EP1090398A2 - Dopage critique des supraconducteurs a temperature critique elevee pour un laminage de flux et des courants critiques maximaux - Google Patents

Dopage critique des supraconducteurs a temperature critique elevee pour un laminage de flux et des courants critiques maximaux

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Publication number
EP1090398A2
EP1090398A2 EP99931620A EP99931620A EP1090398A2 EP 1090398 A2 EP1090398 A2 EP 1090398A2 EP 99931620 A EP99931620 A EP 99931620A EP 99931620 A EP99931620 A EP 99931620A EP 1090398 A2 EP1090398 A2 EP 1090398A2
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EP
European Patent Office
Prior art keywords
htsc
hole concentration
composition
controlling
temperature
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Withdrawn
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EP99931620A
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German (de)
English (en)
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EP1090398A4 (fr
Inventor
Jeffery Lewis Tallon
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Industrial Research Ltd
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Industrial Research Ltd
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Publication of EP1090398A2 publication Critical patent/EP1090398A2/fr
Publication of EP1090398A4 publication Critical patent/EP1090398A4/fr
Withdrawn legal-status Critical Current

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    • 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

  • the invention comprises a method for preparing a high temperature superconducting cuprate material (HTSC) to maximise the critical current density of the material, in which the doping state or hole concentration of the material is controlled so as to lie at about the point where the normal-state pseudogap reduces to a minimum.
  • HTSC high temperature superconducting cuprate material
  • T c High-T c Superconducting Cuprates
  • T c values alone do not guarantee the utility of these HTSC at 77K or higher temperatures.
  • these applications require large critical current densities, J c , in the presence of a magnetic field.
  • J c critical current densities
  • Such high currents are only achieved if there is strong flux pinning within the individual grains.
  • a simple measure of the flux pinning contribution to J c is the product, Uo ⁇ , of the condensation energy, U 0 , and the superconducting coherence length, ⁇ .
  • H*(T) temperature-dependent irreversibility field
  • H*(T) temperature-dependent irreversibility field
  • HTSC have a fundamentally important feature that their properties vary with the concentration of doped electronic carriers.
  • the carriers are electron holes, referred to in short as holes.
  • the concentration of holes may be altered by chemical substitution or by changing the oxygen concentration.
  • the hole concentration may be increased by substituting a lower valency atom for a higher valency atom or by increasing the oxygen content.
  • the hole concentration, p may be decreased by substituting a higher valency atom for a lower valency atom or by decreasing the oxygen content.
  • the hole concentration is increased from zero by substituting Sr 2+ for the La 3+ .
  • the hole concentration may be decreased by substituting La 3+ for Ba 2+ or by decreasing the oxygen content as in the formula YB2Cu3 ⁇ 7- ⁇ where ⁇ may be increased from 0 to 1.
  • ⁇ 1 this compound in an undoped insulator like La 2 Cu0 .
  • the maximum T c value in this variation with hole concentration is T c>m ⁇ and it occurs at a hole concentration frequently referred to as optimal doping.
  • the hole concentration is less than optimal doping the HTSC material is referred to as underdoped and when it is greater than optimal doping it is referred to as overdoped.
