thus, by cooling the composition in the form of a wire or bar to a temperature below the superconducting transition temperature, e.g., at or below about 10 115 K, preferably at or below about 85 K, by exposing the material to liquid nitrogen in a manner well known to those in this field; and initiating a flow of electrical current, one can obtain such flow without any electrical resistive 15 losses. To provide exceptionally high magnetic fields with minimal power losses, the wire mentioned previously could be wound to form a coil which would be exposed to liquid helium before inducing any current into the coil. The 20 superconducting compositions of this invention can also be used to provide diamagnetic fields that are extremely persistent. Such fields are obtained by exposing the compositions in the form of a sheet or similar construction to an external 25 magnetic field, the sheet being cooled to a temperature below the superconducting transition temperature, e.g. cooled to between 77 K and 115 K, by exposure to liquid nitrogen. Such fields can be used to levitate objects as large as 30 railroad cars. These superconducting compositions are also useful in Josephson devices such as SQUIDS (superconducting quantum interference devices) and in instruments that are based on the Josephson effect such as high speed sampling 35 circuits and voltage standards. These compositions appear to be more stable, especially in the presence of water, than prior superconductive compositions having transition temperatures in the same range. The compositions are also more easily processed than prior art 5 compositions.
cvnrnor c t 10 A compositor of nominal formula BiSrCaCu30x was prepared in the following manner.
BiZOi (2.3298 g), SrOi (1.1692 g), CaCO~ (1.0009 g) and Cu0 (2.3862 g) were mixed and ground together in an agate mortar for thirty minutes.
15 The powder was placed in an alumina container and the container placed in a furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 12 hours. The power was then turned off and the furnace allowed to cool to a 20 temperature below about 100°C before the container was removed. The black crystalline product was recovered.
Measurement of the Meissner effect showed the powder product to have an onset of 25 superconductivity at about 75 K.
~vnMOr c 7 A compositor of nominal formula Bi~~~Srj~ZCai~2CujOx was prepared in the following 30 manner. eiz03 (4.6596 g), SrOz (2.3924 g), CaCO~
(2.0018 g) and Cu0 (3.1816 g) were mixed and ground together in an agate mortar for thirty minutes. The powder was placed in an alumina container and the container placed in a furnace 35 and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 12 hours. The 13 4'~ 237 power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the container was removed. The black crystalline product was recovered.
5 Measurement of the Meissner effect showed the powder product to have an onset of superconductivity at about 75 K.
10 A compositon of nominal formula BiZSr2CaCu~Ox was prepared in the following manner. Bi~03 (4.6596 g), SrOZ (2.3924 g), CaC03 (1.0009 g) and Cu0 (2.3865 g) were mixed and ground together in an agate mortar for thirty 15 minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
In Example 3A, the pressed pellet was placed on an alumina tray and the tray placed in a 20 furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 8 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the tray was removed. The 25 black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 83 K.
In Example 3B, another pressed pellet 30 was placed on an alumina tray and the tray placed in a furnace and heated in air at a rate of 10°C
per minute to 900°C and then held at 900°C for 8 hours. The furnace was then cooled at the rate of 2°C per minute to a temperature below about 100°C
35 before the tray was removed. The black crystalline product was recovered.
SUf'ERCONDUCTING METAL OXIDE COMPOSITIONS
AND PROCESS FOR MANUFACTURE
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to novel bismuth-strontium-calcium-copper oxide compositions which ace superconducting and to a process for making them.
References Bednocz and Muller, Z. Phys. 864, 189 (1986), disclose a superconducting phase in the La-Ba-Cu-0 system with a superconducting transition temperature of about 35 K. This disclosure 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)J. The superconducting phase has been identified as the composition Lar_k(Ba,Sr,Ca) , with the tetragonal 04_ x s KzNiF~-type structure and with x typically about 0.15 and y indicating oxygen vacancies.
wu et al., Phys. Rev. Lett. 58, 908 (1987), disclose a superconducting phase in the Y-Ba-Cu-O system with a superconducting transition temperature of about 90 K. Cava et al., Phys.
