Quasi-2D behavior of 112-type iron-based superconductors

TL;DR

This study investigates the anisotropic and quasi-two-dimensional superconducting behavior of 112-type iron-based superconductors through fluctuation magnetoconductivity and magnetization measurements, revealing high anisotropy and layered characteristics.

Contribution

It provides the first detailed analysis of the anisotropic superconducting properties of 112-type IBS, demonstrating their quasi-2D behavior near optimal doping levels.

Findings

High anisotropy parameter ($$ up to 30) in 112-type IBS.

Evidence of quasi-two-dimensional superconducting behavior.

Layered structure influences superconducting properties.

Abstract

Fluctuation magnetoconductivity and magnetization above the superconducting transition temperature (Tc) are measured on the recently discovered 112 family of iron-based superconductors (IBS), Ca$_{1-x}$La$_x$Fe$_{1-y}$Ni$_y$As$_2$, which presents an extra As-As chain spacer-layer. The analysis in terms of a generalization of the Lawrence-Doniach (LD) approach to finite applied magnetic fields indicates that these compounds are among the most anisotropic IBS ($\gamma$ up to ~30), and provides a compelling evidence of a quasi-two-dimensional behavior for doping levels near the optimal one.