Upward Curvature of the Upper Critical Field and the V-Shaped Pressure Dependence of T c in the Noncentrosymmetric Superconductor PbTaSe2

Based on two-band isotropic Ginzburg–Landau theory, we study the temperature dependence of upper critical field and London penetration depth for non-centrosymmetric superconductor LaNiC2. All the theoretical calculations fit the experimental data very well, especially the upward curvature of upper critical field near the critical temperature. Our results thus indicate that the two-gap scenario is better to account for the superconductivity of LaNiC2, and the Cooper pairs of this superconductor are in the conventional s-wave state.

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Anisotropic Upper Critical Field of Single Crystal RNi2B2C (R = Y, Lu)

International Journal of Modern Physics B ◽

10.1142/s021797929800243x ◽

1998 ◽

Vol 12 (29n31) ◽

pp. 3264-3266 ◽

Cited By ~ 13

Author(s):

A. C. Du Mar ◽

K. D. D. Rathnayaka ◽

D. G. Naugle ◽

P. C. Canfield

Keyword(s):

Low Temperature ◽

Single Crystal ◽

Critical Field ◽

Upper Critical Field ◽

Critical Fields ◽

Linear Behavior ◽

Upward Curvature

Measurements of the anisotropic upper critical field curves have been extended for YNi 2B2C and LuNi2B2C (T c = 15.6 K and 16.1 K, respectively). Measurements of R(T, H) were taken along the crystallographic directions of <100> and <110>. The resulting critical fields show an upward curvature near T c and a linear behavior at low temperature, which continues to below 2 K with little, if any, sign of saturation.

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Josephson-Coupling Origin for the Upward Curvature of the Pseudo-Upper-Critical Field inBi2Sr2−xLaxCuO6+δCrystals

Physical Review Letters ◽

10.1103/physrevlett.82.410 ◽

1999 ◽

Vol 82 (2) ◽

pp. 410-413 ◽

Cited By ~ 49

Author(s):

H. H. Wen ◽

W. L. Yang ◽

Z. X. Zhao ◽

Y. M. Ni

Keyword(s):

Critical Field ◽

Upper Critical Field ◽

Josephson Coupling ◽

Upward Curvature

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Upper Critical Field in Electron-Doped Superconductor with Nonstoichiometric Disorder near Antiferromagnetic-Superconducting Phase Boundary

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.215.77 ◽

2014 ◽

Vol 215 ◽

pp. 77-82 ◽

Cited By ~ 5

Author(s):

Tatiana B. Charikova ◽

Nina G. Shelushinina ◽

German I. Harus ◽

Denis S. Petukhov ◽

Andrei A. Ivanov

Keyword(s):

Phase Boundary ◽

Critical Field ◽

Upper Critical Field ◽

Superconducting Phase ◽

Spin Fluctuations ◽

S Wave ◽

Optimal Doping ◽

Resistivity Method ◽

Upward Curvature ◽

Disorder Parameter

Using the resistivity method it was found that temperature dependence of the upper critical field for underdoped Nd1.86Ce0.14CuO4+δ have an anomalous upward curvature of Hc2(T) dependence and can be consistently explained by the two-band/two-gap model of a dirty superconductor. Near antiferromagnetic-superconducting phase boundary the critical temperature remains constant with the change of the disorder parameter and the slope of Bc2 increases with increasing of the disorder parameter. This behavior is completely different from dependencies for pure superconducting phase at optimal doping region. This difference may indicate the change of the type of the paring: from the predominance of the anisotropic s-wave component (may be due to unstable competition between antiferromagnetic (AF) and superconducting (SC) regions) in underdoped (x=0.14) region to the prevalence of d-wave part in optimal doped regions (x=0.15) because of residual spin fluctuations.

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Evolution of Superconducting and Hidden Order Phases in URu2Si2 Under Applied Pressure

MRS Proceedings ◽

10.1557/proc-1104-nn09-02 ◽

2008 ◽

Vol 1104 ◽

Author(s):

M. Brian Maple ◽

Jason R. Jeffries ◽

Nicholas P. Butch ◽

Benjamin T. Yukich

Keyword(s):

Critical Field ◽

Pressure Dependence ◽

Ambient Pressure ◽

Applied Pressure ◽

Upper Critical Field ◽

Qualitative Change ◽

Resistivity Measurements ◽

Surface Fraction ◽

Hidden Order ◽

Two Phases

AbstractElectrical resistivity measurements performed under applied hydrostatic pressure and in magnetic fields have been used to probe the hidden order (HO) and superconducting (SC) states of URu2Si2, which have ambient-pressure transition temperatures TO = 17.5 K and Tc = 1.5 K, respectively. TO increases with applied pressure and a distinct kink in its pressure dependence is observed at 15 kbar; this feature is associated with the onset of antiferromagnetism. The pressure dependence of the SC upper critical field has been measured with the external field aligned parallel to both crystalline axes. The SC phase is smoothly suppressed to a critical pressure of about 15 kbar and no qualitative change in the critical field curves is observed. The co-evolution of the HO and SC phases is discussed within the context of a model in which the two phases compete for Fermi surface fraction.

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RESISTIVE UPPER CRITICAL FIELD OF SUPERCONDUCTING SPIN-LADDER Sr14-xCaxCu24O41

International Journal of Modern Physics B ◽

10.1142/s0217979200004131 ◽

2000 ◽

Vol 14 (29n31) ◽

pp. 3617-3622 ◽

Cited By ~ 6

Author(s):

T. NAKANISHI ◽

N. MOTOYAMA ◽

H. MITAMURA ◽

N. TAKESHITA ◽

H. TAKAHASHI ◽

...

Keyword(s):

High Pressure ◽

Critical Field ◽

Pressure Range ◽

Upper Critical Field ◽

Anomalous Behavior ◽

Spin Ladder ◽

Two Dimensional ◽

High Pressure Cell ◽

Upward Curvature ◽

Superconducting Oxides

We report the resistive upper critical field Hc2(T) of the hole-doped two-leg ladder Sr 14-x Ca x Cu 24 O 41(x=12) single crystal, which becomes superconducting with Tc~5 K in a pressure range above ~3.0 GPa . Using a newly developed compact high-pressure cell, the magneto-transport measurements have been performed at temperatures down to ~140 mK under high pressure above 3.5 GPa. It is found that Hc2 (perpendicular to the ladder Cu 2 O 3 plane) increases anomalously as the temperature is decreased having an upward curvature and shows no saturation down to T/T c ~ 0.03. Also, its temperature dependence is found to resemble that of the high-Tc superconducting oxide Tl 2 Ba 2 CuO 6. This fact suggests that the anomalous behavior of Hc2 has a common origin between the ladders and the two-dimensional high-Tc superconducting oxides.

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