Rev. Lett. 58, 1676 (1987), have identified this supercon<~lucting Y-Ba-Cu-O phase to be orthorhomt~ic, distorted, oxygen-deficient where b is about 2.1 and perovskite YBa Cu O
I
~
q_b CR-8641-A 35 present the powder x-ray diffraction pattern and lattice parameters.
~34123~
C. Michel et al., Z. Phys. B - Condensed Matter 68, 417 (1987), disclose the introduction of Bi into the superconductor Laz_~Sr~CuOq_Y to form the oxides La2 _ x Bix , Sr% _ K , CuOQ _ Y . The study 5 was limited to compositions corresponding to the range where superconductivity was mainly observed, x - x' = 0.1-0.2. Single phases were obtained when x < 3 and x' < 2. One sample of composition Lar . ~ eip . r Sro . Z CuO~ _Y has a superconducting 10 transition temperature of about 42 K as determined from resistivity measurements as compared with about 38 K for Lal . a Sra , Z Cu04 Y
C. Michel et al., Z. Phys. B - Condensed Matter 68, 421 (1987), disclose a novel family of 15 superconducting oxides in the Bi-Sr-Cu-O system with composition close to Bi2SrZCu20~~a . A pure phase was isolated for the composition BiZSrZCuZO~rb . The X-ray diffraction pattern for this material exhibits some similarity with that 20 of perovskite and the electron diffraction pattern shows the perovskite subcell with the orthorhombic cell parameters of a - 5.32 A (0.532 nm), b = 26.6 A (2.66 nm) and c ~ 48.8 A (4.88 nm). The material made from ultrapure oxides has a 25 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.
SUMM11RY OF TfiE I NVENTION
This invention provides novel superconducting compositions having the nominal formula Bi~Sr~ Ca~Cu~Ox wherein a is from about 1 35 to about 2, b is from about 3/8 to about 4, c is from about 3/4 to about 2 and x = (1.5 a + b + c +
y) where y is from about 2 to about 5, with the proviso that b + c is from about 3/2 to about S, said compositions having superconducting S transition temperatures of about 70 K or higher.
Preferably, a is from about 3/2 to about 2, b is from about 3/2 to about 4, c is from about 1 to about 3/2 and b + c is about 3-5. The superconducting transition temperature of the 10 preferred composition will be from at least 77 K
(liquid nitrogen) up to about 115 K.
This invention also comprises a definition of the metal oxide phases that provides superconductivity for the composition of the 15 nominal formula previously given. Specifically, this metal oxide phase has the formula BiZ Sr3 _ Z CaL Cu2 Oe '~
wherein z is from about 0.1 to about 0.9, preferably 0.4 to 0.8 and most preferably 0.6 to 20 0.7; and w is greater than zero but less than about 1.
Thus, the nominal formula for these superconducting compositions that contain 25 substantial amounts of the above-mentioned metal oxide phase that provides superconductivity becomes Bi~ Srb Ca~ Cuj Ox wherein a is from about 1 to about 3, b is from about 3/8 to about 4, c is from about 3/16 to 30 about 2 and x - (1.5a + b+ c + y) where y is from about 2 to about 5, with the proviso that b + c is from about 3/2 to about 5.
This invention also provides a process for making these compositions, the process 35 consisting essentially of heating a mixture comprised of stoichiometric quantities of the metal oxides, for example, BiiO~, Sr0 or SrOZ, CaO, and CuO, or precursors of the metal oxides, e.g., carbonates such as CaCOj, nitrates such as Sr(N0~)z, etc. at about 775°C to about 900°C for 5 about 8 to about 48 hours or more in air.
Preferred are heating temperatures of about 850°C
to about 900°C.
DETAILED DESCRIPTION OF THE INVENTION
10 The superconducting compositions of this invention have the nominal formula Bi~SrbCa~Cu~Ox wherein a is from about 1 to about 3, b is from about 3/8 to about 4, c is from about 3/16 to about 2 and x ~ ( 1 . S a + b + c + y) where y is 15 from about 2 to about 5, with the proviso that b +
c is from about 3/2 to about 5. These compositions have superconducting transition temperatures of at least 70 K up to about 120 K.
