scholarly journals Resistive upper critical fields and irreversibility lines of optimally doped high-Tccuprates

1999 ◽  
Vol 60 (17) ◽  
pp. 12475-12479 ◽  
Author(s):  
Yoichi Ando ◽  
G. S. Boebinger ◽  
A. Passner ◽  
L. F. Schneemeyer ◽  
T. Kimura ◽  
...  
Keyword(s):  
Critical Fields ◽  
Upper Critical Fields ◽  
Irreversibility Lines

A novel technique for synthesizing MgB2thin films with high upper critical fields

2008 ◽  
Vol 21 (8) ◽  
pp. 085009 ◽  
Author(s):  
Y Shen ◽  
R Gandikota ◽  
R K Singh ◽  
F L Hunte ◽  
J Jaroszynski ◽  
...  
Keyword(s):  
Critical Fields ◽  
Novel Technique ◽  
Upper Critical Fields

Anisotropic Upper Critical Fields of Highly Oriented Bi-Sr-Ca-Cu-O Thin Films Prepared by Coevaporation

1988 ◽  
Vol 27 (Part 2, No. 6) ◽  
pp. L1094-L1096 ◽  
Author(s):  
Tsutomu Yoshitake ◽  
Tetsuro Satoh ◽  
Yoshimi Kubo ◽  
Takashi Manako ◽  
Hitoshi Igarashi
Keyword(s):  
Thin Films ◽  
Critical Fields ◽  
Upper Critical Fields

Structure and Functional Properties of Bulk MgB2 Superconductors Synthesized and Sintered under Pressure

2014 ◽  
Vol 792 ◽  
pp. 21-26 ◽  
Author(s):  
Tatiana Prikhna ◽  
Michael Eisterer ◽  
Wolfgang Gawalek ◽  
Athanasios G. Mamalis ◽  
Artem Kozyrev ◽  
...  
Keyword(s):  
Critical Current ◽  
Material Structure ◽  
Bulk Materials ◽  
Critical Fields ◽  
Current Densities ◽  
Upper Critical Fields ◽  
Irreversibility Fields ◽  
Grain Boundary Pinning ◽  
Effect Of Oxygen ◽  
Oxygen Impurities

The high pressure (50 MPa - 2 GPa) – high temperature synthesized MgB2 bulk materials are characterized by nearly theoretical density (1-2% porosity), 80-98% connectivity, extremely high critical current densities (e.g. at 20 K, in 0–1 T jc=1.3–1.0 MA·cm-2 (with 10% SiC) and jc= 0.92 – 0.73 MA·cm-2 (without doping)), large irreversibility fields (Birr(18.4 K) =15 T and Birr (0 K) = 32.5 T) and high upper critical fields (Bc2 (22 K) =15 T and Bc2(0 K) ~ 42.1 T). The transformation of grain boundary pinning to point pinning in MgB2-based materials with increasing manufacturing temperature (from 800 to 1050 oC) under pressures from 0.1 to 2 GPa correlates well with an increase in critical current density in low external magnetic fields caused by the redistribution of boron and the oxygen impurities in the material structure. As the manufacturing temperature increases, the discontinuous oxygen enriched layers transform into distinct Mg-B-O inclusions and the size and amount of inclusions of higher magnesium borides MgBX (X>4) are reduced. The effect of oxygen and boron redistribution can be enhanced by Ti or SiC additions.

Upper critical fields of single-crystalline and polycrystalline Ca-Sr-Bi-Cu-O compounds

1988 ◽  
Vol 47 (2) ◽  
pp. 209-211 ◽  
Author(s):  
J. N. Li ◽  
K. Kadowaki ◽  
M. J. V. Menken ◽  
Y. K. Huang ◽  
K. Bakker ◽  
...  
Keyword(s):  
Critical Fields ◽  
Single Crystalline ◽  
Upper Critical Fields

scholarly journals Extent of Fermi-surface reconstruction in the high-temperature superconductor HgBa2CuO4+δ

2020 ◽  
Vol 117 (18) ◽  
pp. 9782-9786
Author(s):  
Mun K. Chan ◽  
Ross D. McDonald ◽  
B. J. Ramshaw ◽  
Jon B. Betts ◽  
Arkady Shekhter ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Surface Reconstruction ◽  
Field Measurements ◽  
Temperature Dependent ◽  
Crucial Issue ◽  
Critical Fields ◽  
Sign Change ◽  
Underdoped Cuprates ◽  
Upper Critical Fields ◽  
Fermi Surface Reconstruction

High magnetic fields have revealed a surprisingly small Fermi surface in underdoped cuprates, possibly resulting from Fermi-surface reconstruction due to an order parameter that breaks translational symmetry of the crystal lattice. A crucial issue concerns the doping extent of such a state and its relationship to the principal pseudogap and superconducting phases. We employ pulsed magnetic-field measurements on the cuprate HgBa2CuO4+δ to identify signatures of Fermi-surface reconstruction from a sign change of the Hall effect and a peak in the temperature-dependent planar resistivity. We trace the termination of Fermi-surface reconstruction to two hole concentrations where the superconducting upper critical fields are found to be enhanced. One of these points is associated with the pseudogap endpoint near optimal doping. These results connect the Fermi-surface reconstruction to both superconductivity and the pseudogap phenomena.

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