Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

We propose that physical properties for the high temperature superconductors can be addressed by either a two-dimensional planar hole-doping concentration (P-pl) or an effective three-dimensional hole-doping concentration (P-3D), We find that superconducting transition temperature (T-c) exhibits a universal dome-shaped behavior in the T,, vs. P-3D plot with a universal optimal doping concentration at P-3D similar to 1.6 x 10(21) cm(-3) for the single-layer high temperature superconductors. (c) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physc.2007.04.079

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The effect of hydrostatic pressure up to 2 GPa on the superconductiong transitions in (formula presented) is investigated. The ambient- and high-pressure properties of two series of samples with (formula presented) and 0.015 and (formula presented) are characterized and compared by ac-susceptibility measurements. At ambient pressure both sets of samples fit into the same phase diagram as a function of the total hole concentration (formula presented) For (formula presented) there is a single superconducting transition (formula presented) with an unusually large pressure coefficient, (formula presented) At a higher hole density (formula presented) a second superconducting transition (formula presented) follows the first transition upon cooling and the pressure shift of this transition is negative, (formula presented) At the boundary as the hole density is close to 0.085 the phase separation can be induced by pressure. The results are explained in terms of a strong correlation of the interstitial oxygen with the hole system in the CuO planes. Pressure, applied at ambient temperature, causes a redistribution of holes. The mobile oxygen dopants follow and enhance (formula presented) as well as the tendency toward phase separation. If pressure is changed at low temperature (formula presented) the effects on (formula presented) and phase separations are greatly diminished because the interstitial oxygen becomes immobile at low T. Our results indicate that the dopant effects are important. Dopants and holes should be treated as a single globally correlated state. When thermodynamic euqilibrium is approached in the oxygen-doped samples, we find that there is an intrinsic tendency of electronic phase separation of doped holes into two distinct superconducting states. © 2002 The American Physical Society.

DOI： 10.1103/PhysRevB.65.144522

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We have analyzed various characteristic temperatures and energies of hole-doped high- Tc cuprates as a function of a dimensionless hole-doping concentration (pu). Entirely based on the experimental grounds, we construct a unified electronic phase diagram (UEPD), where three characteristic temperatures (T 's) and their corresponding energies (E 's) converge as pu increases in the underdoped regime. T 's and E 's merge together with the Tc curve and 3.5 kB Tc curve at pu ∼1.1 in the overdoped regime, respectively. They finally go to zero at pu ∼1.3. The UEPD follows an asymmetric half-dome-shaped Tc curve, in which Tc appears at pu ∼0.4, reaches a maximum at pu ∼1, and rapidly goes to zero at pu ∼1.3. The asymmetric half-dome-shaped Tc curve is at odds with the well-known symmetric superconducting dome for La2-x Srx CuO4 (SrD-La214), in which two characteristic temperatures and energies converge as pu increases and merge together at pu ∼1.6, where Tc goes to zero. The UEPD clearly shows that pseudogap phase precedes and coexists with high temperature superconductivity in the underdoped and overdoped regimes, respectively. It is also clearly seen that the upper limit of high- Tc cuprate physics ends at a hole concentration that equals to 1.3 times the optimal doping concentration for almost all high- Tc cuprate materials and 1.6 times the optimal doping concentration for the SrD-La214. Our analysis strongly suggests that pseudogap is a precursor of high- Tc superconductivity, the observed quantum critical point inside the superconducting dome may be related to the end point of UEPD, and the normal state of the underdoped and overdoped high temperature superconductors cannot be regarded as a conventional Fermi liquid phase. © 2008 The American Physical Society.

