JP2002518287A - Critical doping in high-Tc superconductors to obtain maximum flux spinning and critical current - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductor having a high Tc by performing pinning of a magnetic flux and critical doping for maximizing a critical current density. A method for maximizing a critical current density of a high-temperature superconducting cuprate material (HTSC), wherein the method controls a doping state or a hole concentration to maximize a superconducting transition temperature (Jc). Increasing the doping state or hole concentration of the material to be formed and adopting a value that reduces the pseudo gap of the property state to a minimum value. Jc is maximized when the hole concentration is approximately 0.19. HTSC compounds have also been claimed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

The present invention includes a method of manufacturing a high temperature superconducting cuprate material (HTSC) that maximizes the critical current density of the cuprate material, wherein the standard state pseudogap (pseudogap) is minimized. The doping state or hole concentration of the material is adjusted so as to be near the point.

[0002]

[Prior art]

 Many high-Tc superconducting cuprates (HTSC) are at the temperature at which liquid nitrogen boils,
It is known to have a superconducting transition temperature Tc of over. Therefore, these
From electricity, distribution (distribution), conversion and control to high-field magnets, motors,
Potentially large numbers, ranging from channel, telecommunications and electronics
With the use of. The value of Tc is, for example, YBa_TwoCu_ThreeO_{7- δ}About 93K, such as Bi_TwoSr _Two CaCu_TwoO₈About 95K, for example Bi_TwoSr_TwoCa_TwoCu_ThreeO_TenAbout 109K, for example TlBa_TwoC
a_TwoCu_ThreeO_TenAbout 120K or HgBa_TwoCa_TwoCu_ThreeO_TenAbout 134K
You. For many of these applications, such a Tc value alone would be 77K or higher
The utility of these HTSCs at different temperatures is not guaranteed. These uses are often
It requires a large critical current density Jc in the presence of a magnetic field. The HTSC particles are crystallographically
Even when thinly aligned or organized, but also generally achieved in thin films
Sintered together so that the weak bonds between the particles were eliminated.
However, a high critical current in the presence of a magnetic field is not guaranteed. Strong within the individual particles
Only when flux pinning is present is this high
A current is realized. A simple measure of the contribution of the flux spinning to Jc is
, Condensation energy U₀And the superconducting coherence length ξ, U₀ξ. HTSC material
Of the inherent ability of the material to maintain a high critical current in the presence of a magnetic field
The measure is the temperature dependent irreversibility field, H * (T). Over H *
For a given magnetic field, the magnetization is reversible and therefore dissipative, while the magnetic field is less than H *.
It is irreversible, ie substantially non-dissipative, to the field. For a given temperature
Therefore, when H * is large, the critical current density for the magnetic field H <H * at the temperature is high.
Could be something. Many models for the irreversible magnetic field are H * ∝λ_L ^-2To
Where λ_LIs the in-plane London penetration depth. Therefore, λ_LIs minimized (λ_L ^-2To
H * can be maximized.

[0003]

[Problems to be solved by the invention]

 HTSC has the fundamental property that its properties vary with the concentration of the doped electron carrier.
It has important features. These carriers are electron holes, also called holes for short.
You. The hole concentration is determined by chemical substitution or by changing the oxygen concentration.
More can be changed. In general, replace higher valence atoms with lower valence atoms
Or increase the oxygen concentration to increase the hole concentration
can do. By replacing low-valent atoms with higher-valent atoms,
Can reduce the hole concentration p by reducing the oxygen concentration. Scratch
The undoped (undoped) insulator La_TwoCuO_FourThen, the hall
The concentration is La³⁺, Sr²⁺, The value increases from zero. YBa_TwoCu_ThreeO₇
Then, the hole concentration is Ba²⁺To La³⁺Or by replacing the formula: YB_TwoCu_ThreeO _{7- δ} (Where δ can be increased from 0 to 1).
By reducing it, it can be lowered. Undoped if δ = 1
This compound in the insulator is La_TwoCuO_FourIs the same as The hole concentration is
By increasing from an uninsulated state, the HTSC can consequently superconduct at low temperatures.
It becomes conductive. This (low) threshold hole concentration is, for example, about p = 0.05.

If the hole concentration is very high and increases above the upper threshold, the HTSC material becomes a non-superconducting metal, even at the lowest temperatures. This upper threshold is about p = 0.27
It is. Between these lower and upper thresholds, Tc is from about zero at the lower threshold to about p =
Increases smoothly to a maximum of 0.16 and then smoothly decreases to zero at the upper threshold. The maximum value of Tc in this variation with hole concentration is Tc, max, and this occurs at a hole concentration often referred to as optimal doping. This variation of Tc with hole concentration is approximated by Tc (p) = Tc, max [1-82.6 (p-0.16 ² )],
With a substantially parabolic change, as described above, Tc is maximized at p ≒ 0.16. For optimal doping, the room temperature thermoelectric power has a value of Q (290K) = + 2 μV / K (Tallon et al., US Pat. No. 5,619,141, which is a reference of the present invention). If the hole concentration is less than optimal doping, the HTSC material is said to be undoped, and if the hole concentration is greater than optimal doping, the material is said to be overdoped. Thus, optimal doping is considered to be an important doping state when referring to other doping states. Prior to the present invention, HTSC
A general criterion for optimizing the superconductivity in was to maximize Tc.

[0005]

[Means for Solving the Problems]

In one broad aspect, the invention includes a method of manufacturing a high-temperature superconducting cuprate material (HTSC) to maximize the critical current density (Jc) of the high-temperature superconducting cuprate material, The method comprises controlling the doping state of the material or its hole concentration to be higher than the doping state of the material or its hole concentration, which gives the maximum superconducting transition temperature (Tc), and the critical current density of the material. Including the step of increasing According to another aspect in a broad sense, the present invention relates to a high-temperature superconducting cuprate material (HTSC)
Wherein the HTSC is higher than the doping state or hole concentration of the material to obtain a maximum superconducting transition temperature (Tc), and the standard state pseudo gap for the material is reduced to a minimum value, and It has a doping state or a hole concentration near a value at which the critical current density (Jc) is maximized.

Surprisingly, we have found that the optimal doping to maximize Tc is the optimal doping to maximize flux spinning, U ₀ , λ _L ^-2 or the critical current density Jc. Not found. We use Jc, flux spinning, U ₀ ,
λ _L ^-2 is at a doping state or hole concentration higher than the doping state or hole concentration that maximizes Tc, i.e., the standard state pseudogap
Was found to be maximum near the point where decreases to a minimum, particularly near the point where the hole concentration is 0.18 ≦ p ≦ 0.20, and most specifically near p = 0.19 or p = 0.19 ± 0.005. We attribute this to the existence of a correlation state across the underdoped and slightly overdoped regions. The correlation state is
Reduce the weight of low-energy spectra in quasiparticle excitation spectra. This reduction in spectral weight is referred to as the pseudogap described above, and is often incorrectly referred to as the spin gap. This pseudogap manifests itself as a decrease in normal state entropy and susceptibility. The disturbance susceptibility significantly suppresses superconductivity, and all its measures include Tc, condensation energy and superfluid density. The pseudo gap energy Eg is the
The standard state temperature dependence of (Knight shift), Ks (T), is calculated by the formula: Ks (T) = K ₀ [1-tanh ² (Eg / 2kT
) + Kc, which can be determined where Kc is the chemical shift. Eg also describes the standard state temperature dependence of entropy, S (T), by the formula: S (T) / T = g ₀ [ta
nh ² (Eg / 2kT)]. Here, g ₀ is a constant.