Preferred are the compositions wherein a is from 20 about 3/2 to about 3, b is from about 3/2 to about 4, c is from about 1/2 to about 3/2 and b + c is about 3-5. These preferred compositions have superconducting transition temperatures above 77 K, the temperature of liquid nitrogen.
25 The superconducting Bie SrbCa~ Cu3 Ox compositions can be prepared by the following process. Stoichiometric quantities of Bi203, SrO, CaO, and Cu0 are mixed, for example, by grinding them together in a mortar. Precursors of the 30 oxides such as carbonates can be substituted for one or more of the oxides. Alternatively, an intimate stoichiometric mixture of precursors of the oxides can be prepared from a solution of precursors such as nitrates or acetates, either by 35 precipitation from such a solution or by drying such a solution by evaporation of the solvent or by spray- or freeze-drying. The mixture of oxides or precursors in the form of a powder or a pressed pellet is then placed in a container made of a non-reactive material such as alumina or gold.
5 The container is then placed in a furnace and heated at about 775°C to about 900°C for about 8 to about 48 hours in air, preferably from about 850°C to about 900°C. The superconducting transition temperature is generally higher if the 10 heating temperature is in the preferred range.
Melting should be avoided. Since melting occurs at heating temperatures of about 900°C and higher, reaction must occur below these temperatures.
Cooling can be done slowly by either 15 turning off the power to the furnace and allowing the container to furnace-cool or by programming the furnace to cool at a slow rate, e. g., at 2°C
per minute. When the temperature is below 100°C, e.g. ambient temperature (about 20°C) the 20 container is removed from the furnace and the black crystalline product is recovered. Cooling can also be accomplished by quenching at ambient temperature the material which had been heated to 850-900° C.
25 A superconducting Bis Srb Ca~ Cu3 OX
composition can be produced even when the relative amounts of reactants are chosen outside of the stoichiomeric limits dictated by the ranges enumerated above for a, b and c. The 30 superconducting composition would then be composed of at least one superconducting phase along with other non-superconducting phases.
Superconductivity can be confirmed by observing magnetic flux exclusion, i.e., the 35 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 5 efficiently or to provide a magnetic field for magnetic imaging for medical purposes. Thus, by cooling the composition in the form of a wire or bar to a temperature below the superconducting transition temperature, e.g., at or below about 10 115 K, preferably at or below about 85 K, by exposing the material to liquid nitrogen in a manner well known to those in this field; and initiating a flow of electrical current, one can obtain such flow without any electrical resistive 15 losses. To provide exceptionally high magnetic fields with minimal power losses, the wire mentioned previously could be wound to form a coil which would be exposed to liquid helium before inducing any current into the coil. The 20 superconducting compositions of this invention can also be used to provide diamagnetic fields that are extremely persistent. Such fields are obtained by exposing the compositions in the form of a sheet or similar construction to an external 25 magnetic field, the sheet being cooled to a temperature below the superconducting transition temperature, e.g. cooled to between 77 K and 115 K, by exposure to liquid nitrogen. Such fields can be used to levitate objects as large as 30 railroad cars. These superconducting compositions are also useful in Josephson devices such as SQUIDS (superconducting quantum interference devices) and in instruments that are based on the Josephson effect such as high speed sampling 35 circuits and voltage standards. These compositions appear to be more stable, especially in the presence of water, than prior superconductive compositions having transition temperatures in the same range. The compositions are also more easily processed than prior art 5 compositions.
cvnrnor c t 10 A compositor of nominal formula BiSrCaCu30x was prepared in the following manner.
BiZOi (2.3298 g), SrOi (1.1692 g), CaCO~ (1.0009 g) and Cu0 (2.3862 g) were mixed and ground together in an agate mortar for thirty minutes.
15 The powder was placed in an alumina container and the container placed in a furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 12 hours. The power was then turned off and the furnace allowed to cool to a 20 temperature below about 100°C before the container was removed. The black crystalline product was recovered.
Measurement of the Meissner effect showed the powder product to have an onset of 25 superconductivity at about 75 K.
