scholarly journals IMPACT OF Zn SUBSTITUTION ON PHASE FORMATION AND SUPERCONDUCTIVITY OF Bi1.6Pb0.4Sr2Ca2Cu3-xZnxO10-δ WITH x = 0.0, 0.015, 0.03, 0.06, 0.09 AND 0.12

2005 ◽  
Vol 19 (16) ◽  
pp. 771-778 ◽  
Author(s):  
R. B. SAXENA ◽  
RAJIV GIRI ◽  
V. P. S. AWANA ◽  
H. K. SINGH ◽  
M. A. ANSARI ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Transition Temperature ◽  
Lattice Parameter ◽  
Ac Magnetic Susceptibility ◽  
Critical Transition ◽  
Critical Transition Temperature ◽  
Reaction Route ◽  
Zn Doping ◽  
Zn Substitution ◽  
Solid State Reaction Route

Samples of series Bi 1.6 Pb 0.4 Sr 2 Ca 2 Cu 3-x Zn x O 10-δ with x = 0.0, 0.015, 0.03, 0.06, 0.09 and 0.12 are synthesized by solid-state reaction route. All the samples crystallize in tetragonal structure with majority (> 90%) of Bi -2223( Bi 2 Sr 2 Ca 2 Cu 3 O 10) phase (c-lattice parameter ~ 36 Å). The proportion of Bi -2223 phase decreases slightly with an increase in x. The lattice parameters a and c of main phase ( Bi -2223) do not change significantly with increasing x. Superconducting critical transition temperature (Tc) decreases with x as evidenced by both resistivity [ρ(T)] and ac magnetic susceptibility [χ(T)] measurements. Interestingly the decrement of Tc is not monotonic and the same saturates at around 96 K for x > 0.06. In fact Tc decreases fast (~ 10 K/at%) for x = 0.015 and 0.03 samples and later nearly saturates for higher x values. Present results of Zn doping in Bi -2223 system are compared with other Zn -doped HTSC (high temperature superconducting) systems, namely the RE -123 ( REBa 2 Cu 3 O 7) and La -214 (( La, Sr )2 CuO 4).

Correlation between oxygen excess density and critical transition temperature in superconducting Bi-2201, Bi-2212 and Bi-2223

2008 ◽  
Vol 63 (11-12) ◽  
pp. 1372-1375 ◽  
Author(s):  
H.P. Roeser ◽  
F. Hetfleisch ◽  
F.M. Huber ◽  
M.F. von Schoenermark ◽  
M. Stepper ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Critical Transition ◽  
Critical Transition Temperature ◽  
Excess Density ◽  
Oxygen Excess

Reformulation of pairing theory

1988 ◽  
Vol 02 (05) ◽  
pp. 1101-1105 ◽  
Author(s):  
Miklos GULACSI ◽  
Zsolt GULACSI
Keyword(s):  
Transition Temperature ◽  
Size Effect ◽  
Layer Thickness ◽  
Short Communication ◽  
Cooper Pairing ◽  
Two Dimensional ◽  
Critical Transition ◽  
Critical Transition Temperature ◽  
Quantum Size ◽  
Natural Way

The original Cooper pairing theory is reformulated for electrons confined in a layer. This analysis is motivated by the quasi-two-dimensional character of the oxidic superconductors, in case of which the extension of the initial (3D) Cooper framework is practically impossible. By considering the electrons moving in a flat box, due to quantum size effect the properties of these oxidic superconductors can be explained in a natural way. In this short communication we will concentrate to the variation of the critical transition temperature due to the layer thickness and to the number of conduction (Cu-O) planes. The results are confirmed by the experiment. This being an evidence for the presence of the charge confinement effect in the oxidic superconductors.

A link between critical transition temperature and the structure of superconducting

2008 ◽  
Vol 62 (12) ◽  
pp. 733-736 ◽  
Author(s):  
H.P. Roeser ◽  
F. Hetfleisch ◽  
F.M. Huber ◽  
M.F. von Schoenermark ◽  
M. Stepper ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Critical Transition ◽  
Critical Transition Temperature

scholarly journals Effect of Bi Substitution on Structural and AC Magnetic Susceptibility Properties of Nd1−xBixMnO3

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 521 ◽  
Author(s):  
Nurul Atiqah Azhar ◽  
Intan Solehah Ismail ◽  
Nur Baizura Mohamed ◽  
Azhan Hashim ◽  
Zakiah Mohamed
Keyword(s):  
Magnetic Susceptibility ◽  
Single Phase ◽  
Lattice Parameter ◽  
Ac Magnetic Susceptibility ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
Pbnm Space Group ◽  
Bi Doping ◽  
Stretching Vibration ◽  
Crystal Structural