Typically, Eg has been found to decrease with increasing hole concentration p. More sophisticated means for determining Eg are known (Tallon et al., J. Phys. Chem.
Solids, 1998, 59: 2145, which is the reference of the present invention), but the value of Eg thus determined still decreases approximately linearly with increasing hole concentration. More importantly, the value of the Eg still decreases to zero at about the same value as p = 0.19 ± 0.005.

[0008] The method can overdope the HTSC, especially the grain boundary region between individual grains in the HTSC to maximize the critical current density across the grain boundary. Such grain boundary regions tend to be underdoped, even when most intragranular materials are optimally doped or overdoped (Babcock et al., Physica, 1994, C227: 183). The pseudo gap is often located locally in the grain boundary region, locally reducing the effective superconducting order parameter and weakly binding the particles. Further, impurities tend to be accumulated at these grain boundaries. HTSC has a d-wave order parameter, which is extremely sensitive to the presence of impurities, and Tc is rapidly suppressed at a rate highly dependent on the doping state: dTc / dy You. In the under-doped grain boundary region Tc, the order parameters and condensation energy are all suppressed more rapidly than in most of the intragranular materials due to large impurity variations. Impurities at the underdoped grain boundaries are therefore particularly harmful. Thus, the intragranular Jc may be high, but the intergranular Jc may be low due to the underdoped state of the grain boundary region. The method of the present invention can be used in the manufacture of HTSC, as a bulk material, wire, tape or other conductive element, or as a thick or thin film.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION

In the method of the present invention, in producing the HTSC, the doping state or the hole concentration is adjusted to maximize the flux spinning and the critical current density, and the critical over-doped hole concentration (here, critical doping) or its vicinity. At this concentration, the normal state pseudogap is minimized or vanished, and consequently its superconducting condensation energy sharply maximizes, and the London penetration depth, λ _L, is sharply minimized. The critical hole concentration can be determined by thermoelectric power, temperature dependence of resistivity, Raman measurement of a certain phonon mode frequency, or by appropriately annealing at a high temperature in a predetermined oxygen-containing atmosphere. Once determined, the critical doping state can be obtained, or can be determined from the ratio: Tc / Tc, max. Here, Tc, max is the superconducting phase curve Tc (
This is the largest Tc observed in p) and is expected to occur at approximately p = 0.16. The doping state or hole concentration of the HTSC can be adjusted by cation substitution or by increasing the oxygen content of the material beyond the oxygen content that provides the maximum Tc, or by a combination thereof.

[0010] Cation substitution to achieve critical doping is based on altervale
nt) substitutions, e.g. Ca2 ⁺ , Li ⁺ , Na ⁺ or K ⁺ of R3 ⁺ in 123, 247 and 124 materials
, Replacement of Ba ²⁺ with Li ⁺ , Na ⁺ or K ⁺ in 123, 247 and 124 materials, replacement of Ca ²⁺ with R ³⁺ in Bi-2212, Tl-1212, Tl-2212 and Hg-1212 , B
Replacement of Bi ³⁺ with Pb ²⁺ in i-2212 and Bi-2223, and Tl-1212 and Tl-2
This can be done by replacing Tl ³⁺ at 212 with Pb ⁴⁺ . For example, the compound _{Tl 0 .5 Pb 0.5 Sr 2 CaCu} 2 O 7 has a fixed stoichiometric oxygen content, therefore by changing the oxygen content is adjusted to a critical doping It is not possible. During preparation, this compound is overdoped with Tc = 79K, the expected hole concentration is p = 0.215, and the substitution at Ca sites by 0.2-0.25Y or Sr
With the substitution of 0.2-0.25La at the site, the doping state is optimized doping
It can be reduced to p = 0.16, where Tc is maximized to 105-107K. According to the invention, preferably the compound is substituted with 0.12 ± 0.04Y for Ca, or
Substitute Sr with ± 0.04La to achieve critical doping. Other rare earth elements can be utilized in this and other HTSC compounds in a similar manner. However, small rare earth elements should preferably be replaced with Ca, and large rare earth elements
Preferably it should be replaced with Sr. Of course, it is also possible to use a combination of substitution at the Sr and Ca sites. Quite generally, L in any HTSC material
The i ⁺ substitution is suitable for increasing the hole concentration of the material.

[0011] Oxygenation to achieve critical doping can be achieved by known annealing in an oxygen-containing atmosphere or by titration using electrochemical means. To achieve this oxygen content required for critical doping in any HTSC, 1
It may require the use of oxygen pressures above atmospheric pressure or the use of annealing temperatures lower than those conventionally used to produce the HTSC. Depending on the density of the HTSC, such annealing can take many days to equilibrate and use higher oxygen pressures at higher temperatures, where oxygen uptake rates are high It may be even more advantageous, or it may be more advantageous to use a combination of careful substitution and oxygenation that does not require such complete oxygenation. Alternative replacement of the cation tends to alter the oxygen content. Thus, substitution by Ca ^{2 +} in the R ³⁺ is the same annealing conditions, resulting in a greater oxygen deficiency (large [delta]) relative to the compound unsubstituted. This large oxygen deficiency can be eliminated by low-temperature oxygen annealing. Therefore, complete oxygenation of YBa ₂ Cu ₃ O _{7- δ} is 380 ° C. in oxygen.
Can be achieved by annealing at Y _1-x Ca _x Ba ₂ Cu ₃ O _{7- δ} (for example, x = 0.2
) Requires a low temperature, for example 300-350 ° C. Such low temperatures require longer annealing times. Similar considerations apply to R-247.

The HTSC material is a material containing Bi-Sr-Ca-Cu-O as a main component, for example, a nominal composition: Bi_Two Sr_TwoCaCu_TwoO_{8+ δ}Bi-2212 (where 0 ≦ δ ≦ 0.35) or nominal composition: Bi_TwoSr _Two Ca_TwoCu_ThreeO_{10+ δ}Bi-2223 (where 0 ≦ δ ≦ 0.35) (where Bi is Pb, Hg
, Re, Os, Ru, Tl, V, Cr, Zr, Nb, Mo, Hf, Ta, W, Co or Sm
Or Sr can be partially replaced by Ba or a large lanthanoid rare earth element
, Or Ca can be partially replaced by Y or, for example, a lanthanoid rare earth element,
In the chemical formula, it is known in the art that for such oxide materials, stoichiometric
Small changes are perceived to be normal). Bi-2212 and Bi-2223
Where Bi is usually partially substituted with Pb, so Bi is Bi_1-zPb_zCan be (
Here, 0 ≦ z ≦ 0.3). Particularly preferred compounds are Bi_{2 + e}Sr_TwoCaCu_TwoO_{8+ δ}, Bi_{2 + x + e} Sr_2-xyCa_{1 + y}Cu_TwoO_{8+ δ}, Bi_{2 + e}Sr_TwoCa_TwoCu_ThreeO_{10+ δ}And Bi_{2 + x + e}Sr_2-xCa_TwoCu_ThreeO_10+
δ(Where 0 <(e and x and ± y) ≦ 0.4) and Bi_1.9Pb_0.2Sr_1.9Ca₁Cu_TwoO_{8+ δ}To
Including. Bi-2212 and Bi-2223 doping state, for example, Ca in Bi-2212
Or the Bi of Bi-2212 and Bi-2223 is replaced with R (where R is Y or any other
Lanthanoid rare earth element) or by changing δ
Cation substitution, which increases the hole concentration p.

