scholarly journals Superconducting Properties of (Sm/Y)-Ba-Cu-0 High Tc Composite Superconductors with CeO2Additive by Zone-Melt Textured Growth

2002 ◽  
Vol 15 (3) ◽  
pp. 269-274
Keyword(s):  
Superconducting Properties ◽  
High Tc ◽  
Composite Superconductors ◽  
Zone Melt

APPLICATION OF ESR TO HIGH-Tc SUPERCONDUCTORS AND RELATED MATERIALS IV: ALKALI K DOPING EFFECTS ON THE SUPERCONDUCTING CHARACTERISTICS OF K3C60

1999 ◽  
Vol 13 (02) ◽  
pp. 59-69
Author(s):  
K. SUGAWARA ◽  
N. OHYA ◽  
N. ARAI ◽  
S. ICHIMURA ◽  
K. YAMAMOTO ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Calcination Temperature ◽  
Volume Fraction ◽  
Superconducting Properties ◽  
High Tc Superconductors ◽  
High Tc ◽  
Doping Effects ◽  
Superconducting Volume Fraction ◽  
Vortex Size ◽  
Quartz Tubes

Several samples of K 3 C 60 have been made by the calcination of C 60 powder plus K flakes in evacuated quartz tubes at temperatures between 100°C and 700°C for 24 hours. The non-resonant microwave absorption (NRMA) measurements have been done below T c for these samples. From the linewidths and intensities of the NRMA signals, the superconducting properties (T c superconducting volume fraction and vortex size) have been studied as a function of the calcination temperature.

scholarly journals Effect of Gallium Focused Ion Beam Irradiation on Properties of YBa2Cu3Ox/La0.67Sr0.33MnO3 Heterostructures

2011 ◽  
Vol 62 (2) ◽  
pp. 109-113 ◽  
Author(s):  
Vladimír Štrbík ◽  
Štefan Beňačka ◽  
Štefan Gaži ◽  
Vasilij Šmatko ◽  
Štefan Chromik ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Weak Link ◽  
Ion Beam ◽  
Superconducting Properties ◽  
Beam Irradiation ◽  
Ion Beam Irradiation ◽  
Film Properties ◽  
High Tc ◽  
Nanometer Size ◽  
Fib Patterning

Effect of Gallium Focused Ion Beam Irradiation on Properties of YBa2Cu3Ox/La0.67Sr0.33MnO3 Heterostructures We present initial investigation of the superconductor-ferromagnet-superconductor (SFS) heterostructures of nanometer dimensions prepared by the gallium focused ion beam (FIB) technology. The SFS heterostructures were realized on the basis of high-Tc superconducting YBa2Cu3Ox and ferromagnetic La0.67Sr0.33MnO3 thin films. SFS weak link junctions require dimensions of the weak link connection in the range of nanometer size realizable by FIB patterning. On the other side the gallium focused ion beam might bring about unacceptable degradation of the superconducting as well as ferromagnetic thin film properties. The presented results show that FIB offers a suitable procedure for realization of nanometer size devices but some degradation of the ferromagnetic and superconducting properties was observed. Solution of this problem will be achieved in the next stage of our investigations.

scholarly journals Orbital Symmetry and Orbital Excitations in High-Tc Superconductors

2019 ◽  
Vol 4 (2) ◽  
pp. 46 ◽  
Author(s):  
Andrzej M. Oleś ◽  
Krzysztof Wohlfeld ◽  
Giniyat Khaliullin
Keyword(s):  
Simplified Model ◽  
Entangled States ◽  
Cooper Pairing ◽  
Superconducting Properties ◽  
High Tc Superconductors ◽  
Orbital Symmetry ◽  
Spin Orbital ◽  
High Tc ◽  
High Energies

