Paraconductivity of K-doped SrFe2As2 superconductor

TL;DR

This study investigates the paraconductivity of K-doped SrFe2As2 superconductors, demonstrating that fluctuation conductivity near Tc aligns with three-dimensional theories and scaling laws, with results consistent with experimental data.

Contribution

The paper provides the first detailed analysis of fluctuation conductivity in K-doped SrFe2As2, confirming 3D fluctuation models and scaling behavior under magnetic fields.

Findings

Fluctuation conductivity fits 3D Lawrence-Doniach model near Tc.

Paraconductivity obeys Ullah-Dorsey scaling law under magnetic field.

Estimated critical field and coherence length match experimental data.

Abstract

Paraconductivity of the optimally K-doped SrFe2As2 superconductor is investigated within existing fluctuation mechanisms. The in-plane excess conductivity has been measured in high quality single crystals, with a sharp superconducting transition at Tc=35.5K and a transition width less than 0.3K. The data have been also acquired in external magnetic field up to 14T. We show that the fluctuation conductivity data in zero field and for temperatures close to Tc, can be explained within a three-dimensional Lawrence-Doniach theory, with a negligible Maki-Thompson contribution. In the presence of the magnetic field, it is shown that paraconductivity obeys the three-dimensional Ullah-Dorsey scaling law, above 2T and for H||c. The estimated upper critical field and the coherence length nicely agree with the available experimental data.