[0013] Bi_1.9Pb_0.2Sr_1.9Ca₁Cu_TwoO_{8+ δ}For example, in an oxygen partial pressure of 0.1 bar, about (570
± 15) ° C or a combination of temperature and oxygen partial pressure giving the same δ value.
Then, δ can be fixed by annealing the HTSC. only
A slight variability in δ is possible with Bi-2223, which reduces the hole concentration by almost
Change slightly. Bi-2212 can be completely oxygenated up to p ≒ 0.22 or 0.225.
And Bi-2223 has p ≒ 0.17 or at most 0.1
It is only doped up to 8. Alternatively, the Bi-2223 material may contain Bi-2223 in Bi-2223.
-2212 can be prepared to grow together. The mutual growth of Bi-2212 in Bi-2223 is
Enhance the former doping state. Such hole-doping cross-growth is
Very little (<1%, preferably <0.1%) Y or lanthanoid rare earth element at the site
Can be introduced by substituting In a preferred form, Bi_1.8Pb_0.3Sr_1.9Ca_TwoC
u_ThreeO_{10+ δ}The Bi_1.8Pb_0.3Sr_1.9CaCu_TwoO_{8+ δ}Can incorporate the mutual growth of the Bi _1.75 Pb_0.35Sr_1.9Ca_TwoCu_ThreeO_{10+ δ}The Bi_1.75Pb_0.35Sr_1.9CaCu_TwoO_{8+ δ}Mutual growth
Can be incorporated, Bi_1.73Pb_0.34Sr_1.9Ca_1.99Cu_3.04O_{10+ δ}The Bi_1.73Pb_0.34 Sr_1.9CaCu_TwoO_{8+ δ}Can incorporate the mutual growth of the Bi_1.88Pb_0.23Sr_1.96Ca_1.95Cu _2.98 O_{10+ δ}The Bi_1.88Pb_0.23Sr_1.96CaCu_TwoO_{8+ δ}Can incorporate the mutual growth of
Come again, Bi_1.84Pb_0.28Sr_1.93Ca_1.98Cu_2.96O_{10+ δ}The Bi_1.84Pb_0.28Sr_1.93CaCu_Two O_{8+ δ}Can incorporate mutual growth.

The HTSC may be an HTSC based on R-Ba-Ca-CuO, such as the material R-123, which has a nominal composition: Rba ₂ Cu ₃ O _{7- δ.} Yes (where R is Y or a lanthanoid rare earth element or a combination thereof, and 0 ≦ δ ≦ 0.5 (and R
May be partially substituted by Ca, Ba may be partially substituted by Sr, La or Nd, etc., and furthermore, in the art, slight variations in stoichiometric It is recognized as being common in various oxide materials). The critical doping is preferably optional cation substitution, e.g. of R, Ca, Li, Na
Or K, or in combination with replacement of Ba by Li, Na or K, δ ≦ 0.
Achieved by oxygenation up to 05. The critical doping is the point δ = 0 for R = Y
, And for small rare earth elements, such as Tl or Lu, close to zero but to δ of> 0. Preferably, when R is a large rare earth element, a small amount of Ca can be replaced with R to achieve critical doping. For large rare earth elements, the critical doping state cannot be achieved simply by reducing δ to near zero.

This is due in part to the fact that some R is left on the Ba site, where R is a large rare earth element, and appropriate treatment to avoid such substitutions. However, the charge transfer from the CuO chain to the CuO ₂ plane is insufficient to achieve critical doping. Preferred compounds are R _1-x Ca _x Ba ₂ Cu ₃ O _{7- δ} (where 0 ≦ x ≦ 0.35 and
0 ≦ δ ≦ 0.5) and R _1-x Li _x Ba ₂ Cu ₃ O _{7- δ} (where 0 ≦ x ≦ 0.35 and 0 ≦ δ ≦ 0.5)
And where x and δ are adjusted together such that the copper-oxygen surface is critically doped as described above. Preferably, δ is made as small as possible in proportion to the critical doping. Thus, in a preferred form, a value for x is chosen, typically such that x ≦ 0.1, to achieve critical doping such that δ ≦ 0.10. It is even more preferred that x ≦ 0.05 and δ ≦ 0.03.

The HTSC may be R-247, which has a nominal composition of R_2-xCa_xBa _Four Cu₇O_{15- δ}(Where R is Y or a lanthanide rare earth element or a combination thereof)
0 ≦ δ ≦ 0.5 (and R may be partially substituted by Ca;
Ba may be, for example, partially substituted by Sr, La or Nd;
Furthermore, small changes in stoichiometry are common in such oxygenate materials.
It is recognized that ). ). Critical doping, for example
For example, R may be replaced with Ca, Li, Na or K, or Ba may be replaced with Li, Na or K.
Oxygenation to δ ≤ 0.5, optionally in combination with
U. A preferred compound is R_2-xCa_xBa_FourCu₇O_{15- δ}(0 ≦ x ≦ 0.35 and
0 ≦ δ ≦ 0.5) and R_2-xLi_xBa_FourCu₇O_{15- δ}(0 ≦ x ≦ 0.35 and 0
≦ δ ≦ 0.5), where x and δ are such that the copper-oxygen surface is critical as described above.
Together to be doped. Preferably, δ is the critical dopin
And as small as possible to correspond. Thus, in a preferred form, x
Is typically such that this critical doping is achieved with δ ≦ 0.10.
Is selected such that x ≦ 0.1. More preferably, x ≦ 0.05 and δ ≦ 0.
03. 247 typically has less doping compared to the equivalent 123 material.
The magnitude of the Ca content, indicated by x, is greater than in the equivalent 123 material.
It will need to be big. Small rare earths such as Tl and Lu are large rare earths
This is desirable because higher Ca contents can be achieved than for the elements.