  • Optimal doping then is seen as the key doping state to which other doping states are referred.
  • the usual criterion for optimising superconductivity in HTSC was to maximise T c .
  • the invention comprises a method for preparing a high temperature superconducting cuprate material (HTSC) to maximise the critical current density (J c ) thereof, comprising the step of controlling the doping state or hole concentration of the material to be higher than the doping state or hole concentration of the material that provides a maximum superconducting transition temperature (T c ) to increase the critical current density of the material.
  • HTSC high temperature superconducting cuprate material
  • the invention comprises a high temperature superconducting cuprate material (HTSC) having a doping state or hole concentration higher than the doping state or hole concentration of the material for maximum superconducting transition temperature (T c ) and at about a value where the normal-state pseudogap for the material reduces to a minimum and which maximises the critical current density (J c ) of the material.
  • HTSC high temperature superconducting cuprate material
  • the optimal doping for maximising T c is not the optimal doping for maximising flux pinning, U 0 , ⁇ v 2 or the critical current density J c .
  • the pseudogap is manifested as a reduction in the normal-state entropy and susceptibility which strongly suppresses superconductivity and all measures thereof including T c , condensation energy and superfluid density.
  • the method may include overdoping the HTSC so that the grain boundary regions between individual grains in the HTSC in particular are doped to maximise the critical current density across grain boundaries.
  • grain boundary regions can tend to be underdoped even if the bulk intragranular material is optimally doped or even overdoped (- see Babcock et al (Physica C 227, 183 (1994)).
  • the pseudogap will often be locally present in the grain boundary regions, the effective superconducting order parameter thus locally reduced, and the grains weakly linked. Additionally, impurities tend to accumulate at the grain boundaries.
  • HTSC have a d-wave order parameter which is very sensitive to the presence of impurities T c being rapidly suppressed at a rate dT c /dy that depends strongly on doping state.
  • the order parameter and the condensation energy are all much more rapidly suppressed due to impurity scattering than in the bulk intragranular material. Impurities in underdoped grain boundaries are therefore especially deleterious.
  • the intragranular J c may be high, the intergranular J c may be low due to the underdoped state of the grain boundary regions.
  • the method of the invention may be used in producing HTSC as bulk materials, wires, tapes or other conductor elements, or thick or thin films for example.
  • Figure 1 is a plot for Yo sCao 2Ba2Cu3 ⁇ - ⁇ of the hole concentration dependence of T c , the pseudogap energy E g and the product U 0 ⁇ b where ⁇ a b is the ab-plane coherence length.
  • Figure 2 is a plot of the hole concentration dependence of T c , E g and U 0 for Bi 2 Sr 2 CaCu 2 0 8+s .
  • Figure 3 is a plot of the hole concentration dependence of ⁇ i/ 2 for Yo sCao 2 Ba 2 Cu 3 0 7 .s.
  • Figure 4 is a plot of the p-dependence of the magnetisation (proportional to the critical current) of YBa2Cu3 ⁇ - ⁇ grain aligned in epoxy. Data is shown for different field strengths and temperatures as shown. The parabolic curve is T c plotted as a function of p.
  • the parabolic curve is T c plotted as a function of hole concentration, p.
  • Figure 6 is a plot of the p-dependence of the magnetisation critical current density in 0.2 Tesla at 10K and 20K as well as the irreversibility temperature at 5 Tesla for Yo sCao 2Ba2Cu3 ⁇ - ⁇ grain-aligned in epoxy.