This study synthesizes the neodymium-based manganites with Bi doping, Nd1−xBixMnO3 (x = 0, 0.25 and 0.50) using the solid-state reaction route. The crystal structural, morphological and magnetic properties were determined using X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and AC magnetic susceptibility. The Rietveld refinement confirmed that the compounds were in the single-phase orthorhombic structure of the NdMnO3 with Pbnm space group and lattice parameter b increased with doping from 5.5571 (x = 0) to 5.6787 (x = 0.5). FTIR spectra showed that absorption bands were located within the range of 550–600 cm−1, which corresponded to the Mn–O stretching vibration. FESEM exhibited homogenous compound. The AC magnetic susceptibility measurement studies showed a strong antiferromagnetic (AFM) to paramagnetic (PM) transition existed at 76 K, 77 K and 67 K for samples (x = 0, 0.25 and 0.50), respectively.

BSCCO 2212 Defective Tellurium Ions on Bi-Site

2011 ◽  
Vol 319-320 ◽  
pp. 161-166 ◽  
Author(s):  
Morsy M.A. Sekkina ◽  
M. El-Hofy ◽  
Khaled M. Elsabawy ◽  
M. Bediwy
Keyword(s):  
Electrical Conductivity ◽  
Transition Temperature ◽  
Critical Transition ◽  
Chemical Formula ◽  
Hole Filling ◽  
Critical Transition Temperature ◽  
Solid State Reaction Technique ◽  
Conventional Solid State Reaction ◽  
Major Phase ◽  
Dc Electrical Conductivity

BSCCO 2212 superconducting samples, doped Tellurium, with the chemical formula Bi2-xTexSr2CaCu2O8, were prepared by the conventional solid state reaction technique. The prepared samples were studied utilizing XRD, DC-electrical conductivity and SEM. XRD spectra indicated that 2212 with tetragonal structure is the major phase, whereas Bi-2201 and CaTeO4 are minor phases. At higher Te-additions x, traces from some other semi conducting phases were detected. The critical transition temperature Tcoffset was found to decrease non-linearly with x, which attributed to the hole filling caused by the liberated electrons of Te4+ ions. For x–values in the range 0.1 ≤ x ≤ 0.4, the steepness of (ρ vs T) relationship increases abruptly around 150 K; this was attributed to change in the oxygen vacancy feature (phase-like transition). SEM photographs revealed that as Te-content increases the compactness of the surface and the connectivity of the grains decreases, while pores and voids increase as a result of decreasing the amount of Bi and presence of multiple-phases in the sample.

scholarly journals Gap Structure of the Overdoped Iron-Pnictide Superconductor Ba(Fe0.942Ni0.058)2As2: A Low-Temperature Specific-Heat Study

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Gang Mu ◽  
Bo Gao ◽  
Xiaoming Xie ◽  
Yoichi Tanabe ◽  
Jingtao Xu ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Low Temperature ◽  
Specific Heat ◽  
Energy Gap ◽  
Critical Transition ◽  
Critical Transition Temperature ◽  
Iron Pnictide ◽  
Iron Pnictide Superconductor ◽  
Low Temperature Specific Heat ◽  
Co Doped

Low-temperature specific heat (SH) is measured on the postannealed Ba(Fe1−xNix)2As2single crystal withx= 0.058 under different magnetic fields. The sample locates on the overdoped sides and the critical transition temperatureTcis determined to be 14.8 K by both the magnetization and SH measurements. A simple and reliable analysis shows that, besides the phonon and normal electronic contributions, a clearT2term emerges in the low temperature SH data. Our observation is similar to that observed in the Co-doped system in our previous work and is consistent with the theoretical prediction for a superconductor with line nodes in the energy gap.

Superconductivity in Y-Ba-Cu-Ag-O and Y-Ba-Cu-Pt-O Systems

1987 ◽  
Vol 99 ◽  
Author(s):  
V. T. Kovachev ◽  
M. M. Gospodinov ◽  
E. S. Vlachov ◽  
V. A. Lovchinov ◽  
P. K. Svestarov ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Transition Temperature ◽  
Solid State ◽  
Superconducting State ◽  
High Purity ◽  
Solid State Synthesis ◽  
Pure Oxygen ◽  
Ac Magnetic Susceptibility ◽  
Source Materials

A STUDY OF THE Y-Ba-Cu-Ag-O SYSTEM: The specimens studied were produced using the standard ceramic technique. High purity source materials Y2O3, BaCO3CuO, and Ag2O were used. Solid state synthesis was carried out at 900 C for six hours in oxygen ambient. Pressed samples of 16 mm diameter and 2 mm thick were processed in an atmosphere of pure oxygen at 950 C for 12 hours. The transition temperature to the superconducting state was measured by the four point probe resistance technique. The ac magnetic susceptibility was determined by the method outlined in [1].

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