~vnMOr c 7 A compositor of nominal formula Bi~~~Srj~ZCai~2CujOx was prepared in the following 30 manner. eiz03 (4.6596 g), SrOz (2.3924 g), CaCO~
(2.0018 g) and Cu0 (3.1816 g) were mixed and ground together in an agate mortar for thirty minutes. The powder was placed in an alumina container and the container placed in a furnace 35 and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 12 hours. The 13 4'~ 237 power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the container was removed. The black crystalline product was recovered.
5 Measurement of the Meissner effect showed the powder product to have an onset of superconductivity at about 75 K.
10 A compositon of nominal formula BiZSr2CaCu~Ox was prepared in the following manner. Bi~03 (4.6596 g), SrOZ (2.3924 g), CaC03 (1.0009 g) and Cu0 (2.3865 g) were mixed and ground together in an agate mortar for thirty 15 minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
In Example 3A, the pressed pellet was placed on an alumina tray and the tray placed in a 20 furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 8 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the tray was removed. The 25 black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 83 K.
In Example 3B, another pressed pellet 30 was placed on an alumina tray and the tray placed in a furnace and heated in air at a rate of 10°C
per minute to 900°C and then held at 900°C for 8 hours. The furnace was then cooled at the rate of 2°C per minute to a temperature below about 100°C
35 before the tray was removed. The black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 85 K.
A compositon of nominal formula BiSrCaZCu~OX was prepared in the following manner.
Biz03 (2.3298 g), Sr01 (1.1962 g), CaC03 (2.0018 g) and Cu0 (2.3865 g) were mixed and ground 10 together in an agate mortar for thirty minutes.
The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
In Example 4A, the pressed pellet was placed on an alumina tray and the tray placed in a 15 furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 8 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the tray was removed. The 20 black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 75 K.
In Example 4B, another pressed pellet 25 was placed on an alumina tray and the tray placed in a furnace and heated in air at a rate of 10°C
per minute to 900°C and then held at 900°C for 8 hours. The furnace was then cooled at the rate of 2°C per minute to a temperature below about 100°C
30 before the tray was removed. The black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 75 K.
1 3 4 '~ 2 3 7 lU
A compositon of nominal formula BizSrCaCu~O~ was prepared in the following manner.
BiZO~ (2.3298 g). SrOZ (0.5981 g), CaC03 (0.5005 5 g) and Cu0 (1.1933 g) were mixed and ground together in an agate mortar for thirty minutes.
The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
One of the pressed pellets was placed on 10 an alumina tray and the tray placed in a furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 8 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before 15 the tray was removed. The black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 72 K.
A compositon of nominal formula Bi~~2Sr3~ZCa3~ZCu30x was prepared in the following manner. BizO~ (2.3298 g), Sr(N03)z (2.1163 g), 25 CaCO~ (1.0009 g) and Cu0 (1.5910 g) were mixed and ground together in an agate mortar for thirty minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
30 In Example 6A, the pressed pellet was placed on an alumina tray and the tray placed in a furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 30 hours. The power was then turned off and the 35 furnace allowed to cool to a temperature below about 100°C before the tray was removed. The black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of 5 superconductivity at a temperature below 77 K.
This is consistent with the results found in Example 2.
In Example 6B, another pressed pellet was placed on an alumina tray and the tray placed 10 in a furnace and heated in air at a rate of 10°C
per minute to 850°C and then held at 850°C for 12 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the tray was removed. The 15 black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 85 K.
A compositon of nominal formula Bi3~iSr~~~Caj~4Cu30% was prepared in the following manner. BiiO~ (4.6596 g), SrOi (1.1962 g), CaC03 (1.0009 g) and Cu0 (3.1816 g) were mixed and 25 ground together in an agate mortar for thirty minutes. The powder was placed in an alumina container and the container placed in a furnace and heated in air at a rate of 10°C per minute to 850°C and then held at 850°C for 12 hours. The 30 power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the container was removed. The black crystalline product was recovered.
Measurement of the Meissner effect 35 showed the powder product to have an onset of superconductivity at about 70 K.
A compositon of nominal formula BiSrCaZCu~OX was prepared in the following manner.