  • the parabolic curve is T c plotted as a function of hole concentration, p.
  • the doping state or hole concentration is controlled or adjusted in producing the HTSC to maximise flux pinning and critical current density, to lie at or near a critical overdoped hole concentration (herein: critical doping) at which the normal-state pseudogap is minimised or disappears, and as a consequence the superconducting condensation energy sharply maximises and the London penetration depth, X L , sharply minimises.
  • critical doping critical overdoped hole concentration
  • the doping state or hole concentration of the HTSC may be controlled or adjusted by cation substitution, or by increasing the oxygen content of the material beyond that which gives maximum Tc, or a combination of both.
  • Cation substitution to achieve critical doping may be by altervalent substitution sucii as substitution of Ca 2+ , Li + , Na + or K + for R 3+ in 123, 247 and 124 materials; Li + , Na + or K + for Ba 2+ in 123, 247 and 124 materials; R 3+ for Ca + in Bi-2212, Tl-2212, Tl- 1212 or Hg- 1212; Pb 2+ for Bi 3+ in Bi-2212 and Bi-2223; and Pb * » + for Tl 3+ in Tl- 1212 and Tl-2212.
  • the compound Tlo sPbo sSr CaCu20 7 for example has a fixed stoichiometric oxygen content so cannot be adjusted to critical doping by changing the oxygen content.
  • preferably 0. 12 ⁇ 0.04 Y is substituted for Ca or 0.12 ⁇ 0.04La for Sr in this compound to achieve critical doping.
  • Other rare earth elements may be utilised in the same way in this and other HTSC compounds, noting that small rare earth elements should preferably be substituted for Ca and the larger rare earth elements preferably for Sr. Combined substitution on both the Sr and Ca sites may of course be utilised. Quite generally Li + substitution in any HTSC material is suitable for increasing the hole concentration of that material.
  • Oxygenation to achieve critical doping may be achieved by conventional annealing in an oxygen-containing atmosphere or by titration using electrochemical means. Achieving the oxygen content required for critical doping in any HTSC may require the use of oxygen pressures in excess of 1 atmosphere or lower annealing temperatures than otherwise conventionally used to form the HTSC. Depending upon density of the HTSC such annealing may take many days to equilibrate and it may be more convenient to use higher oxygen pressures at higher temperatures where the kinetics of oxygen uptake is faster, or a combination of cation substitution with oxygenation such complete oxygenation is not required. The altervalent substitution of cations tends to alter the oxygen content.
  • the HTSC material may be a Bi-Sr-Ca-Cu-O based material such as Bi-2212, which is of nominal composition Bi2Sr2CaCu2 ⁇ 3+ ⁇ where O ⁇ 0.35, or Bi-2223, which is of nominal composition B-2Sr2Ca2Cu3 ⁇ + ⁇ where 0 ⁇ 0.35 (where Bi may be partially substituted by Pb, Hg, Re, Os, Ru, Tl, V, Cr, Zr, Nb, Mo, Hf, Ta, W, Co or Sm, Sr may be partially substituted by Ba or a larger lanthanide rare earth element, and Ca may be partially substituted by Y or a lanthanide rare earth element for example, and in these chemical formulae it is also recognised in the art that small variations in stoichiometry are common in such oxide materials).
  • Bi-2212 is of nominal composition Bi2Sr2CaCu2 ⁇ 3+ ⁇ where O ⁇ 0.35, or Bi-2223, which is of nominal composition B-2Sr2Ca2Cu3 ⁇ +
  • Bi-2212 and Bi-2223 Bi is commonly partially replaced by Pb, such that Bi may be Bi ⁇ - z Pb z where 0 ⁇ z ⁇ 0.3.
  • Especially preferred compounds include Bi2+ e Sr2CaC 2 ⁇ g + ⁇ Bi2+ x +eSr2- x -yCa ⁇ +y C 2 0 8+ ⁇ ) Bi2+e r2Ca2Cu3 ⁇ 10 + ⁇ and
  • Bi-2212 and Bi-2223 may be varied by cation substitution (which increases the hole concentration p) R for Ca in Bi-2212 where R is Y or any lanthanide rare earth element, or Bi in Bi-2212 and Bi-2223 for example or by varying ⁇ .
