Correlation between hole concentration and Tc in (La2−xYx)Ba2(CayCu4+y)Oz superconductors

Kuberkar, D. G.; Subbarao, M. V.; Joshi, Amish G.; Kulkarni, R.G.

doi:10.1016/s0921-4526(98)00688-7

Cited by 3 publications

(4 citation statements)

References 3 publications

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“…Nd 0.5 Ca 1 Ba 2 (Cu 1-x Mo x ) 5 O z samples are similar to the XRD patterns of La-2125 compounds[1,2]. The lattice parameters, obtained from a least-square refinement of the d values observed from the X-ray diffractogram, are shown in Figure1as a function of Mo concentration.…”

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confidence: 68%

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Effect of Mo-substitution on superconductivity, flux pinning and critical currents of La1.5Nd0.5Ca1Ba2Cu5Oz

Rayaprol¹,

Mavani²,

Thaker³

et al. 2003

Physica C: Superconductivity

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Mo-substituted triple perovskite superconducting samples with stoichiometric composition La 1.5 Nd 0.5 Ca 1 Ba 2 (Cu 1-x Mo x ) 5 O z with x = 0.00, 0.01, 0.03, 0.05 and 0.10, have been investigated using X-ray diffraction, electrical resistivity, magnetic susceptibility and Magnetization measurements. Oxygen content has also been determined by the iodometric technique. The observed reduction in superconducting transition temperature, T c , in this system with increasing Mo content can be attributed to the decrease in hole concentration. Magnetization measurements as a function of temperature and field (H), exhibit an M-H hysteresis loop which indicates moderate flux pinning, which is thought due to pinning centers created by Mo substitution at Cu sites. The critical current density, J c , deduced from the M-H data satisfies the flux creep model.

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supporting

confidence: 68%

“…The superconducting system La 1.5 R 0.5 Ca 1 Ba 2 Cu 5 O z with R = rare earth (abbreviated as La-2125) has been extensively studied by our group [1,2]. La-2125 has a triple perovskite structure similar to that of the tetragonal La 2.5 R 0.5 Ca 1 Ba 3 Cu 7 O z (La-3137) [3] and a superconducting transition temperature (T c ) of ~78 K. Both…”

Section: Introductionmentioning

confidence: 99%

Effect of Mo-substitution on superconductivity, flux pinning and critical currents of La1.5Nd0.5Ca1Ba2Cu5Oz

Rayaprol¹,

Mavani²,

Thaker³

et al. 2003

Physica C: Superconductivity

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“…3,4 Structural and superconducting studies on La 2Ϫx R x Ca y Ba 2 Cu 4ϩy O z ͑yϭ2x, and 0.0ϽxϽ0.5͒ reveal that all these are single phase materials crystallizing in a tetragonal structure and T c increases with increasing Ca concentration in Ref. 5.…”

Section: Introductionmentioning

confidence: 98%

Structural and superconducting properties of La2−xRxBa2CayCu4+yO10+δ (R=Nd, Gd; y=2x) system

Kuberkar

Thampi

Shah

et al. 2001

Journal of Applied Physics

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A nonsuperconducting La2Ba2Cu4O9+δ system has been made superconducting by the addition of CaCuO2, along with rare earth doping at the La site, with the stoichiometric composition La2−xRxCayBa2Cu4+yO10+δ (R=Nd, Gd, and y=2x). All the samples with 0.0<x<0.5; y=2x were characterized by x-ray diffraction and neutron diffraction measurements for structural properties and by ac susceptibility, dc resistivity, and iodometric analysis for superconducting properties. The x=0.0 sample displays semiconducting behavior. Increasing x increases Tc from less than 15 K for Nd/Gd samples with x=0.1 to ∼78 K for x=0.5 samples. It is interesting to note that the hole concentration and Tc exhibit a strong correlation with increasing dopant concentration. Neutron diffraction studies confirm the occupancy of Ca and Nd ions at the La site with a concomitant displacement of La on to the Ba site.

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“…Consequently, many groups have reported that in the 80 K phase of Bi 2 Sr 2 CaCu 2 O 8+y superconductors, the substitution of trivalent Y and other elements with different valencies, for the divalent Ca, causes a drastic decrease in the carrier concentration. Furthermore, a transition from superconductor to insulator occurs due to the decrease in carrier concentration [15][16][17][18][19][20][21][22][23][24]. In the 110 K phase, however, there have been few reports of measurements using substitution at the Ca site to test the effect of carrier concentration on the superconducting properties.…”

Section: Introductionmentioning

confidence: 99%

Effect of Nd substitution for the Ca site in the 110 K phase of (Bi,Pb)$ndash$Sr$ndash$Ca$ndash$Cu$ndash$O superconductors

Lee

Song

2002

Supercond. Sci. Technol.

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The effect of substitution of trivalent Nd ions for divalent Ca ions has been studied in the 110 K phase of Bi 1.84 Pb 0.34 Sr 1.91 (Ca 1-x Nd x ) 2.03 Cu 3.06 O 10+y (x = 0-0.1). We found the solubility limit of Nd in the 110 K phase to be around x < 0.015. Within the solubility limit, the c-axis seemed to decrease with increasing x. In the region of the 110 K single phase, the critical temperature T c gradually decreased with an increase in x, corresponding to a small change of the carrier concentration.

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Correlation between hole concentration and Tc in (La2−xYx)Ba2(CayCu4+y)Oz superconductors

Cited by 3 publications

References 3 publications

Effect of Mo-substitution on superconductivity, flux pinning and critical currents of La1.5Nd0.5Ca1Ba2Cu5Oz

Effect of Mo-substitution on superconductivity, flux pinning and critical currents of La1.5Nd0.5Ca1Ba2Cu5Oz

Structural and superconducting properties of La2−xRxBa2CayCu4+yO10+δ (R=Nd, Gd; y=2x) system

Effect of Nd substitution for the Ca site in the 110 K phase of (Bi,Pb)$ndash$Sr$ndash$Ca$ndash$Cu$ndash$O superconductors

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