We discuss a few possibilities of high- T c superconductivity with more than one orbital symmetry contributing to the pairing. First, we show that the high energies of orbital excitations in various cuprates suggest a simplified model with a single orbital of x 2 − y 2 symmetry doped by holes. Next, several routes towards involving both e g orbital symmetries for doped holes are discussed: (i) some give superconductivity in a CuO 2 monolayer on Bi2212 superconductors, Sr 2 CuO 4 − δ , Ba 2 CuO 4 − δ , while (ii) others as nickelate heterostructures or Eu 2 − x Sr x NiO 4 , could in principle realize it as well. At low electron filling of Ru ions, spin-orbital entangled states of t 2 g symmetry contribute in Sr 2 RuO 4 . Finally, electrons with both t 2 g and e g orbital symmetries contribute to the superconducting properties and nematicity of Fe-based superconductors, pnictides or FeSe. Some of them provide examples of orbital-selective Cooper pairing.

Relation of starting precursors to the resulting high-Tc phases in the Pb and Sb doped Bi—Sr—Ca—Cu—O system

1994 ◽  
Vol 9 (2) ◽  
pp. 292-296 ◽  
Author(s):  
F. Constantinescu ◽  
R. Holiastou ◽  
D. Niarchos ◽  
G.K. Nicolaides ◽  
F. Vasiliu ◽  
...  
Keyword(s):  
Ac Susceptibility ◽  
Partial Substitution ◽  
Dc Resistivity ◽  
Squid Magnetometry ◽  
Superconducting Properties ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Phase Sample ◽  
Semiconducting Behavior

The introduction of more reactive precursors for Pb and Sr (oxalates), as well as Ca (citrate) and the use of a Bi nitrate decomposition route, has increased the percentage of the high-Tc (2223) phase in the Bi—Sr—Ca—Cu—O (BSCCO) system. Partial substitution of Bi(Pb) with Sb gives an almost single (2223) phase sample. In addition, a single (2212) phase sample is obtained when high purity Bi2O3 is used as a precursor, whereas Bi acetate leads to semiconducting behavior. The morphology of the samples is studied with a scanning electron microscope (SEM), the stoichiometry with energy-dispersive x-ray analysis (EDAX), and the structure with x-ray diffraction (XRD), while the superconducting properties are investigated by dc-resistivity, ac-susceptibility, and SQUID magnetometry techniques.

Structural and Superconducting Properties of RE1 - 2xPrxCaxSr0.8Ba1.2Cu3O7 - δ (RE = Er and Gd) High Tc Superconductors

2003 ◽  
Vol 17 (13) ◽  
pp. 2609-2622 ◽  
Author(s):  
N. Charoenthai ◽  
P. Winotai ◽  
R. Suryanarayanan ◽  
I. M. Tang
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Transition Temperature ◽  
Size Effect ◽  
High Temperature Superconductors ◽  
Superconducting Properties ◽  
High Tc Superconductors ◽  
High Tc ◽  
Oxygen Annealing ◽  
Ion Size

We report here on the structural and superconducting properties of RE 1 - 2x Pr x Ca x Sr 0.8 Ba 1.2 Cu 3 O 7 - δ (RE = Er and Gd, 0 ≤ x ≤ 0.2) high temperature superconductors. The transition temperature (Tc) of these compounds decreases when the Pr and Ca concentrations are increased. At constant Pr and Ca concentrations, the Tc of Er 1 - 2x Pr x Ca x Sr 0.8 Ba 1.2 Cu 3 O 7 - δ superconductor system is higher than that observed for the Gd 1 - 2x Pr x Ca x Sr 0.8 Ba 1.2 Cu 3 O 7 - δ system. For the Gd 0.8 Pr 0.1 Ca 0.1 Sr 0.8 Ba 1.2 Cu 3 O 7 - δ sample, after heating in argon followed by oxygen annealing, the orthorhombicity increases accompanied by 10 K increase in Tc. These results show that though our data indicate an ion-size effect, the Tc suppression rate dTc/dx depends very much on the heat treatment adopted to prepare the samples.

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