DOI： 10.1103/PhysRevB.77.184520

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We have analyzed various characteristic temperatures and energies of hole-doped high- Tc cuprates as a function of a dimensionless hole-doping concentration (pu). Entirely based on the experimental grounds, we construct a unified electronic phase diagram (UEPD), where three characteristic temperatures (T 's) and their corresponding energies (E 's) converge as pu increases in the underdoped regime. T 's and E 's merge together with the Tc curve and 3.5 kB Tc curve at pu ∼1.1 in the overdoped regime, respectively. They finally go to zero at pu ∼1.3. The UEPD follows an asymmetric half-dome-shaped Tc curve, in which Tc appears at pu ∼0.4, reaches a maximum at pu ∼1, and rapidly goes to zero at pu ∼1.3. The asymmetric half-dome-shaped Tc curve is at odds with the well-known symmetric superconducting dome for La2-x Srx CuO4 (SrD-La214), in which two characteristic temperatures and energies converge as pu increases and merge together at pu ∼1.6, where Tc goes to zero. The UEPD clearly shows that pseudogap phase precedes and coexists with high temperature superconductivity in the underdoped and overdoped regimes, respectively. It is also clearly seen that the upper limit of high- Tc cuprate physics ends at a hole concentration that equals to 1.3 times the optimal doping concentration for almost all high- Tc cuprate materials and 1.6 times the optimal doping concentration for the SrD-La214. Our analysis strongly suggests that pseudogap is a precursor of high- Tc superconductivity, the observed quantum critical point inside the superconducting dome may be related to the end point of UEPD, and the normal state of the underdoped and overdoped high temperature superconductors cannot be regarded as a conventional Fermi liquid phase. © 2008 The American Physical Society.

DOI： 10.1103/PhysRevB.77.184520

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Language：English   Publisher：AMERICAN PHYSICAL SOC  

We study superconducting transition temperature (T-c) of oxygen-doped double-layer high-temperature superconductors YBa2Cu3O6+delta (0 <=delta <= 1) as a function of the oxygen dopant concentration (delta) and planar hole-doping concentration (P-pl). We find that T-c, while clearly influenced by the development of the chain ordering as seen in the T-c vs delta plot, lies on a universal curve originating at the critical hole concentration (P-c)=1/16 in the T-c vs P-pl plot. Our analysis suggests that the universal behavior of T-c(P-pl) can be understood in terms of the competition and collaboration of chemical phases and electronic phases that exist in the system. We conclude that the global superconductivity behavior of YBa2Cu3O6+delta as a function of doping is electronically driven and dictated by pristine electronic phases at magic doping numbers that follow the hierarchical order based on P-c, such as 2xP(c), 3xP(c), and 4xP(c). We find that there are at least two intrinsic electronic superconducting phases of T-c=60 K at 2xP(c)=1/8 and T-c=90 K at 3xP(c)=3/16.

DOI： 10.1103/PhysRevB.75.012508

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Language：English   Publisher：AMERICAN PHYSICAL SOC  

We study superconducting transition temperature (T-c) of oxygen-doped double-layer high-temperature superconductors YBa2Cu3O6+delta (0 <=delta <= 1) as a function of the oxygen dopant concentration (delta) and planar hole-doping concentration (P-pl). We find that T-c, while clearly influenced by the development of the chain ordering as seen in the T-c vs delta plot, lies on a universal curve originating at the critical hole concentration (P-c)=1/16 in the T-c vs P-pl plot. Our analysis suggests that the universal behavior of T-c(P-pl) can be understood in terms of the competition and collaboration of chemical phases and electronic phases that exist in the system. We conclude that the global superconductivity behavior of YBa2Cu3O6+delta as a function of doping is electronically driven and dictated by pristine electronic phases at magic doping numbers that follow the hierarchical order based on P-c, such as 2xP(c), 3xP(c), and 4xP(c). We find that there are at least two intrinsic electronic superconducting phases of T-c=60 K at 2xP(c)=1/8 and T-c=90 K at 3xP(c)=3/16.

DOI： 10.1103/PhysRevB.75.012508

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Language：English   Publisher：IOP PUBLISHING LTD  

We argue that in cuprate physics there are two types, hole content per CuO2 plane ( P-p1) and the corresponding hole content per unit volume ( P-3D), of hole-doping concentrations for addressing physical properties that are two dimensional ( 2D) and three dimensional ( 3D) in nature, respectively. We find that the superconducting transition temperature ( T-c) varies systematically with P-3D as a superconducting 'dome' with a universal optimal hole-doping concentration of P opt 3D = 1.6 x 10(21) cm(-3) for single-layer high-temperature superconductors. We suggest that P opt 3D determines the upper bound of the electronic energy of underdoped single-layer high-T-c cuprates.