  • ⁇ may be fixed by annealing the HTSC at about (570 ⁇ 15)°C in an oxygen partial pressure of 0. 1 bar or at a combination of temperature and oxygen partial pressure giving the same value of ⁇ . Only a small ⁇ variability is possible in Bi-2223, which allows only minor changes in hole concentration.
  • Bi-2212 may be substantially overdoped by full oxygenation to p «0.22 or 0.225 whereas B-2223 may only be doped to p «0. 17 or at most 0.18.
  • Bi-2223 material may alternatively be prepared to incorporate intergrowths of Bi-2212 in Bi-2223. Intergrowths of Bi-2212 in Bi-2223 increase the doping state of the latter. Such hole-doping intergrowths can be introduced by substituting very small amounts ( ⁇ 1% and preferably ⁇ 0. 1%) of Y or a lanthanide rare-earth element on the Ca site.
  • Bii sPbo 3Sr ⁇ 9Ca2Cu3 ⁇ o+ may incorporate intergrowths of Bii sPbo 3Sr ⁇ Bii 7sPbo.35Sr ⁇ gCa2Cu3 ⁇ o+ ⁇ may incorporate intergrowths of Bii 7sPbo 3sSr ⁇ gCaCu Os+ ⁇ "
  • Bii 3 Pbo 3 4 Sn gCai 99CU3 o 4 O ⁇ o+ ⁇ may incorporate intergrowths of Bii 73Pbo 3 Sr ⁇ 9CaCu2 ⁇ s+ ⁇ ;
  • Bii 88Pb 0 23Sri 96Ca ⁇ 95Cu 98 ⁇ o+ ⁇ may incorporate intergrowths of composition Bii ⁇ Pbo 23Sr ⁇ 96CaCu2 ⁇ s+ ⁇ ; and Bii 8 4 Pbo 28Sr ⁇ 93Ca ⁇ gsC ⁇ g ⁇ Oio+ ⁇ may incorporate intergrowths of composition Bii 8 4 Pbo 2 sSr ⁇ 93CaCu ⁇ s+ .
  • the HTSC may be an R-Ba-Ca-CuO based HTSC such as the material R- 123, which is of nominal composition RBa2Cu3 ⁇ 7 - ⁇ where R is Y or a lanthanide rare earth element or a combination thereof and O ⁇ 0.5, (and R may be partially substituted by Ca, and Ba may be partially substituted by Sr, La or Nd for example, and it is also recognised in the art that small variations in stoichiometry are common in such oxide materials).
  • Critical doping is preferably achieved by oxygenation to ⁇ 0.05, optionally combined with cation substitution, of Ca, Li, Na or K for R, or Li, Na, or K for Ba for example.
  • R is a larger rare earth element
  • small amounts of Ca are substituted for R so to achieve critical doping.
  • Preferred compounds are Ri.
  • ⁇ is as small as possible commensurate with critical doping.
  • x typically x ⁇ 0.1 such that critical doping is achieved for ⁇ O.10. It is more preferable that x ⁇ 0.05 and ⁇ 0.03.
  • the HTSC may be R-247, which is of nominal composition R2 -x Ca ⁇ Ba4Cu7 ⁇ i5. s where R is Y or a lanthanide rare earth element or a combination thereof and O ⁇ 0.5 (and R may be partially substituted by Ca, and Ba may be partially substituted by Sr, La or Nd for example, and it is also recognised in the art that small variations in stoichiometry are common in such oxide materials).
  • Critical doping is preferably achieved by oxygenation to ⁇ 0.05, optionally combined with cation substitution, of Ca, Li, Na or K for R, or Li, Na, or K for Ba for example.
  • Preferred compounds are R2- x Ca ⁇ Ba 4 Cu 7 Oi5- ⁇ where O ⁇ x ⁇ O.35 and 0 ⁇ 0.5 and R2- ⁇ Li x Ba4Cu 7 Oi5- ⁇ where 0 ⁇ x ⁇ 0.35 and 0 ⁇ 0.5 and wherein x and ⁇ are jointly adjusted so that the copper oxygen planes are critically doped as described above.
  • ⁇ is as small as possible commensurate with critical doping.
  • x typically x ⁇ 0.1 such that critical doping is achieved for ⁇ 0.10. It is more preferable that x ⁇ 0.05 and ⁇ 0.03.
  • the HTSC may be R- 124, which is of nominal composition RBa Cu 4 Os where R is Y or a lanthanide rare earth element and 0 ⁇ 0.35 (and R may be partially substituted by Ca and Ba may be partially substituted by Sr, La or Nd for example, and it is also recognised in the art that small variations in stoichiometry are common in such oxide materials).
  • Critical doping is achieved by cation substitution, of Ca, Li, Na or K for R, or Li, Na, or K for Ba for example.