The HTSC may be R-124, which has a nominal composition of RBa_TwoCu_Four O₈(Where R is Y or a lanthanide rare earth element, and 0 ≦ δ ≦ 0.35 (and
And R may be partially substituted by Ca, Ba is, for example, partially
May be substituted by Sr, La or Nd, and furthermore, in stoichiometric amount
It is recognized that small changes are common in such oxygenate materials
. ). ). Critical doping is, for example, where R is Ca, Li, N
a or K, or cation substitution to replace Ba with Li, Na or K.
Achieved. A preferred compound is R_1-xCa_xBa_TwoCu_FourO₈And and R_1-xLi _x Ba_TwoCu_FourO₈(0 ≦ x ≦ 0.35). 124 is the equivalent of 247 and 12
Typically, the doping amount is lower than that of the three materials, so that a high cation substitution level is obtained.
Bells are needed more than in equivalent 247 and 123 materials. Tl and Lu
Such small rare earths are desirable because they can achieve the required high Ca content.

HTSC has a nominal composition of TlSr_TwoCuO_{5+ δ}Tl1201, which is also
Is the nominal composition, TlSr_TwoCaCu_TwoO_{7+ δ}Tl-1212 or designation
As a composition, TlSr_TwoCa_TwoCu_ThreeO_{8+ δ}Tl, such as Tl-1223
-Sr-Ca-Cu-O based material (and Tl may be
Sr may be partly substituted by La or Ba.
Ca may be partially substituted, for example,
In addition, small changes in stoichiometry in these formulas may be
It will be appreciated that such oxygenate materials are common. ). preferable
The compound is Tl_0.5Pb_0.5Sr_2-wBa_wCaCu_TwoO₇, Tl_0.5Pb_0.5Sr_2-x
La_xCaCu_TwoO₇, And Tl_0.5Pb_0.5Sr_TwoCa_1-yR_yCu_TwoO₇(However, 0 ≦
(X and w) ≦ 2, 0 ≦ y ≦ 1, and R is Y or a lanthanide rare earth element
Or more generally, (Tl, Pb, Bi)₁(Sr, Ba
, La)_Two(Ca, R)₁Cu_TwoO₇And Tl_0.5Pb_0.5Sr_2-xCa_xCa_TwoCu_ThreeO ₉ And Tl_0.5Pb_0.5Sr_2-wxBa_wCa_xCa_TwoCu_ThreeO₉(0 ≦ x, w ≦ 1),
Or more generally (Tl, Pb, Bi)₁(Sr, Ba, La)_TwoCa_TwoCu_Three O₉(−0.3 ≦ δ ≦ 0.3).

HTSC is based on mercury, such as composition Hg-1212, referred to as HgBa ₂ CaCu ₂ O _{6+ δ} , or composition Hg-1223, referred to as HgBa ₂ Ca ₂ Cu ₃ O _{8+ δ} . HTSC, wherein Hg may be partially substituted with Tl, Bi, Pb or Cd, and Ba may be partially
It is recognized in the art that slight stoichiometric variations in such oxygenates are common in these formulas, for example, they may be substituted with Sr. ) Critical adjusted doped state _{0.91T c, max = T c =} 0.96T c, max, more _{preferably, 0.92T c, max = Tc =} 0.95T c, max, and, = most preferably T _c ( 0.93 ± 0.005)
It can be defined quantitatively by HTSC with an overdoping Tc that satisfies Tc _{, max} . The critically adjusted doping state is in μV / K, -4 <Q (T _RT ) <-1, more preferably -3 <Q (T _RT ) <-2, (280K <T _RT <300K) HTSC with an overdoping Tc of room temperature thermal power Q (T _RT ) that satisfies

[0020] Doping while being critical adjustment, from 250K, to 20K below large temperature than T _c, be quantitatively defined by HTSC with excess doping T _c which is the normal state constant volume resistivity is maintained constant it can. In a more preferred embodiment, the normal state constant volume resistivity maintains its linearity from 500K to a temperature less than 20K above _Tc . The critically adjusted doping state is the temperature of the standard state constant volume resistivity when the temperature decreases from 250K to a temperature greater than _Tc below 20K, more preferably from 500K to a temperature greater than _Tc below 20K. it can be quantitatively defined by HTSC with excess doping T _c that derivative is maintained within 5% ±.

The critically tuned doping state may be defined by annealing in a predetermined oxygen-containing atmosphere to produce a critically overdoped Tc;
The Tc is or T _c thermal power or normal state resistivity has a preferred range of the heat capacity, NMR spectrophotometry, with T _c with an emulated gap strictly suppressed to 0 as determined by the magnetic susceptibility or other means is there. For example, Bi _1.9 Pb _0.2 Sr _1.9 CaCu ₂ O _{8+ δ} may be annealed at 570 ° C. in a mixture of 10% oxygen and 90% nitrogen gas (oxygen partial pressure 0.1 bar), T _{c, max} = 90.5 A critical overdoping of T _c = 83.7 K is achieved in the K system. As a result, a 7.5% reduction in Tc, a hole concentration p = 0.19, and a maximum energy density of 1.76 J / g.at can be obtained as measured by heat capacity. Y _0.8 Ca _0.2 Ba ₂ Cu ₃ O _{7- δ} is 530 ° C in oxygen
T _{c, max} = 85.5K, T _c = 79K, ie 7.5% decrease in Tc, estimated hole concentration p = 0.19, maximum energy density measured by heat capacity 2.5 J / g.at
Is achieved. Other combinations of temperature and oxygen partial pressure to achieve critical doping (eg, higher temperatures and consequently higher oxygen partial pressures) can also be used.

The doping state in any HTSC can be determined by Raman measurements of the frequency of the particular phonon mode, the desired frequency being determined first by the hole concentration, thermal power, resistivity, oxygen annealing or T _c value. Is confirmed from the correlation with one of the above. One such mode is 630 cm ^-2 A _lg mode. Achieving alignment of oxygen to the chain with minimum gaps on the chain to ensure sufficient charge transfer to the CuO ₂ plane at R-123 and when achieving the desired degree of oxygenation is necessary. The slow cooling from the annealing temperature to room temperature allows the oxygen to be aligned on the chain since the misalignment of oxygen occurs at T ≧ 50 ° C. so that the charge transfer and maximum doping are complete. Ideally needed. Furthermore, the chain without such defects, further contributing to the superfluid density, therefore, further J _c is increased.

In order to achieve optimal doping at the grain boundaries, the bulk material is overdoped and the grain boundaries between the grains in the HTSC are doped, maximizing the critical current density especially in the grain boundaries of the HTSC. Thus, the current between the crystal grains can be maximized even if the maximization of the critical current density in the crystal grains is sacrificed to some extent.
In contrast to bulk, cation solubility and oxygen activity will be different at grain boundaries.
For example, if Ca ²⁺ substitution is preferred at the grain boundaries for the bulk, it is somewhat anticipated that both grain boundaries and bulk will be simultaneously critically doped. If Ca ²⁺ substitution is preferred in the bulk with respect to grain boundaries, compromise may be required, as described above. Due to site disorder at the grain boundaries, the energy wall for oxygen occupancy will not be as deep as in the bulk. As a result, lower temperatures (and / or high oxygen pressures) required to oxygenate the bulk may be required to oxygenate grain boundaries. Annealing temperatures as low as 100 ° C. to 200 ° C. may be required to properly oxygenate grain boundaries to achieve critical doping therein. Oxygen diffusion at such low temperatures will be prohibitively delayed in the bulk, but the grain boundary diffusion rate will be significantly increased due to the misalignment therein, and thus the critical oxygenation of the grain boundaries Will be fully feasible below 300 ° C or even below 300 ° C.