DOI： 10.1088/0953-2048/19/9/004

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We argue that in cuprate physics there are two types, hole content per CuO2 plane ( P-p1) and the corresponding hole content per unit volume ( P-3D), of hole-doping concentrations for addressing physical properties that are two dimensional ( 2D) and three dimensional ( 3D) in nature, respectively. We find that the superconducting transition temperature ( T-c) varies systematically with P-3D as a superconducting 'dome' with a universal optimal hole-doping concentration of P opt 3D = 1.6 x 10(21) cm(-3) for single-layer high-temperature superconductors. We suggest that P opt 3D determines the upper bound of the electronic energy of underdoped single-layer high-T-c cuprates.

DOI： 10.1088/0953-2048/19/9/004

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DOI： 10.1088/0953-2048/19/9/004

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We have measured thermoelectric power (TEP) as a function of hole concentration per CuO2 layer P-pl in Y1-xCaxBa2Cu3O6 (P-pl=x/2) with no oxygen in the Cu-O chain layer. The room-temperature TEP as a function of P-pl, S-290(P-pl), of Y1-xCaxBa2Cu3O6 behaves identically to that of La2-zSrzCuO4 (P-pl=z). We argue that S-290(P-pl) represents a measure of the intrinsic equilibrium electronic states of doped holes and, therefore, can be used as a common scale for the carrier concentrations of layered cuprates. We shows that the P-pl determined by this new universal scale is consistent with both hole concentration microscopically determined by NQR and the hole concentration macroscopically determined by the formal valency of Cu. We find two characteristic scaling temperatures, T-S(*) and T-S2(*), in the TEP versus temperature curves that change systematically with doping. Based on the universal scale, we uncover a universal phase diagram in which almost all the experimentally determined pseudogap temperatures as a function of P-pl fall on two common curves; lower pseudogap temperature defined by the T-S(*) versus P-pl curve and upper pseudogap temperature defined by the T-S2(*) versus P-pl curve. We find that while pseudogaps are intrinsic properties of doped holes of a single CuO2 layer for all high-T-c cuprates, T-c depends on the number of layers, therefore, the inter layer coupling, in each individual system.

DOI： 10.1103/PhysRevB.70.214517

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Language：English   Publisher：AMERICAN PHYSICAL SOC  

We have measured thermoelectric power (TEP) as a function of hole concentration per CuO2 layer P-pl in Y1-xCaxBa2Cu3O6 (P-pl=x/2) with no oxygen in the Cu-O chain layer. The room-temperature TEP as a function of P-pl, S-290(P-pl), of Y1-xCaxBa2Cu3O6 behaves identically to that of La2-zSrzCuO4 (P-pl=z). We argue that S-290(P-pl) represents a measure of the intrinsic equilibrium electronic states of doped holes and, therefore, can be used as a common scale for the carrier concentrations of layered cuprates. We shows that the P-pl determined by this new universal scale is consistent with both hole concentration microscopically determined by NQR and the hole concentration macroscopically determined by the formal valency of Cu. We find two characteristic scaling temperatures, T-S(*) and T-S2(*), in the TEP versus temperature curves that change systematically with doping. Based on the universal scale, we uncover a universal phase diagram in which almost all the experimentally determined pseudogap temperatures as a function of P-pl fall on two common curves; lower pseudogap temperature defined by the T-S(*) versus P-pl curve and upper pseudogap temperature defined by the T-S2(*) versus P-pl curve. We find that while pseudogaps are intrinsic properties of doped holes of a single CuO2 layer for all high-T-c cuprates, T-c depends on the number of layers, therefore, the inter layer coupling, in each individual system.

