MuSR studies of RE(O,F)FeAs (RE = La, Nd, Ce) and LaOFeP systems: possible incommensurate/stripe magnetism and superfluid density

TL;DR

This study uses MuSR measurements to explore magnetic order and superfluid density in various iron-based superconductors, revealing complex magnetic behaviors and a linear relationship between superfluid density and critical temperature similar to cuprates.

Contribution

It provides new insights into magnetic states and superfluid density scaling in RE(O,F)FeAs and LaOFeP systems, highlighting possible incommensurate magnetism and universal scaling laws.

Findings

Long-range commensurate order in undoped LaOFeAs

Possible incommensurate or stripe magnetism in F-doped LaOFeAs

Weak magnetism in superconducting LaOFeP, Ce, and Nd-based compounds

Abstract

Muon spin relaxation (MuSR) measurements in iron oxy-pnictide systems have revealed: (1) commensurate long-range order in undoped LaOFeAs; (2) Bessel function line shape in La(O0.97F0.03)FeAs which indicates possible incommensurate or stripe magnetism; (3) anomalous weak magnetism existing in superconducting LaOFeP, Ce(O0.84F0.16)FeAs, and Nd(O0.88F0.12)FeAs but absent in superconducting La(O0.92F0.08)FeAs; and (4) scaling of superfluid density and Tc in the Ce, La, and Nd-FeAs superconductors following a nearly linear relationship found in cuprates.