The method of the present invention can be used in forming HTS materials into flexible wires or tapes by techniques known in the art as powder-in-tube processing. This technique is used especially for Bi-2212 or Bi-2223 materials. Powders of these materials or precursors of these materials are packed into metal tubes, often made of silver metal or silver alloy, and then, by a process of deformation and heat treatment, stretch the tubes into long wires, The oxygenates react to give a highly textured Bi-222
3. For example, an HTSC core is formed. The wire can be bundled once or multiple times to form a multifilament wire. Metal alloy precursors can be used to form such long wires, and heat treatment and deformation convert and react the metal alloy to oxygenates to form a fully textured Bi.
-2223, for example, an HTSC core can be formed. Also, other techniques, such as coating or metalworking, can be used to form long wires or tapes. The material may also be formed as a thin film using any method as is known in the art, or bulk melt-processed single-domain or neighboring-
It can be formed as a single-domain monolith.

[0025]

The present invention is further described by the following examples. Example 1 A sample of Y _0.8 Ca _0.2 Ba ₂ Cu ₃ O _{7- δ} was studied using heat capacity C _p and NMR spectroscopy as a function of oxygen deficiency δ. This HTS material is particularly useful. This is because when δ changes from 1 to 0, the doping state changes from a heavily underdoped state to a heavily overdoped state. Hole concentration was determined using the thermoelectric power correlation between Q (290) and p (Tallon et al., US Pat. No. 5,619,141). This value is the parabolic correlation between _Tc and p, _Tc (p) = _{Tc, max.} [1-82.6 (p-0.16
² ) and found to be in good agreement with the value determined from the estimate of p using the sum of the valencies from the neutron diffraction refinement in atomic coordinates. T _{c, max} is approximately the parabolic hole concentration dependence of T _c (p) (para
bolic hole concentration dependence). The pseudogap energy E _g was determined by fitting the temperature dependence of entropy, and its value was confirmed by fitting to a temperature dependent ⁸⁹ Y NMR Knight shift. Both T _c and E _g are plotted in FIG. 1 as a function of p. E _g decreased progressively with increasing doping and became zero at p = 0.19, ie, about 0.03 holes / copper above the optimum concentration where the overdoped side and T _c were maximized. . Alternatively, when the reduced T _c is in excess doping T _c, 7.4% lower than the _max, E _g became zero. The condensing energy U _o is obtained by _calculating the entropy S (T) between the standard state curve S _NS (T) and the superconducting curve S _SC (T) by T = 0.
From T to _Tc . U _o was found to maximize very sharply at p = 0.19 when E _g reached 0. The product U _o xi] _ab does not become a very sharp peak, data plotted in Figure 1,
This indicates that the peak has been maximized again when E _g → 0 after passing through a slightly sharp peak. As a result, flux pinning and critical current will sharply maximize at this point. Most attention deserves, U _o ξ _ab value at the optimum doping for the maximum T _c is about 39J. nm / mol, and almost twice this value is E _g →
0 (76 J. nm / mol) in critical doping. Such a large increase for a small decrease in _Tc (6K) is quite unexpected and is not known until now and offers the important benefit of maximizing the critical current with a slight decrease in the _Tc value. . For the other HTSC materials, the _Tc reduction was proportionally the same, with Bi-
For 2233, the T _{c, max on} the overdoping side from 110K to 10
The drop to 3 or 102K is not a significant drop in _Tc , but allows doubling of flux pinning when cooled to liquid nitrogen temperature.

Example 2 Overdoped Bi with Different δ_TwoSr_TwoCaCu_TwoO_{8+ δ}And different
Underdoped Bi with δ_TwoSr_TwoCa_0.7Y_0.3Cu_TwoO_{8+ δ}Sample
Was replaced at the Cu site in the range of Co. T_cImpurity depr
ession) speed dT_c/ Dy from the Co fraction y
T = T_c= C at_pWill determine the value of / T. Scaling relation (scalin
g relation) using (Tallon, Phys. Rev. B-58, R5956 (1998)), E_gas well as
U_oWill decide. These values are plotted with solid symbols in FIG.
did. Unfilled triangles indicate Y by NMR measurement._0.8Ca_0.2Ba_TwoCu_ThreeO _{7- δ} E decided on_gValue. These are two methods E_gComparable for
It shows that a good result was given. Furthermore, Bi_TwoSr_TwoCaCu_TwoO_{8+ δ}About
And Y_0.8Ca_0.2Ba_TwoCu_ThreeO_{7- δ}As in_oIs E_gWhen it becomes 0
And in the over-doped region, unexpectedly passed a sharp maximum. Further
, U_oIs almost doubled in the progression from optimal doping to critical doping.
Was. Data for Bi-2212 was confirmed by direct heat capacity measurements.
. E_gAt critical doping where_oAnd U_oThe maximization of ξ is La_2-xSr _x CuO_FourAnd Tl_0.5Pb_0.5Sr_TwoCa_1-xY_xCu_TwoO₇As confirmed in
In addition, it is considered to be a universal behavior among HTSC materials. Therefore,
Behavior is common to thallium-based and mercury-based HTSCs
Is reasonable.

Example 3 A sample of Y _0.8 Ca _0.2 Ba ₂ Cu ₃ O _{7- δ} was studied using muon spin relaxation as a function of oxygen deficiency δ. The muon spin relaxation rate σ _{0 at} T = 0 is proportional to λ _L ^-2 . FIG. 3 shows a plot of λ _L ^-2 as a function of hole concentration p. It was observed that λ _L ^-2 passed through a sharp maximum at the critical point where E _g was 0 and p was approximately 0.19. λ _L ^-2 is a key parameter in determining the size of the irreversible region. As a result, p is approximately 0.
Critical doping at point 19 will not only sharply maximize flux pinning, but will also result in high irreversible regions.