  • Preferred compounds are R ⁇ - x Ca ⁇ Ba Cu 4 ⁇ 8 and R ⁇ .xLixBa 2 Cu 4 08 where 0 ⁇ x ⁇ 0.35. Because 124 is typically even more underdoped relative to the equivalent 247 and 123 materials a higher level of cation substitution is required than in the equivalent 247 and 123 materials.
  • a small rare earth such as Tl or Lu is desirable to achieve the higher Ca content required.
  • the HTSC material may be a Tl-Sr-Ca-Cu-O based material such as Tl-1201, which is of nominal composition TlSr2CuOs+6, or Tl- 1212, which is of nominal composition TlSr2CaCu2 ⁇ 7+ ⁇ , or Tl-1223 which is of nominal composition TlSr Ca 2 Cu 3 ⁇ 8+ ⁇ (and where Tl may be partially substituted by Pb, Sr may be partially substituted by La or Ba, and Ca may be partially substituted by R, for example, and in these chemical formulae it is also recognised in the art that small variations in stoichiometry are common in such oxide materials).
  • Tl-1201 which is of nominal composition TlSr2CuOs+6, or Tl- 1212, which is of nominal composition TlSr2CaCu2 ⁇ 7+ ⁇
  • Tl-1223 which is of nominal composition TlSr Ca 2 Cu 3 ⁇ 8+ ⁇
  • Tl may be partially substituted by Pb
  • Sr may be partially
  • the HTSC may also be a mercury-based HTSC such as Hg- 1212, which is of nominal composition HgBa2CaCu2 ⁇ 6+ ⁇ , or Hg- 1223 which is of nominal composition HgBa2Ca2Cu3 ⁇ s+ (and where Hg may be partially substituted by Tl, Bi, Pb or Cd, and Ba may be partially substituted by Sr for example, and in these chemical formulae it is also recognised in the art that small variations in stoichiometry are common in such oxide materials).
  • Hg- 1212 which is of nominal composition HgBa2CaCu2 ⁇ 6+ ⁇
  • Hg- 1223 which is of nominal composition HgBa2Ca2Cu3 ⁇ s+
  • Hg may be partially substituted by Tl, Bi, Pb or Cd
  • Ba may be partially substituted by Sr for example
  • the critically-adjusted doping state may be quantitatively defined by the HTSC having an overdoped T c with the room temperature thermoelectric power Q(T RT ) in units of ⁇ V/K satisfying -4 ⁇ Q(TRT) ⁇ - 1 and more preferably -3 ⁇ Q(T RT ) ⁇ -2 where 280 K ⁇ T RT ⁇ 300 K.
  • the critically-adjusted doping state may be quantitatively defined by the HTSC having an overdoped T with the normal-state constant-volume resistivity remaining linear in temperature from 250K down to less than 20K above T c .
  • the normal-state constant-volume resistivity remains linear in temperature from 500K down to less than 20K above T c .
  • the critically-adjusted doping state may be quantitatively defined by the HTSC having an overdoped T c with the temperature derivative of the normal-state constant- volume resistivity remaining constant within ⁇ 5% when the temperature is reduced from 250K down to less than 2 OK above T c and, more preferably, when the temperature is reduced from 500K down to less than 2 OK above T c
  • the critically-adjusted doping state may be defined by annealing the HTSC in an oxygen-containing atmosphere previously determined to result in a critically overdoped T c with either T c , thermoelectric power or the normal-state resistivity lying within the above noted preferred margins or with the pseudogap having been critically suppressed to zero as determined by heat capacity, NMR spectroscopy, susceptibility or other means.
  • Bi1.9Pbo.2Sr1 CaCu 2 ⁇ 8+ ⁇ may be annealed at 570°C in a mixture of 10% oxygen and 90% nitrogen gases (an oxygen partial pressure of 0.
  • the doping state in any HTSC may be defined by Raman measurement of the frequency of a particular phonon mode, the desired frequency having been previously ascertained from a correlation with one of hole concentration, thermoelectric power, resistivity, oxygen annealing or T c value.
  • One such mode is the 630 cm 2 A ⁇ g mode.
