Intrinsic ferromagnetic impurity phases in SmFeAsO1-xFx detected by muSR

TL;DR

This study uses muSR measurements to identify ferromagnetic impurity phases in SmFeAsO1-xFx, revealing their influence on magnetic relaxation and clarifying intrinsic properties of iron pnictides.

Contribution

First detection and characterization of ferromagnetic impurity phases in SmFeAsO1-xFx using muSR, highlighting their impact on magnetic measurements.

Findings

Ferromagnetic impurities have a Curie temperature near room temperature.

Impurities cause significant magnetic relaxation in muSR measurements.

Impurities are common in iron pnictides and affect intrinsic property assessments.

Abstract

We report about muSR measurements on SmFeAsO1-xFx which helped us to identify the signature of diluted ferromagnetic inclusions, ubiquitous in the iron pnictides. These impurities are characterized by a Curie temperature close to room temperature and they seem responsible for a non negligible magnetic relaxation of the implanted muons, that should not be confused with intrinsic pnictide properties.