Example 4 Y_0.8Ca_0.2Ba_TwoCu_ThreeO_{7- δ}7 pellets at different temperatures and acid
Tempering under elementary partial pressure and then abrupt in liquid nitrogen at equilibrium oxygen content
Cooled down. Thus, seven samples having different values of oxygen deficiency δ, that is, 0.09
Samples with seven different hole concentrations in the range ≦ p ≦ 0.23 were obtained.
These pellets are made using isopropyl alcohol as a lubricant and
And crushed with a pestle for 1 hour to obtain a very fine powder. Isopropyl powder
Suspend in coal, leave for 30 minutes, discard fluid with remaining suspension and evaporate
And dried. In this way, large particles settle and the size of the remaining particles is ≦
It was 5 μm. These small particles were thoroughly mixed with the epoxy. Then mixing
The object is placed in a rubber mold, and in an electromagnetic field, the particles are aligned along the c-axis parallel to the field.
The epoxy hardened during that time. The space for alignment is about 1 Tesla.
Was. Alignment after curing was confirmed by x-ray diffraction, which was in a plane perpendicular to the alignment field.
Showed the primary c-axis reflection at. Cut out a small sample from each of the seven aligned samples
And the strength of the magnetic field using a vibrating-sample magnetometer
And the magnetization of the sample as a function of temperature. Figure 4 shows the function of p in units of emu
The magnetization is plotted as 0.2T, 0.5T, and 20T.
It is measured at temperatures of K, 40K and 60K. From the data, the criticality of p = 0.19
It can be seen that a sharp maximum is formed in the doping concentration. as a function of p
The parabola of all Tc is also plotted for reference and is highly overdoped.
Indicates that a sharp maximum value occurs. This parabola has the formula Tc = Tc
, Max [1-82.6 (p−0.16)^TwoIs calculated using this formula.
Is the Tc (p) of many HTS cuprates, probably all HTS cuprates
Is described. The criticality of doping is extremely high in this plot, especially at low temperatures.
And obvious. Irreversible line H at T = 0.75 Tc for each sample^*(T
) Was also measured, which is plotted in FIG. Where H^*Has a sharp maximum
It can be seen that the maximum occurred beyond the critical doping,
Is H^*Is the product λab^-2. λc^-2Because they are controlled by
, Where λab^-2Is the penetration depth in the plane, λc^-2Is the c-axis penetration depth. λab ^-2 Is U₀Is proportional to the superfluid density, which is proportional to
Form a high value. On the other hand, λc is a monotonically decreasing c-axis resistivity with respect to doping p.
It is proportional to ρc. Thus, the maximum in the irreversible region is exactly as shown in FIG.
Occurs beyond the critical doping. However, in FIG. 5, T = 0.7
Note that this data is not for a fixed temperature because it is 5Tc
Should. Critical doping for fixed temperature (and fixed field) conditions
At which the critical current is maximized. In the sample of this example, all the crystal grains
It should also be noted that they are separated from each other. All currents are currents in the grains
Yes, and does not reflect the grain boundary current.

Example 5 The sample of Example 4 was examined with a scanning electron microscope to measure the dispersion of the particle size. The total mass of each sample was then measured after pyrolysis of the epoxy. The magnetization data of Example 4 was then converted to a critical current density Jc using the well-known Bean formula. 0.
The values of Jc thus obtained at a magnetic field of 2 Tesla and at temperatures of 10 K and 20 K are plotted in FIG. 6 as a function of the hole concentration p. The reversibility temperature Tirr at 5 Tesla is also plotted in this figure along with the p-dependence of the transition temperature Tc. It can be seen that both Jc and Tirr maximize near the critical doping of p = 0.19, clearly exceeding the point of p = 0.16 where Tc maximizes.

[0030] Example _{6: Tl 0.5 Pb 0.5 Sr 2} Ca 1-x Y x Cu 2 O 7 and _{Tl 0.5 Pb 0.5 Sr 2-y} La y C
aCu ₂ O ₇ (where x = 0, 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) in oxygen at 1060 ° C. with Tl, Pb, Y, La and Cu.
Was synthesized by a solid-phase reaction of pellets of a stoichiometric mixture of oxygenates of the above and carbonates of Ca and Sr. Tl ₂ O ₃ is first reacting the precursor in the absence, Tl ₂
O ₃ was added for further reaction at 1060 ° C. The reacted material was ground and re-sintered under the same conditions. Using the Tl ₂ O Tl ₂ O ₃ for a volatile small excess (5%) of _3, and sealed during the gold tube under oxygen by bending the ends of the tube. The samples were then evaluated by measuring the specific resistance, ac susceptibility, and heat capacity. When x or y = 0, the material is overdoped and increasing x or y decreases the hole concentration. It has been found that the Tc value is approximately parabolic dependent on the amount of substituted Y or rare earth element, forming a maximum T _{c, max} = 107 K when x is 0.25. However, the heat capacity jump formed a sharp maximum at x = 0.15. This corresponds to the critical doping point. The jump in heat capacity at the superconducting transition is directly related to the cohesive energy and hence the pinning of the magnetic flux. _{Tl 0.5 Pb 0.5 Sr 2-y} La y CaCu 2 Similar results O ₇ was obtained. Thus, it has been found that the critical current-related properties of these materials increase to a maximum in the slightly overdoped region, although at critical doping but not at the optimum doping where Tc forms a maximum.

[Brief description of the drawings]

FIG. 1. Tc, pseudo gap energy Eg and product for Y _0.8 Ca _0.2 Ba ₂ Cu ₃ O _{7- δ}
Plots the hole concentration dependence of the U ₀ xi] _ab, where xi] _ab is the coherence length of the ab- surface.

FIG. 2 is a plot of the hole concentration dependence of Tc, Eg, and U ₀ with respect to Bi ₂ Sr ₂ CaCu ₂ O _{8+ δ} .

FIG. 3 is a plot of the hole concentration dependence of λ _L ^-2 with respect to Y _0.8 Ca _0.2 Ba ₂ Cu ₃ O _{7- δ} .

Fig. 4 p- of magnetization (proportional to critical current) of YBa ₂ Cu ₃ O _{7- δ} particles arranged in epoxy
It is a plot of dependency. As shown, data is shown for various field strengths and temperatures. This parabola is Tc plotted as a function of p.

FIG. 5 is a plot of the p-dependence of the irreversible magnetic field at T = 0.75 Tc for Y _0.8 Ca _0.2 Ba ₂ Cu ₃ O _{7- δ} particles arranged in epoxy. This parabola has a hole concentration p
Here is Tc plotted as a function of.

FIG. 6: p-dependence of magnetization-critical current density at 0.2 Tesla at 10K and 20K and 5 Tesla for Y _0.8 Ca _0.2 Ba ₂ Cu ₃ O _{7- δ} particles arranged in epoxy. 3 is a plot of the p-dependence of the irreversible temperature at. This parabola is Tc plotted as a function of hole concentration p.

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Claims (72)

