Anisotropic Phase Diagram and Superconducting Fluctuations in SmFeAsO0.85F0.15

TL;DR

This study investigates the anisotropic phase diagram and superconducting fluctuations in optimally doped SmFeAsO0.85F0.15, revealing insights into its critical behavior, anisotropy, and electronic density of states.

Contribution

It provides the first detailed specific heat analysis of the anisotropic phase diagram and superconducting fluctuations in SmFeAsO0.85F0.15 single crystals.

Findings

Superconducting transition at 49.5 K with a specific heat anomaly of 24 mJ/molK^2.

Superconducting fluctuations cause broadening and suppression of the specific heat anomaly in magnetic fields.

Anisotropy ratio of approximately 8 and an upper critical field slope of -3.5 T/K.

Abstract

We report on the specific heat determination of the anisotropic phase diagram of single crystals of optimally doped SmFeAsO1-xFx. In zero-field, the optimally doped compound displays a clear cusp-like anomaly in C/T with {\Delta}C/Tc = 24 mJ/molK2 at Tc = 49.5 K. In magnetic fields applied along the c-axis, we find pronounced superconducting fluctuations induced broadening and suppression of the specific heat anomaly which can be described using three-dimensional lowest-Landau-level scaling with an upper critical field slope of -3.5 T/K and an anisotropy of {\Gamma} = 8. The small value of {\Delta}C/Tc yields a Sommerfeld coefficient {\gamma} ~ 8 mJ/molK2 indicating that SmFeAsO1-xFx is characterized by a modest density of states and strong coupling.