Document Type

Article

Publication Date

1-16-2014

Journal or Book Title

Physical Review B

Volume

89

First Page

014510

DOI

10.1103/PhysRevB.89.014510

Abstract

We present the evolution of the initial (up to ∼10 kbar) hydrostatic pressure dependencies of Tc and of the ambient pressure, and the jump in the heat capacity associated with the superconducting transition as a function of Na doping in the Ba1−xNaxFe2As2 family of iron-based superconductors. For Na concentrations 0.15≤x≤0.9, the jump in specific heat at Tc, ΔCp∣∣Tc, follows the ΔCp∝T3 (the so-called BNC scaling) found for most BaFe2As2-based superconductors. This finding suggests that, unlike the related Ba1−xKxFe2As2 series, there is no significant modification of the superconducting state (e.g., change in superconducting gap symmetry) in the Ba1−xNaxFe2As2series over the whole studied Na concentration range. Pressure dependencies are nonmonotonic for x=0.2 and 0.24. For other Na concentrations, Tc decreases under pressure in an almost linear fashion. The anomalous behavior of the x=0.2 and 0.24 samples under pressure is possibly due to the crossing of the phase boundaries of the narrow antiferromagnetic tetragonal phase, unique for the Ba1−xNaxFe2As2 series, with the application of pressure. The negative sign of the pressure derivatives of Tc across the whole superconducting dome (except for x=0.2) is a clear indication of the nonequivalence of substitution and pressure for the Ba1−xNaxFe2As2 series.

Comments

This article is from Physical Review B 89 (2014): 014510, doi:10.1103/PhysRevB.89.014510. Posted with permission.

Copyright Owner

American Physical Society

Language

en

File Format

application/pdf

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