[Claims] 1. A method for manufacturing a high-temperature superconducting cuprate material (HTSC) for maximizing a critical current density (Jc) of the high-temperature superconducting cuprate material, the doping state of the material or its hole. Controlling the concentration to be greater than the doping state of the material or its hole concentration to provide a maximum superconducting transition temperature (Tc), thereby increasing the critical current density of the material. Production method of plate material. 2. The method of claim 1 including controlling the doping state or its hole concentration such that the normal state pseudogap is near a value that decreases to a minimum value. 3. The method according to claim 1, further comprising the step of adjusting the hole concentration p so as to fall within a range of 0.18 ≦ p ≦ 0.20. 4. The method according to claim 3, comprising adjusting the hole concentration p to be about 0.19. 5. The method of claim 3, comprising adjusting the hole concentration p to p = 0.19 ± 0.005. 6. The method according to claim 1, further comprising the step of adjusting the hole concentration such that Tc relating to the HTSC is within a range of 0.91 Tc, max ≦ Tc ≦ 0.96 Tc, max, wherein Tc, max depends on the hole concentration. The method according to any one of claims 1 to 5, wherein the value is a maximum value of Tc that varies. 7. Tc is set to fall within a range of 0.92Tc, max ≦ Tc ≦ 0.95Tc, max,
7. The method of claim 6, comprising adjusting the hole concentration. 8. The method according to claim 6, further comprising the step of adjusting the hole concentration such that Tc = (0.93 ± 0.005) Tc, max. 9. A method for controlling the hole concentration p such that the room temperature thermoelectric power Q (T _RT ) of the HTSC is within a range of −4 <Q (T _RT ) <− 1, The method according to any one of claims 1 to 8, wherein the unit of Q (T _RT ) is μV / K, and the room temperature T _RT is in the range of 280K <T _RT <300K. 10. The method according to claim 9, further comprising a step of adjusting the hole concentration p such that the thermoelectric power Q (T _RT ) is within a range of −3 <Q (T _RT ) <− 2. Method. 11. The temperature derivative of the standard state resistivity of the HTSC is 250 K
The method according to any one of claims 1 to 10, further comprising the step of adjusting the hole concentration so that when the temperature is reduced to a temperature lower than Tc by less than 20K, the hole concentration is kept constant within a range of ± 5%.
The method described in the section. 12. The temperature differential coefficient of the standard state constant volume resistivity is kept constant within ± 5% when the temperature is reduced from 500 K to a temperature less than 20 K larger than Tc. The method according to any one of claims 1 to 11, further comprising adjusting the hole concentration. 13. The method of claim 1, further comprising the step of doping a grain boundary region between individual grains in the HTSC to overdope so as to maximize a critical current density.
13. The method according to any one of 12 above. 14. The method according to claim 1, wherein the HTSC is an HTSC containing Bi-Sr-Ca-Cu-O as a main component. 15. Ca is partially converted to Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
15. The method of claim 14, comprising adjusting the hole concentration by m, Yb or Lu or any combination thereof, or by partially replacing Bi with Pb. 16. The method according to claim 14, comprising adjusting the hole concentration by adjusting the oxygen content of the HTSC. 17. The HTSC is represented by the composition (Bi _1-z Pb _z ) _{2 + x + e} Sr _2-xy Ca _{1 + y} Cu ₂ O _{8+ δ} , where 0 ≦ (e And x and ± y) ≦ 0.4, 0 ≦ z ≦ 0.3 and 0 ≦
15. The method of claim 14, wherein δ ≤ 0.35. 18. The HTSC of the composition Bi _1.9 Pb _0.2 Sr _1.9 Ca ₁ Cu ₂ O _{8+ δ} and a temperature of about (570 ± 15) ° C. in an oxygen partial pressure of about 0.1 bar. At a temperature or a combination of temperature and oxygen pressure or oxygen partial pressure that gives an equivalent value of δ.
18. The method according to claim 17, comprising the step of fixing δ by annealing HTSC. 19. The HTSC is represented by the composition (Bi _1-z Pb _z ) _{2 + x + e} Sr _2-x Ca ₂ Cu ₃ O _{10+ δ} , where 0 ≦ (e and x 15. The method of claim 14, wherein :) ≤ 0.4, 0 ≤ z ≤ 0.3, and 0 ≤ δ ≤ 0.35. 20. A method for preparing a material for incorporating a _co- growth portion of (Bi _1-z Pb _z ) _{2 + x + e} Sr _2-xy Ca _{1 + y} Cu ₂ O _{8+ δ} , wherein 0 ≦ (e and x) ≦ 0.4, 0 ≦ z ≦ 0
20. The method according to claim 19, wherein 0.3 and 0?? 0.35. 21. The method according to claim 21, further comprising the step of causing the mutual growth by partially replacing Ca in the HTSC with R, wherein R is Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm
21. The method of claim 20, which is Yb, Lu, or any combination thereof. 22. The HTSC is an HTSC containing R-Ba-Cu-O as a main component, wherein R is
14. The method according to any one of claims 1 to 13, wherein the method is Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu or any combination thereof. 23. The hole concentration is reduced by partially substituting R for Ca, Li, Na or K or a combination thereof, or partially substituting Ba for Li, Na, K or a combination thereof. 23. The method of claim 22, comprising the step of adjusting. 24. The method of claim 22 or 23, comprising adjusting the hole concentration by adjusting the oxygen content of the HTSC. 25. The HTSC according to claim 22, wherein the HTSC is represented by the composition R _1-x Ca _x Ba ₂ Cu ₃ O _{7- δ} , wherein 0 ≦ x ≦ 0.35 and 0 ≦ δ ≦ 0.5. The described method. 26. The HTSC according to claim 1, wherein the HTSC has the composition Y _0.8 Ca _0.2 Ba ₂ Cu ₃ O _{7- δ} and is in oxygen at a temperature of about (530 ± 15) ° C. or equivalent δSC. 24. The method of claim 23, comprising the step of fixing δ by annealing the HTSC at a combination of temperature and oxygen pressure or oxygen partial pressure that gives a value of δ. 27. The HTSC is of the composition R _1-x Li _x Ba ₂ Cu ₃ O _{7- δ} where 0 ≦ x ≦ 0.35 and 0 ≦ δ ≦ 0.5. The described method. 28. The HTSC is of the composition R _2-x Ca _x Ba ₄ Cu ₇ O _{15- δ} , wherein 0 ≦ x ≦ 0.35 and 0 ≦ δ ≦ 0.5. The described method. 29. The method of claim 22, wherein said HTSC is of the composition R _1-x Ca _x Ba ₂ Cu ₄ O ₈ , wherein 0.10 ≦ x ≦ 0.35. 30. The method according to claim 1, wherein the HTSC is an HTSC containing Tl-Sr-Ca-CuO as a main component. 31. Ca or Sr is converted to Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