  • the bulk material may be overdoped so that the grain boundary regions between individual grains in the HTSC are doped to maximise critical current density in the grain boundary regions of the HTSC in particular, even at some sacrifice maximal intragranular critical current density in order to maximise intergranular currents.
  • cation solubility and oxygen activity will be different in grain boundaries. If for example Ca 2+ substitution is preferred in grain boundaries relative to the bulk then there is some prospect of critically doping both the grain boundaries and the bulk simultaneously. If Ca 2+ substitution is preferred in the bulk relative to the grain boundaries then a compromise, as discussed above, may be necessary.
  • the method of the invention may be used in forming HTS materials into long-length flexible wires or tapes by the technique known in the art as powder-in- tube processing. This technique is especially used in the case of Bi-2212 or Bi-2223 materials. Powders of these materials or precursors to these materials are packed into a metallic tube, often made of silver metal or silver alloy, then by a process of deformation and heat treatment the tube is drawn out into a long wire and the oxide reacted to form a highly textured Bi-2223, for example, HTSC core. The wire may be rebundled once or many times to form a multifilamentary wire.
  • Metallic alloy precursors may also be used to form such long wires and by heat treatment and deformation the metallic alloys are converted to oxides and reacted to form a highly- textured Bi-2223, for example, HTSC core.
  • Other techniques such as coating or melt processing may also be used to form long-length wires or tapes.
  • the materials may also be formed as thin films using any process as is known in the art or as bulk melt-processed single-domain or near-single-domain monolithic bodies.
  • T c ,max is the maximum in the approximately parabolic hole- concentration dependence of T c (p).
  • the pseudogap energy, E g was determined from fitting the temperature dependence of the entropy and values were confirmed by fitting the temperature dependent 8 Y NMR Knight shifts.
  • the open triangles are the values of E g determined for Yo sCao 2Ba2Cu3 ⁇ 7 - ⁇ from NMR measurements and these show that the two methods give comparable results for E g .
  • U 0 passes through an unexpectedly sharp maximum in the lightly overdoped region where E g becomes zero. Again U 0 approximately doubles on progressing from optimal doping to critical doping. This data for Bi-2212 is confirmed by direct heat capacity measurements.
  • Figure 4 shows a plot of the magnetisation in units of emu as a function of p for measurements at 0.2T, 0.5T and 2T as well as at temperatures of 20K, 40K and 60K.
  • the parabolic curve of T c as a function of p is also plotted to show that the sharp maximum occurs in the lightly overdoped state.
  • the criticality of doping is very evident in this plot, especially at low temperature.
  • H* is also seen to pass through a sharp maximum but the maximum occurs beyond critical doping because H* is governed by the product ⁇ a b 2 . ⁇ c 2 where ⁇ a b is the in-plane penetration depth and ⁇ c is the c-axis penetration depth.
  • ⁇ a b 2 is proportional to the superfluid density which QC U 0 and hence passes through a sharp maximum at critical doping.
  • ⁇ c oc p c the c-axis resistivity which monotonically decreases with doping, p.
  • Samples of Tl 0 .5Pbo.5Sr2Ca ⁇ - x Y x Cu2 ⁇ 7 and 0.05, 0.1, 0.2, 0.3 and 0.4, and y 0, 0.05, 0.1, 0.2, 0.25, 0.3 and 0.4 were synthesized by solid-state reaction of pellets in oxygen at 1060°C of a stoichiometric mixture of the oxides of Tl, Pb, Y, La and Cu and the carbonates of Ca and Sr.
  • the precursor materials were first reacted without the TI2O3 which was then added for a further reaction at 1060°C. The reacted material was ground and resintered under the same conditions.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)