DOI： 10.1103/PhysRevB.70.214517

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Language：English   Publisher：ELSEVIER SCIENCE BV  

Room-temperature thermoelectric power S-290 as a function of hole concentration per planer Cu atom (P-pl) has been studied in a chain-free double-layer Y1-xCaxBa2Cu3O6. S-290 (P-p1) of Y1-xCa2Ba2Cu3O6 (P-pl = x/2) behaves identically to that of single-layer La2-xSrxCuO4 (P-pl = x). In order to show the validity of the present scale of S-290(P-pl), we demonstrate the phase diagram for bilayer YBa2Cu3Oy system and Bi2Sr2CaCu2Oy system and discuss. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physc.2004.03.103

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Room-temperature thermoelectric power S-290 as a function of hole concentration per planer Cu atom (P-pl) has been studied in a chain-free double-layer Y1-xCaxBa2Cu3O6. S-290 (P-p1) of Y1-xCa2Ba2Cu3O6 (P-pl = x/2) behaves identically to that of single-layer La2-xSrxCuO4 (P-pl = x). In order to show the validity of the present scale of S-290(P-pl), we demonstrate the phase diagram for bilayer YBa2Cu3Oy system and Bi2Sr2CaCu2Oy system and discuss. (C) 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.physc.2004.03.103

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In an Y0.83Ca0.17Ba2Cu3O6 polycrystalline sample, under thermal cycling below 16 K, an unusual relaxation effect of the superconducting resistive transition has been observed after the pressure is changed at RT. The normal-state resistivity does not change. Since there is no mobile oxygen in the present sample, the effect of oxygen rearrangement can be ignored. The observed results can be understood by the charge redistribution within the CuO2 planes. (C) 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4534(02)02513-3

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Language：English   Publisher：ELSEVIER SCIENCE BV  

In an Y0.83Ca0.17Ba2Cu3O6 polycrystalline sample, under thermal cycling below 16 K, an unusual relaxation effect of the superconducting resistive transition has been observed after the pressure is changed at RT. The normal-state resistivity does not change. Since there is no mobile oxygen in the present sample, the effect of oxygen rearrangement can be ignored. The observed results can be understood by the charge redistribution within the CuO2 planes. (C) 2003 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0921-4534(02)02513-3

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The effect of hydrostatic pressure up to 2 GPa on the superconductiong transitions in La2-xSrxCuO4+delta is investigated. The ambient- and high-pressure properties of two series of samples with x=0 and 0.015 and 0<δ<0.1 are characterized and compared by ac-susceptibility measurements. At ambient pressure both sets of samples fit into the same phase diagram as a function of the total hole concentration n(h). For n(h)<0.085 there is a single superconducting transition (T-c≈30 K) with an unusually large pressure coefficient, dT(c)((30))/dpapproximate to10 K/GPa. At a higher hole density (n(h)>0.085) a second superconducting transition (T(c)approximate to15 K) follows the first transition upon cooling and the pressure shift of this transition is negative, dT(c)((15))/dpapproximate to-4 K/GPa. At the boundary as the hole density is close to 0.085 the phase separation can be induced by pressure. The results are explained in terms of a strong correlation of the interstitial oxygen with the hole system in the CuO planes. Pressure, applied at ambient temperature, causes a redistribution of holes. The mobile oxygen dopants follow and enhance T-c as well as the tendency toward phase separation. If pressure is changed at low temperature (<100 K) the effects on T-c and phase separations are greatly diminished because the interstitial oxygen becomes immobile at low T. Our results indicate that the dopant effects are important. Dopants and holes should be treated as a single globally correlated state. When thermodynamic euqilibrium is approached in the oxygen-doped samples, we find that there is an intrinsic tendency of electronic phase separation of doped holes into two distinct superconducting states.

DOI： 10.1103/PhysRevB.65.144522

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Language：English   Publisher：AMERICAN PHYSICAL SOC  

The effect of hydrostatic pressure up to 2 GPa on the superconductiong transitions in La2-xSrxCuO4+delta is investigated. The ambient- and high-pressure properties of two series of samples with x=0 and 0.015 and 0<δ<0.1 are characterized and compared by ac-susceptibility measurements. At ambient pressure both sets of samples fit into the same phase diagram as a function of the total hole concentration n(h). For n(h)<0.085 there is a single superconducting transition (T-c≈30 K) with an unusually large pressure coefficient, dT(c)((30))/dpapproximate to10 K/GPa. At a higher hole density (n(h)>0.085) a second superconducting transition (T(c)approximate to15 K) follows the first transition upon cooling and the pressure shift of this transition is negative, dT(c)((15))/dpapproximate to-4 K/GPa. At the boundary as the hole density is close to 0.085 the phase separation can be induced by pressure. The results are explained in terms of a strong correlation of the interstitial oxygen with the hole system in the CuO planes. Pressure, applied at ambient temperature, causes a redistribution of holes. The mobile oxygen dopants follow and enhance T-c as well as the tendency toward phase separation. If pressure is changed at low temperature (<100 K) the effects on T-c and phase separations are greatly diminished because the interstitial oxygen becomes immobile at low T. Our results indicate that the dopant effects are important. Dopants and holes should be treated as a single globally correlated state. When thermodynamic euqilibrium is approached in the oxygen-doped samples, we find that there is an intrinsic tendency of electronic phase separation of doped holes into two distinct superconducting states.

