Superconductivity in CeO_{1-x}F_xFeAs with upper critical field of 94 T

TL;DR

This study reports the synthesis of CeO_{1-x}F_xFeAs superconductors with an exceptionally high upper critical field of 94 T, highlighting their potential for high-field applications and revealing insights into their electronic properties.

Contribution

It introduces a new fluorine-doped CeOFeAs superconductor with record high upper critical field and detailed analysis of its structural and electronic characteristics.

Findings

Achieved an upper critical field Hc2(0) of 94 T in CeO_{1-x}F_xFeAs.

Observed a decrease in transition temperature with increased fluorine doping.

Confirmed electron-dominated conduction and strong electron-electron correlations.

Abstract

We have successfully synthesized Ce based oxypnictide with fluorine doping (CeO_{1-x}F_xFeAs) by a two step solid state reaction method. Detailed XRD and EDX confirm the crystal structure and chemical compositions. We observe that an extremely high Hc2(0) of 94 T can be achieved in the x = 0.1 composition. This increase in Hc2(0) is accompanied by a decrease in transition temperature (38.4 K in x = 0.1 composition) from 42.5 K for the x = 0.2 phase. The in-plane Ginzburg-Landau coherence length is estimated to be ~ 27 A at x = 0.2 suggesting a moderate anisotropy in this class of superconductors. The Seebeck coefficient confirms the majority carrier to be electrons and strong dominance of electron-electron correlations in this multiband superconductor.