Magnetic and Transport Studies on Electron-doped CeFeAsO1-xFx Superconductor

TL;DR

This study investigates the magnetic and transport properties of electron-doped CeFeAsO1-xFx superconductors, revealing high upper critical fields, low anisotropy, and the effects of fluorine doping on Tc and magnetic behavior.

Contribution

The paper provides new insights into the magnetic and transport characteristics of CeFeAsO1-xFx superconductors, highlighting their high upper critical fields and doping-dependent Tc saturation.

Findings

Superconducting transition temperature (Tc) reaches 40 K with increased fluorine doping.

High upper critical field estimated at over 48 Tesla.

Low anisotropy indicated by minimal Tc broadening under magnetic fields.

Abstract

The magnetic and transport behaviors of cerium substituted iron oxy-arsenide superconductor with x = 0.1 to 0.4 fluoride (F) doping have been investigated in this report. Temperature dependent susceptibility and resistivity measurements showed the 0.1 F-doped sample (CeFeAsO0.9F0.1) has a superconducting transition temperature (Tc) of around 30 K. With increasing doping beyond x = 0.2 Tc saturates to around 40 K. Temperature dependent susceptibility measured in different magnetic fields for the under-doped sample showed Meissner effect in low field and the diamagnetism is still visible up to 1 Tesla, with an obvious magnetic transition below 5 K, perhaps originating from magnetic ordering of the rare earth cerium. The corresponding field dependent resistance versus temperature measurements indicated a broadening of less than 3 K for Tc at mid-point by increasing the field to 5 Tesla indicating rather low anisotropy. An estimated upper critical field of more than 48 Tesla and accordingly an estimated maximum coherence length of 2.6 nm were obtained confirming the high upper critical field with a short coherence length for this superconductor.