Measurements of the fluctuation-induced in-plane magnetoconductivity at high reduced temperatures and magnetic fields in the iron arsenide BaFe(2-x)NixAs2

TL;DR

This study investigates superconducting fluctuations in BaFe(2-x)NixAs2 crystals across various doping levels using magnetoconductivity measurements, testing Ginzburg-Landau models at high temperatures and fields.

Contribution

It provides the first comprehensive analysis of fluctuation-induced magnetoconductivity in iron-based superconductors at high reduced temperatures and magnetic fields, validating theoretical models.

Findings

Ginzburg-Landau approach applicability confirmed at high T and H

Doping dependence of coherence lengths characterized

Anisotropy factor varies with doping level

Abstract

The superconducting fluctuations well inside the normal state of Fe-based superconductors were studied through measurements of the in-plane paraconductivity and magnetoconductivity in high quality BaFe(2-x)NixAs2 crystals with doping levels from the optimal (x=0.10) up to the highly overdoped (x=0.20). These measurements, performed in magnetic fields up to 9 T perpendicular to the ab (Fe) layers, allowed a reliable check of the applicability to iron-based superconductors of Ginzburg-Landau approaches for 3D anisotropic compounds, even at high reduced temperatures and magnetic fields. Our results also allowed us to gain valuable insights into the dependence on the doping level of some central superconducting parameters (coherence lengths and anisotropy factor).