Biz03 (2.3298 g), Sr01 (1.1962 g), CaC03 (2.0018 g) and Cu0 (2.3865 g) were mixed and ground 10 together in an agate mortar for thirty minutes.
The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
In Example 4A, the pressed pellet was placed on an alumina tray and the tray placed in a 15 furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 8 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the tray was removed. The 20 black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 75 K.
In Example 4B, another pressed pellet 25 was placed on an alumina tray and the tray placed in a furnace and heated in air at a rate of 10°C
per minute to 900°C and then held at 900°C for 8 hours. The furnace was then cooled at the rate of 2°C per minute to a temperature below about 100°C
30 before the tray was removed. The black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 75 K.
1 3 4 '~ 2 3 7 lU
A compositon of nominal formula BizSrCaCu~O~ was prepared in the following manner.
BiZO~ (2.3298 g). SrOZ (0.5981 g), CaC03 (0.5005 5 g) and Cu0 (1.1933 g) were mixed and ground together in an agate mortar for thirty minutes.
The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
One of the pressed pellets was placed on 10 an alumina tray and the tray placed in a furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 8 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before 15 the tray was removed. The black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 72 K.
A compositon of nominal formula Bi~~2Sr3~ZCa3~ZCu30x was prepared in the following manner. BizO~ (2.3298 g), Sr(N03)z (2.1163 g), 25 CaCO~ (1.0009 g) and Cu0 (1.5910 g) were mixed and ground together in an agate mortar for thirty minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
30 In Example 6A, the pressed pellet was placed on an alumina tray and the tray placed in a furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 30 hours. The power was then turned off and the 35 furnace allowed to cool to a temperature below about 100°C before the tray was removed. The black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of 5 superconductivity at a temperature below 77 K.
This is consistent with the results found in Example 2.
In Example 6B, another pressed pellet was placed on an alumina tray and the tray placed 10 in a furnace and heated in air at a rate of 10°C
per minute to 850°C and then held at 850°C for 12 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the tray was removed. The 15 black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 85 K.
A compositon of nominal formula Bi3~iSr~~~Caj~4Cu30% was prepared in the following manner. BiiO~ (4.6596 g), SrOi (1.1962 g), CaC03 (1.0009 g) and Cu0 (3.1816 g) were mixed and 25 ground together in an agate mortar for thirty minutes. The powder was placed in an alumina container and the container placed in a furnace and heated in air at a rate of 10°C per minute to 850°C and then held at 850°C for 12 hours. The 30 power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the container was removed. The black crystalline product was recovered.
Measurement of the Meissner effect 35 showed the powder product to have an onset of superconductivity at about 70 K.
A compositor of nominal formula Bi3~iSr~~aCd9~eCu~Ox was prepared in the following 5 manner. BizOi (4.6596 g), Sr01 (0.5981 g), CaC03 (1.5014 g) and Cu0 (3.1816 g) were mixed and ground together in an agate mortar for thirty minutes. The powder was placed in an alumina container and the container placed in a furnace 10 and heated in air at a rate of 10°C per minute to 850°C and then held at 850°C for 12 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the container was removed. The black crystalline 15 product was recovered.
Measurement of the Meissner effect showed the powder product to have an onset of superconductivity at about 70 K.
A compositor of nominal formula Bi~~ZSr~~2Ca~~zCu30K was prepared in the following manner. BiZ03 (4.6596 g), SrOz (2.3924 g), CaC03 (2.0018 g) and Cu0 (3.1816 g) 25 were mixed and ground together in an agate mortar for thirty minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick. One of the pressed pellets was placed on a gold tray and the tray placed in a 30 furnace and heated in air at a rate of 10°C per minute to 850°C and then held at 850°C for 48 hours. The pellet was then removed from the furnace, quenched in air and the black crystalline product recovered.
~3,~~237 Measurement of the Meissner effect showed the product to have an onset of superconductivity at about 115 K.
A compositon of nominal formula BI~SrZCaCu~OX was prepared in the following manner. BilO~ (4.6596 g), SrOi (2.3924 g), CaCOj (1.0009 g) and Cu0 (2.3865 g) were mixed and 10 ground together in an agate mortar for thirty minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
One of the pressed pellets was placed on 15 a gold tray and the tray placed in a furnace and heated in air at a rate of 10°C per minute to 850°C and then held at 850°C for 48 hours. The pellet was then removed from the furnace, quenched in air and the black crystalline product 20 recovered.
