Nanoscopic coexistence of magnetic and superconducting states within the FeAs layers of CeFeAsO1-xFx

TL;DR

This study reveals that in CeFeAsO1-xFx, magnetic and superconducting states coexist at the nanoscopic level within the same layers, providing insights into their transition behavior without a quantum critical point.

Contribution

It demonstrates nanoscopic coexistence of magnetism and superconductivity in CeFeAsO1-xFx, clarifying the transition mechanism and challenging previous quantum critical point hypotheses.

Findings

Magnetic transition at 30 K and superconducting transition at 18 K.

Nanoscopic coexistence of phases below 10 K.

No evidence of a quantum critical point in the phase diagram.

Abstract

We report on the coexistence of magnetic and superconducting states in CeFeAsO1-xFx for x=0.06(2), characterized by transition temperatures T_m=30 K and T_c=18 K, respectively. Zero and transverse field muon-spin relaxation measurements show that below 10 K the two phases coexist within a nanoscopic scale over a large volume fraction. This result clarifies the nature of the magnetic-to-superconducting transition in the CeFeAsO1-xFx phase diagram, by ruling out the presence of a quantum critical point which was suggested by earlier studies.