An analysis of electrical transport and magnetic susceptibility properties of YBa2Cu3O7-[delta] and La2-xSrxCuO4 high Tc superconductors

1997 ◽  
Author(s):  
Tai-fung Yu
Keyword(s):  
Magnetic Susceptibility ◽  
Electrical Transport ◽  
High Tc Superconductors ◽  
High Tc

scholarly journals Potassium-Doped Para-Terphenyl: Structure, Electrical Transport Properties and Possible Signatures of a Superconducting Transition

2020 ◽  
Vol 5 (4) ◽  
pp. 78
Author(s):  
Nicola Pinto ◽  
Corrado Di Nicola ◽  
Angela Trapananti ◽  
Marco Minicucci ◽  
Andrea Di Cicco ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Electrical Transport ◽  
Low Temperatures ◽  
Chemical Method ◽  
Preliminary Evidence ◽  
Superconducting Gap ◽  
Superconducting Transition ◽  
Electrical Transport Properties ◽  
High Tc ◽  
Resistivity Measurements

Preliminary evidence for the occurrence of high-TC superconductivity in alkali-doped organic materials, such as potassium-doped p-terphenyl (KPT), were recently obtained by magnetic susceptibility measurements and by the opening of a large superconducting gap as measured by ARPES and STM techniques. In this work, KPT samples have been synthesized by a chemical method and characterized by low-temperature Raman scattering and resistivity measurements. Here, we report the occurrence of a resistivity drop of more than 4 orders of magnitude at low temperatures in KPT samples in the form of compressed powder. This fact was interpreted as a possible sign of a broad superconducting transition taking place below 90 K in granular KPT. The granular nature of the KPT system appears to be also related to the 20 K broadening of the resistivity drop around the critical temperature.

Structural and Magnetic Characteristics of (Eu1-xGax) Ba2Cu3O7-δ High-Tc Superconductors

1997 ◽  
Vol 11 (13) ◽  
pp. 593-597 ◽  
Author(s):  
Iuliu Pop ◽  
Radu Redac ◽  
Gheorghe Borodi ◽  
Virgil Ioncu
Keyword(s):  
Magnetic Susceptibility ◽  
Temperature Dependence ◽  
Concentration Dependence ◽  
Tetragonal Structure ◽  
Magnetic Characteristics ◽  
High Tc Superconductors ◽  
High Tc ◽  
Gallium Concentration ◽  
Paramagnetic Region ◽  
Diamagnetic Transition

The high-T c ( Eu 1-x Ga x) Ba 2 Cu 3 O 7-δ superconductors with x=0, 0.01, 0.02, 0.03, 0.06 and 0.09 were synthesized by a ceramic technique. The gallium concentration dependence of the lattice parameters was determined. A transition from orthorhombic toward tetragonal structure was relevated for the most gallium concentrated sample. The temperature dependence of the magnetic susceptibility pointed out the diamagnetic transition at 78 and 80 K. In the paramagnetic region the magnetic susceptibility exhibits anomal temperature dependence.

43Ca NMR Study of Bismuth-Based High-Tc Superconductors

1994 ◽  
Vol 49 (1-2) ◽  
pp. 373-378 ◽  
Author(s):  
A. Trokiner ◽  
L. Le Noc ◽  
A. Yakubovskii ◽  
K.N. Mykhalyov ◽  
S.V. Verkhovskii
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Electronic Properties ◽  
High Tc Superconductors ◽  
High Tc ◽  
Structural Assignment ◽  
Bismuth Compounds ◽  
Nmr Study

Abstract As a first step of a study of the electronic properties of CuO2 planes by probing calcium nuclei in the bismuth-based high-Tc materials we report here the structural assignment of Ca NMR lines measured in 43Ca-enriched samples of n = 2 ((Bi,Pb)2Sr2CaCu2O8+x) and n = 3 ((Bi,Pb)2Sr2-Ca2Cu3O10+x) bismuth compounds. Powdered samples were investigated as well as oriented pow­ ders, achieved by uniaxial alignment of the grains in a 7T magnetic field. For the main calcium site (Ca between two CuO2 planes), we could determine the quadrupolar as well as the shift tensors. The results indicate that, in the same way as yttrium nuclei in YBaCuO, calcium nuclei are sensitive to the magnetic susceptibility of the metallic CuO2 planes.

MAGNETIC PROPERTIES OF Yb1-xGaxBa2Cu3O7-δ HIGH TC SUPERCONDUCTORS

2008 ◽  
Vol 22 (21) ◽  
pp. 3677-3682
Author(s):  
IULIU POP ◽  
CARMEN SBÂRCIOG ◽  
OVIDIU POP
Keyword(s):  
Magnetic Susceptibility ◽  
Curie Constant ◽  
Thermal Variation ◽  
High Tc Superconductors ◽  
High Tc ◽  
Static Magnetic Susceptibility ◽  
X Ray ◽  
Paramagnetic Region ◽  
Valence States ◽  
Superconducting Compounds

The thermal variation of the static magnetic susceptibility, for the Yb 1-x Ga x Ba 2 Cu 3 O 7-δ, x = 0.00; 0.01; 0.02; 0.03; 0.06 oxidic high TC superconductors was investigated. In the paramagnetic region, the reciprocal magnetic susceptibility temperature dependence is nonlinear, obeying the hyperbolic Neel law, valid for the ferromagnetic collinear magnetic structure. The effective magnetic moment value determined from the Curie constant is a giant one, suggesting the existence of Cu 3+ and Yb 6+ valence states in high TC superconducting compounds. The structural X-ray investigation revealed a homogeneous orthorhombic crystalline structure in Yb 1-x Ga x Ba 2 Cu 3 O 7-δ superconducting compounds.

The many faces of STEM in materials science

1991 ◽  
Vol 49 ◽  
pp. 440-441
Author(s):  
John Silcox
Keyword(s):  
Materials Science ◽  
Auger Spectroscopy ◽  
Dark Field ◽  
High Tc Superconductors ◽  
High Tc ◽  
Acoustic Environment ◽  
Electromagnetic Vibration ◽  
The Many ◽  
Serial Mode

Determination of the microstructure and microchemistry of small features often provides the insight needed for the understanding of processes in real materials. In many cases, it is not adequate to use microscopy alone. Microdiffraction and microspectroscopic information such as EELS, X-ray microprobe analysis and Auger spectroscopy can all contribute vital parts of the picture. For a number of reasons, dedicated STEM offers considerable promise as a quantitative instrument. In this paper, we review progress towards effective quantitative use of STEM with illustrations drawn from studies of high Tc superconductors, compound semiconductors and metallization of H-terminated silicon.Intrinsically, STEM is a quantitative instrument. Images are acquired directly by detectors in serial mode which is particularly convenient for digital image acquisition, control and display. The VG HB501A at Cornell has been installed in a particularly stable electromagnetic, vibration and acoustic environment. Care has been paid to achieving UHV conditions (i.e., 10-10 Torr). Finally, it has been interfaced with a VAX 3200 work station by Kirkland. This permits, for example, the acquisition of bright field (or energy loss) images and dark field images simultaneously as quantitative arrays in perfect registration.

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