Measurement of the Meissner effect showed the product to have an onset of superconductivity at about 115 K.
A compositon of nominal formula Bi~Sr3CaCu~Ox was prepared in the following manner. BiiO~ (4.6596 g), SrO~ (2.3924 g), CaCO~
(0.6800 g) and Cuo (1.5910 g) were mixed and 30 ground together in an agate mortar for thirty minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
In Example 3A, the pressed pellet was 35 placed on an alumina tray and the tray placed in a furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 8 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the tray was removed. The 5 black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 72 K.
A compositon of nominal formula Bi2SrzCaCujOx was prepared in the following manner. Bii03 (4.6596 g), SrOi (2.3924 g), CaCO~
(1.0009 g) and Cu0 (2.3865 g) were mixed and 15 ground together in an agate mortar for thirty minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
One of the pressed pellets was placed on 20 a gold tray and the tray placed in a furnace and heated in air at a rate of 10°C per minute to 875°C and then held at 875°C for 36 hours. The furnance was then cooled at the rate of 1°C per minute to a temperature below about 100°C before 25 the tray was removed.
Plate-like crystals which exhibited cleavage in the basal plane were predominant in the melt. They were mechanically separated and used for further characterization and structure 30 determination. Both flux exclusion and electrical resistivity measurement on the single crystals revealed a sharp superconducting transition at T
of about 95 K.
The supecconducting metal oxide phase of 35 this composition was identified as BiZSr~_~CaLCuiOe~~
1341~23~
where "z" was abut 0.65 and "w" was less than 1 but greater than zero. The structure based on an A-centered orthorhombic cell with a = 5.409 , b ~ 5.414A and c = 30.914A was 5 determined by using single crystal x-ray diffraction data.
The structure was made up of alternating double copper-oxygen sheets and double bismuth-oxygen sheets. There were Cal' and SrZ' 10 rations between the adjacent Cu-O sheets; Sri' rations were also found between the Cu-O and Bi-O
sheets. High resolution transmission electron microscopy studies showed that the b axis is actually 27.07 ~, an increase of a factor of five 15 over the subcell dimension. This superstructure can also be observed by x-ray diffraction on single crystals but twinning can make it appear that the superstructure is along both the a and b axes.
20 It should be understood that when "z" in the formula for the metal oxide superconducting phase is anywhere from about 0.1 to 0.9, "a" and "b" are both about 5.4A and "c" is about 31A, whi le ~C , B and ~ ( the angles associated wi th the unit cell as known to those skilled in the art) are about 90°. Furthermore, as shown in this example, one or two of the subcell dimensions (a or b or c) can be multiplied by an integer of from about 2 to about 10 to obtain a cell exhibiting 30 the superstructure of the superconducting phase of this invention.
Measurement of the Meissner effect showed the powder product to have an onset of superconductivity at about 70 K.
A compositor of nominal formula Bi~~ZSr~~2Ca~~zCu30K was prepared in the following manner. BiZ03 (4.6596 g), SrOz (2.3924 g), CaC03 (2.0018 g) and Cu0 (3.1816 g) 25 were mixed and ground together in an agate mortar for thirty minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick. One of the pressed pellets was placed on a gold tray and the tray placed in a 30 furnace and heated in air at a rate of 10°C per minute to 850°C and then held at 850°C for 48 hours. The pellet was then removed from the furnace, quenched in air and the black crystalline product recovered.
~3,~~237 Measurement of the Meissner effect showed the product to have an onset of superconductivity at about 115 K.
A compositon of nominal formula BI~SrZCaCu~OX was prepared in the following manner. BilO~ (4.6596 g), SrOi (2.3924 g), CaCOj (1.0009 g) and Cu0 (2.3865 g) were mixed and 10 ground together in an agate mortar for thirty minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
One of the pressed pellets was placed on 15 a gold tray and the tray placed in a furnace and heated in air at a rate of 10°C per minute to 850°C and then held at 850°C for 48 hours. The pellet was then removed from the furnace, quenched in air and the black crystalline product 20 recovered.