DOI： 10.1103/PhysRevB.65.144522

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Language：English   Publisher：AMER PHYSICAL SOC  

The pressure effect on the Hall coefficient R-H has been studied in Ca and oxygen co-doped Y1-xCaxBa2Cu3O, systems. R-H is not altered by pressure in samples without a Cu-O chain, whereas samples with an oxygen-deficient chain are altered in response to pressure, thus demonstrating the contribution of the oxygen reordering effect. However, even in samples with full chain ordering. R-H changes at a rate of -8.3%/GPa. This suggests the contribution of internal strain due to the presence of a Cu-O chain structure. We independently estimated the effect of two factors, oxygen reordering and internal strain, on the pressure effect on R-H. The oxygen-content dependence of the pressure effect on R-H can be explained by competition between oxygen reordering and internal strain.

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Language：English   Publisher：AMER PHYSICAL SOC  

The pressure effect on the Hall coefficient R-H has been studied in Ca and oxygen co-doped Y1-xCaxBa2Cu3O, systems. R-H is not altered by pressure in samples without a Cu-O chain, whereas samples with an oxygen-deficient chain are altered in response to pressure, thus demonstrating the contribution of the oxygen reordering effect. However, even in samples with full chain ordering. R-H changes at a rate of -8.3%/GPa. This suggests the contribution of internal strain due to the presence of a Cu-O chain structure. We independently estimated the effect of two factors, oxygen reordering and internal strain, on the pressure effect on R-H. The oxygen-content dependence of the pressure effect on R-H can be explained by competition between oxygen reordering and internal strain.

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Language：English   Publisher：SPRINGER  

The pressure effect on the superconducting transitions in La2-xSrxCuO4+delta is investigated by ac susceptibility measurements up to 2 GPa. Two series of samples with x=0 and x=0.015 and 0<delta<0.11 are compared with respect to the ambient and high pressure properties. At ambient pressure both sets of samples fit into the same phase diagram as a function of the total hole concentration (Sr- and oxygen doping contribute to the total carrier density, p). A single superconducting transition (T(c)approximate to30 K) for p<0.085 splits into two transitions (T(c)approximate to15 K and 30 K) at higher hole density indicating that electronic phase separation sets in above p=0.085. The pressure effect on T-c of the 3 0 K transition is unusually large, dT(c)((30))/dPapproximate to10 K/GPa. The electronic phase separation at higher hole density is enhanced by pressure and T-c of the 15 K superconducting state exhibits a negative Pressure shift, dT(c)((15))/dPapproximate to-4 K/GPa. At a hole density close to 0.085 the electronic phase separation into the two superconducting states can be induced by pressure. The results are interpreted in terms of a strong correlation of the hole system and the interstitial (mobile) oxygen ions. Pressure, applied at ambient temperature, causes a redistribution of holes and oxygen and enhances superconductivity (T-c) as well as the tendency to phase separation.

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Language：English   Publisher：SPRINGER  

The pressure effect on the superconducting transitions in La2-xSrxCuO4+delta is investigated by ac susceptibility measurements up to 2 GPa. Two series of samples with x=0 and x=0.015 and 0<delta<0.11 are compared with respect to the ambient and high pressure properties. At ambient pressure both sets of samples fit into the same phase diagram as a function of the total hole concentration (Sr- and oxygen doping contribute to the total carrier density, p). A single superconducting transition (T(c)approximate to30 K) for p<0.085 splits into two transitions (T(c)approximate to15 K and 30 K) at higher hole density indicating that electronic phase separation sets in above p=0.085. The pressure effect on T-c of the 3 0 K transition is unusually large, dT(c)((30))/dPapproximate to10 K/GPa. The electronic phase separation at higher hole density is enhanced by pressure and T-c of the 15 K superconducting state exhibits a negative Pressure shift, dT(c)((15))/dPapproximate to-4 K/GPa. At a hole density close to 0.085 the electronic phase separation into the two superconducting states can be induced by pressure. The results are interpreted in terms of a strong correlation of the hole system and the interstitial (mobile) oxygen ions. Pressure, applied at ambient temperature, causes a redistribution of holes and oxygen and enhances superconductivity (T-c) as well as the tendency to phase separation.