Abstract

L'invention concerne un procédé permettant de maximiser l'intensité du courant critique (Jc) de matériaux aux cuprates (HTSC) qui consiste à gérer le niveau de dopage ou la concentration en trous des matériaux pour qu'il soit supérieur au niveau de dopage ou de concentration en trous du matériau à l'état où il assure une température de transition supraconductrice maximale (Tc) et pour qu'il se situe aux environs d'une valeur telle que le pseudo-intervalle à l'état normal soit ramené à un minimum. En l'occurrence, Jc est maximum pour une concentration en trous p≈0,19. Font aussi l'objet de cette invention les composés HTSC.
EP99931620A 1998-06-18 1999-06-18 Dopage critique des supraconducteurs a temperature critique elevee pour un laminage de flux et des courants critiques maximaux Withdrawn EP1090398A4 (fr)

Applications Claiming Priority (5)

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NZ33072898 1998-06-18
NZ33072898 1998-06-18
NZ33397199 1999-01-29
NZ33397199 1999-01-29
PCT/NZ1999/000095 WO1999066541A2 (fr) 1998-06-18 1999-06-18 Dopage critique des supraconducteurs a temperature critique elevee pour un laminage de flux et des courants critiques maximaux

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Publication number Priority date Publication date Assignee Title
EP1006594A1 (fr) * 1998-12-03 2000-06-07 Jochen Dieter Prof. Dr. Mannhart Supraconducteur à densité de courant amélioré et procédé de sa fabrication
CN103400932B (zh) * 2008-08-29 2016-08-10 Lg化学株式会社 新型热电转换材料及其制备方法，以及使用该新型热电转换材料的热电转换元件

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989006222A1 (fr) * 1987-12-30 1989-07-13 Unisearch Limited Procede ameliore de production de supraconducteurs en ceramique
US5619141A (en) * 1992-04-03 1997-04-08 Tallon; Jeffery L. Thermopower mapping of superconducting cuprates

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH04114920A (ja) * 1990-08-28 1992-04-15 Ind Technol Res Inst 超伝導金属酸化物Ｔｌ―Ｐｂ，Ｌｎ―Ｓｒ―Ｃｕ―Ｏ組成物
US5919735A (en) * 1994-11-04 1999-07-06 Agency Of Industrial Science And Technology High temperature superconductor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989006222A1 (fr) * 1987-12-30 1989-07-13 Unisearch Limited Procede ameliore de production de supraconducteurs en ceramique
US5619141A (en) * 1992-04-03 1997-04-08 Tallon; Jeffery L. Thermopower mapping of superconducting cuprates

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
FUJINAMI K ET AL: "Effect of overdoping on the irreversibility field and critical current density of the HgBa2Ca2Cu3O8+delta superconductor" PHYSICA C, NORTH-HOLLAND PUBLISHING, AMSTERDAM, NL, vol. 307, no. 3-4, October 1998 (1998-10), pages 202-208, XP004149995 ISSN: 0921-4534 *
J.L. TALLON, G.V.M. WILLIAMS, N.E. FLOWER, C. BERNHARD: "Phase Separation, Pseudogap an Impurity Scattering in the HTS Cuprates" PHYSICA C, vol. 282-287, 1997, pages 236-239, XP004110983 *
J.L. TALLON: "Thermoelectric Power of High-Tc Cuprates" PROCEEDINGS OF 10TH ANNIVERSARY, HTS WORKSHOP ON PHYSICS, MATERIALS AND APPLICATIONS, no. ISBN981-02-2715-9, 1996, pages 292-295, XP009110712 *
J.W. RADCLIFFE ET AL.: "Magnetoresistance and dc magnetic susceptibility of Y0.9Ca0.1Ba2Cu3O7-[delta]" PHYSICA C, vol. 235-240, 1994, pages 1415-1416, *
RAVEAU B ET AL: "Control of oxygen stoichiometry and creation of nuclear tracks, two important issues for optimization of superconductivity in layered copper oxides" PHYSICS AND MATERIALS SCIENCE OF HIGH TEMPERATURE SUPERCONDUCTORS II. PROCEEDINGS OF THE NATO ADVANCED STUDY INSTITUTE KLUWER ACADEMIC PUBLISHERS DORDRECHT, NETHERLANDS, 1992, pages 167-198, XP009077838 ISBN: 0-7923-1619-3 *
See also references of WO9966541A2 *

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EP1090398A4 (fr) 2007-05-02
WO1999066541A3 (fr) 2000-04-20
WO1999066541A2 (fr) 1999-12-23
AU4806499A (en) 2000-01-05
JP2002518287A (ja) 2002-06-25

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