Measurement of the Meissner effect showed the product to have an onset of superconductivity at about 115 K.
A compositon of nominal formula Bi~Sr3CaCu~Ox was prepared in the following manner. BiiO~ (4.6596 g), SrO~ (2.3924 g), CaCO~
(0.6800 g) and Cuo (1.5910 g) were mixed and 30 ground together in an agate mortar for thirty minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
In Example 3A, the pressed pellet was 35 placed on an alumina tray and the tray placed in a furnace and heated in air at a rate of 10°C per minute to 800°C and then held at 800°C for 8 hours. The power was then turned off and the furnace allowed to cool to a temperature below about 100°C before the tray was removed. The 5 black crystalline product was recovered.
Measurement of the Meissner effect showed the pellet to have an onset of superconductivity at about 72 K.
A compositon of nominal formula Bi2SrzCaCujOx was prepared in the following manner. Bii03 (4.6596 g), SrOi (2.3924 g), CaCO~
(1.0009 g) and Cu0 (2.3865 g) were mixed and 15 ground together in an agate mortar for thirty minutes. The powder mixture was used to press 10 pellets, each 10 mm in diameter and about 2 mm thick.
One of the pressed pellets was placed on 20 a gold tray and the tray placed in a furnace and heated in air at a rate of 10°C per minute to 875°C and then held at 875°C for 36 hours. The furnance was then cooled at the rate of 1°C per minute to a temperature below about 100°C before 25 the tray was removed.
Plate-like crystals which exhibited cleavage in the basal plane were predominant in the melt. They were mechanically separated and used for further characterization and structure 30 determination. Both flux exclusion and electrical resistivity measurement on the single crystals revealed a sharp superconducting transition at T
of about 95 K.
The supecconducting metal oxide phase of 35 this composition was identified as BiZSr~_~CaLCuiOe~~
1341~23~
where "z" was abut 0.65 and "w" was less than 1 but greater than zero. The structure based on an A-centered orthorhombic cell with a = 5.409 , b ~ 5.414A and c = 30.914A was 5 determined by using single crystal x-ray diffraction data.
The structure was made up of alternating double copper-oxygen sheets and double bismuth-oxygen sheets. There were Cal' and SrZ' 10 rations between the adjacent Cu-O sheets; Sri' rations were also found between the Cu-O and Bi-O
sheets. High resolution transmission electron microscopy studies showed that the b axis is actually 27.07 ~, an increase of a factor of five 15 over the subcell dimension. This superstructure can also be observed by x-ray diffraction on single crystals but twinning can make it appear that the superstructure is along both the a and b axes.
20 It should be understood that when "z" in the formula for the metal oxide superconducting phase is anywhere from about 0.1 to 0.9, "a" and "b" are both about 5.4A and "c" is about 31A, whi le ~C , B and ~ ( the angles associated wi th the unit cell as known to those skilled in the art) are about 90°. Furthermore, as shown in this example, one or two of the subcell dimensions (a or b or c) can be multiplied by an integer of from about 2 to about 10 to obtain a cell exhibiting 30 the superstructure of the superconducting phase of this invention.
Claims (6)
1. A superconducting metal oxide phase of the formula Bi2Sr3-z Ca z Cu2O8+w and lattice parameters a = 5.4.ANG., b = 5.4.ANG. and c = 31.ANG. based on an A centered orthorhombic unit cell, wherein z is a value from about 0.1 to about 0.9; and w is a value greater than zero and less than 1.
2. A superconducting phase as defined in Claim 1 wherein z is from about 0.4 to about 0.8.
3. A superconducting phase as defined in Claim 1 wherein z is about 0.65 and w is a value greater than zero and less than 1.
4. A superconducting metal oxide phase of the formula Bi2Sr3-z Ca z Cu2O8+w wherein z is a value from about 0.1 to about 0.9 and w is a value greater than zero and less than 1.