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In Y0.83Ca0.17Ba2Cu3O6 two superconducting transitions have been observed under high pressure; the pressure-induced superconductivity at the lower-T and the pressure-enhanced one at the higher-T. The former is the filamentary superconductivity induced by pressure. The origin of the latter is attributed to the charge redistribution induced by pressure.

DOI： 10.1016/S0921-4534(00)00572-4

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Unusual pressure-induced broadening of superconducting transition was observed in La1.916Sr0.084CuO4 without excess oxygen by ac resistance measurement (acR) and mutual inductance measurement (acM). Above similar to 9kbar, a negative dT(c)/dP determined by acM and a positive dT(c)/dP determined by acR are observed, while below similar to 9 kbar, both dT(c)/dP are positive in sign and identical in magnitude. This suggests the occurrence of the intralayer charge redistribution induced by pressure.

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In this report, Ca-doped Pr-123 compounds have been synthesized under high pressure and the highest T-c up to 115K is achieved in Pr0.5Ca0.5Ba2Cu3Oy According to the X-ray analysis and thermal-electric power data, the Ca-ions induced carriers and reduced occupation of Pr ion in Ba site. These two effects could be the reason for the occurrence of superconductivity with higher T-c. Also, magnetic susceptibility under high pressure has been carried out by ac mutual inductance measurements. It showed that T-c increased linearly with pressure at dT(c)/dP =-+0.10 K/kbar up to 20 kbar. The pressure effect could be explained by carrier increase due to the shorter distance between Ca ion and CuO2 plane.

DOI： 10.1016/S0921-4534(00)00504-9

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In this report, Ca-doped Pr-123 compounds have been synthesized under high pressure and the highest T-c up to 115K is achieved in Pr0.5Ca0.5Ba2Cu3Oy According to the X-ray analysis and thermal-electric power data, the Ca-ions induced carriers and reduced occupation of Pr ion in Ba site. These two effects could be the reason for the occurrence of superconductivity with higher T-c. Also, magnetic susceptibility under high pressure has been carried out by ac mutual inductance measurements. It showed that T-c increased linearly with pressure at dT(c)/dP =-+0.10 K/kbar up to 20 kbar. The pressure effect could be explained by carrier increase due to the shorter distance between Ca ion and CuO2 plane.

DOI： 10.1016/S0921-4534(00)00504-9

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Unusual pressure-induced broadening of superconducting transition was observed in La1.916Sr0.084CuO4 without excess oxygen by ac resistance measurement (acR) and mutual inductance measurement (acM). Above similar to 9kbar, a negative dT(c)/dP determined by acM and a positive dT(c)/dP determined by acR are observed, while below similar to 9 kbar, both dT(c)/dP are positive in sign and identical in magnitude. This suggests the occurrence of the intralayer charge redistribution induced by pressure.

DOI： 10.1016/S0921-4534(00)01396-4

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Pressure effect on Hall coefficient, RH has been investigated in Y1-xCaxBa2Cu3Oy system with and without Cu-O chain structure, which is known as a charge reservoir. In the samples with Cu-O chain (y≠6), it was found that RH changes by pressure. But, in the samples without Cu-O chain (y=6), it was found that RH does not change by pressure. It is concluded that a source of the pressure-induced mobile carrier is the Cu-O chain structure in Y1-xCaxBa2Cu3Oy system. [high-Tc superconductor, Hall coefficient, Cu-O chain structure, oxygen-content, lattice parameter]. © 1998, The Japan Society of High Pressure Science and Technology. All rights reserved.

