Intrinsic Ferromagnetic Impurity Phases in SmFeAsO1-xFx Detected bymuSR

We report ?SR measurements on SmFeAsO1 - x F x which helped us to identify the signature of diluted ferro- magnetic 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 neg- ligible magnetic relaxation of the implanted muons, which should not be confused with intrinsic pnictide properties.