5. A superconducting metal oxide phase as in Claim 4 wherein z is from about 0.4 to about 0.8.
6. A superconducting metal oxide phase as in Claim 4 wherein z is 0.6 to 0.7 and having a structure based on an A-centered orthorhombic cell with a = 5.409.ANG., b = 5.414.ANG.
and c = 30.914 .ANG..
and c = 30.914 .ANG..
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US15310788A | 1988-02-08 | 1988-02-08 | |
| US153,107 | 1988-02-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1341237C true CA1341237C (en) | 2001-05-22 |
Family
ID=22545802
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000590128A Expired - Fee Related CA1341237C (en) | 1988-02-08 | 1989-02-03 | Superconducting metal oxide compositions and process for manufacture |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JP2850310B2 (en) |
| KR (1) | KR970000482B1 (en) |
| AU (1) | AU617765B2 (en) |
| CA (1) | CA1341237C (en) |
| DK (1) | DK172938B1 (en) |
| HU (1) | HU217018B (en) |
| NO (1) | NO180043C (en) |
| RU (1) | RU2056068C1 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ATE115104T1 (en) * | 1988-02-05 | 1994-12-15 | Hoechst Ag | SUPERCONDUCTOR AND PROCESS FOR ITS MANUFACTURE. |
| JPH01212227A (en) * | 1988-02-17 | 1989-08-25 | Nippon Telegr & Teleph Corp <Ntt> | Oxide superconducting material |
| DE4108869A1 (en) * | 1991-03-19 | 1992-09-24 | Hoechst Ag | METHOD FOR PRODUCING A SUPRAL-CONDUCTIVE MATERIAL CONTAINING BISMUT |
| RU2460175C1 (en) * | 2011-05-12 | 2012-08-27 | Учреждение Российской академии наук Институт металлургии и материаловедения им. А.А. Байкова РАН | Superconducting composite material based on hts compounds and method of producing said material |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2506892B2 (en) | 1988-02-05 | 1996-06-12 | 松下電器産業株式会社 | Oxide superconducting material |
| JP2629771B2 (en) | 1988-02-05 | 1997-07-16 | 松下電器産業株式会社 | Oxide superconducting material |
| US5181481A (en) * | 1991-03-25 | 1993-01-26 | Foster Wheeler Energy Corporation | Fluidized bed combustion system and method having multiple furnace sections |
| JPH0643268A (en) * | 1992-07-27 | 1994-02-18 | Casio Comput Co Ltd | Stopwatch device |
-
1989
- 1989-02-03 HU HU891437A patent/HU217018B/en not_active IP Right Cessation
- 1989-02-03 RU SU894830651A patent/RU2056068C1/en not_active IP Right Cessation
- 1989-02-03 KR KR1019890701845A patent/KR970000482B1/en not_active Expired - Fee Related
- 1989-02-03 JP JP1502391A patent/JP2850310B2/en not_active Expired - Fee Related
- 1989-02-03 CA CA000590128A patent/CA1341237C/en not_active Expired - Fee Related
- 1989-02-03 AU AU30689/89A patent/AU617765B2/en not_active Ceased
-
1990
- 1990-07-13 NO NO903160A patent/NO180043C/en not_active IP Right Cessation
- 1990-08-07 DK DK199001881A patent/DK172938B1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| NO903160D0 (en) | 1990-07-13 |
| DK188190A (en) | 1990-08-07 |
| HUT57939A (en) | 1991-12-30 |
| NO903160L (en) | 1990-07-13 |
| DK188190D0 (en) | 1990-08-07 |
| HU891437D0 (en) | 1991-11-28 |
| HU217018B (en) | 1999-11-29 |
| NO180043C (en) | 1997-02-05 |
| AU617765B2 (en) | 1991-12-05 |
| JP2850310B2 (en) | 1999-01-27 |
| NO180043B (en) | 1996-10-28 |
| RU2056068C1 (en) | 1996-03-10 |
| KR900700390A (en) | 1990-08-13 |
| DK172938B1 (en) | 1999-10-11 |
| AU3068989A (en) | 1989-08-25 |
| KR970000482B1 (en) | 1997-01-13 |
| JPH03502918A (en) | 1991-07-04 |
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