scholarly journals Heat capacity jump atTcand pressure derivatives of superconducting transition temperature in the Ba1−xKxFe2As2(0.2≤x≤1.0) series

2013 ◽  
Vol 87 (10) ◽  
Author(s):  
Sergey L. Bud'ko ◽  
Mihai Sturza ◽  
Duck Young Chung ◽  
Mercouri G. Kanatzidis ◽  
Paul C. Canfield
Keyword(s):  
Heat Capacity ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Superconducting Transition ◽  
Heat Capacity Jump ◽  
Derivatives Of

scholarly journals Superconductivity in K- and Na-doped BaFe2As2: What can we learn from heat capacity and pressure dependence of Tc

2015 ◽  
Vol 29 (02) ◽  
pp. 1430019 ◽  
Author(s):  
Sergey L. Bud'ko
Keyword(s):  
Heat Capacity ◽  
Transition Temperature ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Pressure Dependence ◽  
Superconducting Transition ◽  
Phase Boundaries ◽  
Iron Based Superconductors ◽  
Heat Capacity Jump ◽  
Iron Based

A brief overview of changes in the superconducting transition temperature under pressure and evolution of specific heat capacity jump at Tc for two related families of iron-based superconductors, Ba 1-x K x Fe 2 As 2 (0.2 ≤ x ≤ 1.0) and Ba 1-x Na x Fe 2 As 2 (0.2 ≤ x ≤ 0.9) will be given. For Ba 1-x K x Fe 2 As 2 the specific heat capacity jump at Tc measured over the whole extent of the superconducting dome shows clear deviation from the empirical, [Formula: see text], scaling (known as the BNC scaling) for x > 0.7. At the same concentrations range apparent equivalence of effects of pressure and K -substitution on Tc fails. These observations suggests a significant change of the superconducting state for x > 0.7. In contrast, the data for the large portion of Ba 1-x Na x Fe 2 As 2 (0.2 ≤ x ≤ 0.9) series follow the BNC scaling. However, the pressure dependence of Tc (measured up to ~12 kbar) have clear nonlinearities for Na concentration in 0.2–0.25 region, that may be consistent with Tc crossing the phase boundaries of the emergent, narrow, antiferromagnetic/tetragonal phase. Results will be discussed in context other studies of these two related families of iron-based superconductors.

scholarly journals Enhancing Superconductivity of the Nonmagnetic Quasiskutterudites by Atomic Disorder

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5830
Author(s):  
Andrzej Ślebarski ◽  
Maciej M. Maśka
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
High Temperature Superconductors ◽  
Superconducting Phase ◽  
Length Scale ◽  
Superconducting Transition ◽  
Atomic Disorder ◽  
Strong Inhomogeneity ◽  
Related Compounds

We investigated the effect of enhancement of superconducting transition temperature Tc by nonmagnetic atom disorder in the series of filled skutterudite-related compounds (La3M4Sn13, Ca3Rh4Sn13, Y5Rh6Sn18, Lu5Rh6Sn18; M= Co, Ru, Rh), where the atomic disorder is generated by various defects or doping. We have shown that the disorder on the coherence length scale ξ in these nonmagnetic quasiskutterudite superconductors additionally generates a non-homogeneous, high-temperature superconducting phase with Tc⋆>Tc (dilute disorder scenario), while the strong fluctuations of stoichiometry due to increasing doping can rapidly increase the superconducting transition temperature of the sample even to the value of Tc⋆∼2Tc (dense disorder leading to strong inhomogeneity). This phenomenon seems to be characteristic of high-temperature superconductors and superconducting heavy fermions, and recently have received renewed attention. We experimentally documented the stronger lattice stiffening of the inhomogeneous superconducting phase Tc⋆ in respect to the bulk Tc one and proposed a model that explains the Tc⋆>Tc behavior in the series of nonmagnetic skutterudite-related compounds.

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