31. The method of claim 30, comprising adjusting the hole concentration by m, Yb or Lu or any combination thereof, or by partially replacing Tl with Pb. 32. The method of claim 30 or 31, comprising adjusting the hole concentration by adjusting the oxygen content of the HTSC. 33. The method according to claim 1, wherein the HTSC is an HTSC containing Hg as a main component. 34. Ca, Sr or Ba is partially converted to Y, La, Nd, Sm, Eu, Gd, Tb, D
The method of claim 33, comprising adjusting the hole concentration by substituting y, Ho, Er, Tm, Yb or Lu or any combination thereof, or partially substituting Hg with Pb. . 35. The method of claim 32 or 33, comprising adjusting the hole concentration by adjusting the oxygen content of the HTSC. 36. A high-temperature superconducting cuprate material prepared by the method according to any one of claims 1 to 35. 37. The doping state or hole concentration of a material to obtain a maximum superconducting transition temperature (Tc), and the standard state pseudo gap for the material is reduced to a minimum value, and the critical current of the material is reduced. High temperature superconducting cuprate material (HTSC) characterized by having a doping state or hole concentration near the value that maximizes the density (Jc). 38. The HTSC of claim 37, wherein said hole concentration p of said material is in the range of 0.18 ≦ p ≦ 0.20. 39. The HTSC of claim 38, wherein said hole concentration p is about 0.19. 40. The H according to claim 38, wherein the hole concentration p is p = 0.19 ± 0.005.
TSC. 41. The method according to claim 37, wherein Tc has a value within a range of 0.91Tc, max ≦ Tc ≦ 0.96Tc, max, where Tc, max is a maximum value of Tc that varies according to the hole concentration. HTSC according to any one of 40. 42. The HTSC according to claim 41, wherein Tc is within a range of 0.92Tc, max ≦ Tc ≦ 0.95Tc, max. 43. The HTSC of claim 41, wherein Tc = (0.93 ± 0.005) Tc, max. 44. The room temperature thermoelectric power Q (T _RT ) for the HTSC is in the range of −4 <Q (T _RT ) <− 1, wherein the unit of Q (T _RT ) is μV / K. , And room temperature T _RT is 280K <T _RT <3
The HTSC according to any one of claims 37 to 43, which is in the range of 00K. 45. The HTSC of claim 44, wherein said thermoelectric power Q (T _RT ) for said HTSC is in the range of −3 <Q (T _RT ) <− 2. 46. The temperature derivative of the standard state resistivity of the HTSC is 250 K
46. The HTSC of any one of claims 37 to 45, wherein the HTSC is maintained constant within ± 5% when reduced to a temperature less than 20K above Tc. 47. The temperature derivative of the standard state constant volume resistivity maintained constant within ± 5% when the temperature is reduced from 500K to a temperature less than 20K above Tc. HTSC according to any one of items 37 to 45. 48. The overdoping such that the doping state or hole concentration of the material in the grain boundary region between individual particles in the HTSC is near a value that maximizes the critical current density of the material. The HTSC according to any one of claims 37 to 47. 49. The HTSC according to claim 37, wherein the HTSC is an HTSC containing Bi-Sr-Ca-Cu-O as a main component. 50. The HTSC is represented by the composition (Bi _1-z Pb _z ) _{2 + x + e} Sr _2-xy Ca _{1 + y} Cu ₂ O _{8+ δ} , where 0 ≦ (e And x and ± y) ≦ 0.4, 0 ≦ z ≦ 0.3 and 0 ≦
50. The HTSC of claim 49, wherein δ ≤ 0.35. 51. The HTSC according to claim 50, wherein the HTSC is represented by the composition Bi _1.9 Pb _0.2 Sr _1.9 Ca ₁ Cu ₂ O _{8+ δ} . 52.The HTSC is represented by the composition (Bi _1-z Pb _z ) _{2 + x + e} Sr _2-x Ca ₂ Cu ₃ O _{10+ δ} , where 0 ≦ (e and x ) ≦ 0.4, 0 ≦ z ≦ 0.3, according to claim 49.
HTSC. 53. A _co- growth portion of (Bi _1-z Pb _z ) _{2 + x + e} Sr _2-xy Ca _{1 + y} Cu ₂ O _{8+ δ} is incorporated, where 0 ≦ (e and x and ± y) ≦ 0.4, 0 ≦ x ≦ 0.3 and 0 ≦ δ ≦ 0.35
53. The HTSC of claim 52, wherein 54. A composition represented by a composition Bi _1.8 Pb _0.3 Sr _1.9 Ca ₂ Cu ₃ O _{10+ δ} , and the mutual growth portion is represented by a composition Bi _1.8 Pb _0.3 Sr _1.9 CaCu ₂ O _{8+ δ} Is a thing,
54. The HTSC of claim 53. 55. A composition represented by a composition Bi _1.75 Pb _0.35 Sr _1.9 Ca ₂ Cu ₃ O _{10+ δ} , and the mutual growth portion is represented by a composition Bi _1.75 Pb _0.35 Sr _1.9 CaCu ₂ O _{8+ δ} 54. The HTSC of claim 53, wherein 56. A composition represented by a composition Bi _1.73 Pb _0.34 Sr _1.9 Ca _1.99 Cu _3.04 O _{10+ δ} , and the mutual growth portion is represented by a composition Bi _1.73 Pb _0.34 Sr _1.9 CaCu ₂ O _{8+ δ} 54. The HTSC of claim 53, wherein 57. A composition represented by a composition Bi _1.88 Pb _0.23 Sr _1.96 Ca _1.95 Cu _2.98 O _{10+ δ} , and the mutual growth portion is represented by a composition Bi _1.88 Pb _0.23 Sr _1.96 CaCu ₂ O _{8+ δ} 54. The HTSC of claim 53, wherein 58. A composition represented by a composition Bi _1.84 Pb _0.28 Sr _1.93 Ca _1.98 Cu _2.96 O _{10+ δ} , and the mutual growth portion is represented by a composition Bi _1.84 Pb _0.28 Sr _1.93 CaCu ₂ O _{8+ δ} 54. The HTSC of claim 53, wherein 59. The HTSC is an HTSC containing R-Ba-Cu-O as a main component, wherein R
49. The HTSC according to any one of claims 37 to 48, wherein is HT, Y, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu or any combination thereof. 60. A composition represented by the composition R _1-x Ca _x Ba ₂ Cu ₃ O _{7- δ} , wherein 0 ≦
60. The HTSC of claim 59, wherein x? 0.35 and 0??? 0.5. 61. A composition represented by a composition Y _0.8 Ca _0.2 Ba ₂ Cu ₃ O _{7- δ} , wherein 0
61. The HTSC of claim 60, wherein .16 ≦ δ ≦ 0.24. 62. The HTSC of claim 60, wherein δ = x ± 0.04. 63. A composition represented by a composition R _1-x Li _x Ba ₂ Cu ₃ O _{7- δ} , wherein 0 ≦
60. The HTSC of claim 59, wherein x? 0.3 and 0?? 0.5. 64. The HTSC of claim 63, wherein δ = (x / 2) ± 0.04. 65. A composition represented by the composition R _2-x Ca _x Ba ₄ Cu ₇ O _{15- δ} , wherein 0
60. The HTSC of claim 59, wherein? X? 0.35 and 0 ??? 0.5. 66. A composition represented by the composition R _1-x Ca _x Ba ₂ Cu ₄ O ₈ , wherein 0.1 ≦ x
60. The HTSC of claim 59, wherein ≤ 0.35. 67. The HTSC comprising Tl-Sr-Ca-Cu-O as a main component.
HTSC according to any one of the above. 68.A composition Tl _0.5 Pb _0.5 Sr ₂ Ca _1-x R _x Cu ₂ O ₇ and 0.06 ≦ x ≦
68. The HTSC of claim 67, wherein the HTSC is 0.18. 69. The HTSC of claim 68, wherein x = 0.12 ± 0.04. 70. A composition Tl _0.5 Pb _0.5 Sr _2-x R _x CaCu ₂ O ₇ where R is Y, La
67. The HTSC of claim 67, wherein Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb or Lu or any combination thereof, and wherein 0.06 x 0.18. 71. The HTSC of claim 70, wherein x = 0.12 ± 0.04. 72. A wire, tape, thin film, coated conductor, bulk material or any other conductor comprising the material of claims 37-71.