Publisher’s Note: Specific heat and upper critical fields in KFe2As2single crystals [Phys. Rev. B85, 134533 (2012)]

2012 ◽  
Vol 85 (17) ◽  
Author(s):  
M. Abdel-Hafiez ◽  
S. Aswartham ◽  
S. Wurmehl ◽  
V. Grinenko ◽  
C. Hess ◽  
...  
Keyword(s):  
Specific Heat ◽  
Critical Fields ◽  
Upper Critical Fields

scholarly journals Specific heat and upper critical fields in KFe2As2single crystals

2012 ◽  
Vol 85 (13) ◽  
Author(s):  
M. Abdel-Hafiez ◽  
S. Aswartham ◽  
S. Wurmehl ◽  
V. Grinenko ◽  
C. Hess ◽  
...  
Keyword(s):  
Specific Heat ◽  
Critical Fields ◽  
Upper Critical Fields

Physical Properties of Li2Pd3B and Li2Pt3B Superconductors

2007 ◽  
Vol 561-565 ◽  
pp. 2079-2082 ◽  
Author(s):  
Hiroyuki Takeya ◽  
Shigeru Kasahara ◽  
Mohammed El Massalami ◽  
Takashi Mochiku ◽  
Kazuto Hirata ◽  
...  
Keyword(s):  
Specific Heat ◽  
Relaxation Method ◽  
Zero Magnetic Field ◽  
Bcs Theory ◽  
Superconducting Gap ◽  
Electronic Specific Heat ◽  
Superconducting Transition ◽  
Critical Fields ◽  
Resistivity Measurements ◽  
Upper Critical Fields

Superconductivity in two Li-containing compounds of Li2Pd3B and Li2Pt3B was recently discovered. These materials, showing the superconducting transition at 7.2 K and 2.6 K, respectively, have the same cubic structure (P4332) composed of distorted octahedrons without mirror or inversion symmetry along any directions. This is a very interesting feature of those materials in relation to the symmetry of superconductivity. Resistivity measurements in magnetic fields gave their upper critical fields, Hc2(0) = 45 kOe and 19 kOe, respectively. Their specific heat was measured using a heat-pulse relaxation method. The Sommerfeld coefficient (γ) and Debye temperature (θD) terms of Li2Pd3B were given as γ=9.5 mJmol-1K-2 and θD=228 K . The value of C/γT at Tc was calculated to be 1.7. In the same manner, those parameters were described for Li2Pt3B as γ=9.6 mJmol-1K-2, θD=240 K, and C/γTc =0.75, respectively. Since C/γTC in the weakcoupling limit by the BCS theory is 1.43, the value of 1.7 for Li2Pd3B is slightly higher. The electronic specific heat of Li2Pd3B at a zero magnetic field follows the typical exponetial behavior discribed in the BCS theory, while that of Li2Pt3B shows quadratic behavior. This result suggests the line nodes exist in the superconducting gap of Li2Pt3B driven by the spin-orbit interaction.

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
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