DOI： 10.4131/jshpreview.7.580

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Pressure effect on Hall coefficient, RH has been investigated in Y1-xCaxBa2Cu3Oy system with and without Cu-O chain structure, which is known as a charge reservoir. In the samples with Cu-O chain (y≠6), it was found that RH changes by pressure. But, in the samples without Cu-O chain (y=6), it was found that RH does not change by pressure. It is concluded that a source of the pressure-induced mobile carrier is the Cu-O chain structure in Y1-xCaxBa2Cu3Oy system. [high-Tc superconductor, Hall coefficient, Cu-O chain structure, oxygen-content, lattice parameter]. © 1998, The Japan Society of High Pressure Science and Technology. All rights reserved.

DOI： 10.4131/jshpreview.7.580

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Pressure effect on Hall coefficient, R-H was investigated in Y0.9Ca0.1Ba2Cu3Oy (6.72 less than or equal to y less than or equal to 6.98) samples with Cu-O chain structure and Y1-xCaxBa2Cu3Oy (y=6) samples without Cu-O chain structure. it is found that the Cu-O chain structure is a source of the pressure-induced mobile carrier.

DOI： 10.1016/S0921-4534(97)00415-2

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Language：English   Publisher：Elsevier  

Pressure effect on Hall coefficient, RH was investigated in Y0.9Ca0.1Ba2Cu3Oy (6.72≤y≤6.98) samples with Cu-O chain structure and Y1-xCaxBa2Cu3Oy (y=6) samples without Cu-O chain structure. It is found that the Cu-O chain structure is a source of the pressure-induced mobile carrier.

DOI： 10.1016/S0921-4534(97)00415-2

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Language：English   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The dependence of the superconducting transition temperature Tc On the Hall number was systematically investigated by changing the oxygen content and pressure in Y0.9Ca0.1Ba2Cu3O(3). It was determined that the change in Tc due to pressure, Delta Tc, can be expressed by sum of two terms, (Delta Tc)c and (Delta Tc)p, where (Delta Tc)c is the change in Tc due to pressure-induced change in carrier density and (Delta Tc)p is the change in Tc due to pressure-enhanced electron pairing. The contribution of (Delta Tc)c to Delta Tc increases with decreasing oxygen content. This result is discussed in terms of whether oxygen atoms in the carrier reservoir can be easily moved by changing the temperature and/or pressure.

DOI： 10.1016/0038-1098(96)00071-3

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The dependence of the superconducting transition temperature Tc on the Hall number was systematically investigated by changing the oxygen content and pressure in Y0.9Ca0.1Ba2Cu3Oy. It was determined that the change in Tc due to pressure, ΔTc, can be expressed by sum of two terms, (ΔTc)c and (ΔTc)p, where (ΔTc)c is the change in Tc due to pressure-induced change in carrier density and (ΔTc)P is the change in Tc due to pressure-enhanced electron pairing. The contribution of (ΔTc)c to ΔTc increases with decreasing oxygen content. This result is discussed in terms of whether oxygen atoms in the carrier reservoir can be easily moved by changing the temperature and/or pressure.

DOI： 10.1016/0038-1098(96)00071-3

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Language：English   Publisher：CZECHOSLOVAK JNL OF PHYSICS  

Pressure effect on Hall coefficient RH was investigated in Y1-xCaxBa2Cu3O6 (x=0.15 and 0.20) without Cu-O chain. No change in RH was observed under pressure up to 12kbar; no pressure-induced change occurs in the carrier density. The pressure-induced change in the carrier density does not occur when the oxygen atoms in the Cu-O chain is hard to displace by annealing or applying pressure.

DOI： 10.1007/BF02562810

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Hall coefficient R(H) and superconducting transition temperature T-c in Y0.9Ca0.1Ba2Cu3Oy with 6.59 less than or equal to y less than or equal to 7.01 have been measured under ambient pressure and under high pressure up to 2GPa. It is found that the relation of T-c and Hall number 1/eR(H) under high pressure is explained in terms of the change in the carrier density and the pressure-induced pairing effect which depends on the oxygen-content.

DOI： 10.1016/0921-4534(94)91953-4

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Hall coefficient R(H) and superconducting transition temperature T-c in Y0.9Ca0.1Ba2Cu3Oy with 6.59 less than or equal to y less than or equal to 7.01 have been measured under ambient pressure and under high pressure up to 2GPa. It is found that the relation of T-c and Hall number 1/eR(H) under high pressure is explained in terms of the change in the carrier density and the pressure-induced pairing effect which depends on the oxygen-content.

DOI： 10.1016/0921-4534(94)91953-4

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Resistivity and Hall coefficient of Y1-xCaxBa2Cu3Oy (YCBCO) were measured and analyzed by a simple two-carrier model involving holes and electrons. The experimental results are reproduced well, and the carrier concentration and mobility estimated from the model are reasonable values in physics. The data of Tl2Ba2CuOy measured by Kubo et al. also were analyzed by the same model and the result was compared with that of YCBCO. In both systems, the properties of electron carrier remarkably change for hole-doping compared with those of hole carrier.

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The anisotropic resistivity in the a-b plane and Hall coefficient have been measured in a single-crystal Bi2Sr2CaCu2O(y) (BSCCO) and their temperature dependences have been analyzed by a two-band model involving holes and electrons. It is confirmed that the calculated values of the resistivities and Hall coefficient reproduce well the data and the carrier concentrations, mobilities and mean-free-paths obtained from the model are reasonable values in physics. It is found that the hole concentration is smaller than the electron one, but the hole mobility is larger than the electron one. The transport properties of BSCCO are discussed in terms of two types of the hole and electron carrier.

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The anisotropic resistivity in the a-b plane and Hall coefficient have been measured in a single-crystal Bi2Sr2CaCu2O(y) (BSCCO) and their temperature dependences have been analyzed by a two-band model involving holes and electrons. It is confirmed that the calculated values of the resistivities and Hall coefficient reproduce well the data and the carrier concentrations, mobilities and mean-free-paths obtained from the model are reasonable values in physics. It is found that the hole concentration is smaller than the electron one, but the hole mobility is larger than the electron one. The transport properties of BSCCO are discussed in terms of two types of the hole and electron carrier.

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Language：English   Publisher：ELSEVIER SCIENCE BV  

Web of Science

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Language：English   Publisher：ELSEVIER SCIENCE BV  

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Language：Japanese   Publisher：The Physical Society of Japan (JPS)  

CiNii Books

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Event date： 2007.9

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2006.9

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2006.6

Language：English   Presentation type：Oral presentation (general)  

Venue：Dresden (Germany)  

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Event date： 2004.4

Language：Japanese   Presentation type：Oral presentation (general)  

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Event date： 2003.5

Language：English   Presentation type：Poster presentation  

Venue：Rio de Janeiro (Brazil)  

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Event date： 2002.9

Language：Japanese   Presentation type：Poster presentation  

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Event date： 2002.8

Language：English   Presentation type：Poster presentation  

Venue：Hiroshima (Japan)  

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Event date： 2001.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：八王子市  

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Event date： 2000.2

Language：English   Presentation type：Poster presentation  

Venue：Houston (USA)  

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Event date： 2000.2

Language：English   Presentation type：Poster presentation  

Venue：Houston (USA)  

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Event date： 2000.2

Language：English   Presentation type：Poster presentation  

Venue：Houston (USA)  

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Event date： 1998.3

Language：Japanese   Presentation type：Poster presentation  

Venue：船橋市  

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Event date： 1997.10

Language：Japanese   Presentation type：Poster presentation  

Venue：神戸市  

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Event date： 1997.8

Language：English   Presentation type：Poster presentation  

Venue：京都市  

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Event date： 1997.2 - 1997.3

Language：English   Presentation type：Poster presentation  

Venue：Beijing (China)  

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Event date： 1996.10

Language：English   Presentation type：Poster presentation  

Venue：札幌市  

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Event date： 1996.8

Language：English   Presentation type：Poster presentation  

Venue：Prague (Czech)  

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Event date： 1995.9

Language：Japanese   Presentation type：Poster presentation  

Venue：堺市  

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Event date： 1994.7

Language：English   Presentation type：Poster presentation  

Venue：Grenoble (France)  

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Event date： 1994.7

Language：English   Presentation type：Poster presentation  

Venue：Grenoble (France)  

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Event date： 1993.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：仙台市  

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