We have studied the structural and electronic phase diagrams of CeFeAsO1-xFx and SmFeAsO1-xFx by a detailed analysis of muon spin relaxation experiments, synchrotron X-ray diffraction, Mossbauer spectroscopy, electrical resistivity, specific heat, an
d magnetic susceptibility measurements (Full abstract in the main document).
We study the interplay of magnetic and superconducting order in single crystalline hole doped Ba1-xNaxFe2As2 using muon spin relaxation. We find microscopic coexistence of magnetic order and superconductivity. In a strongly underdoped specimen the tw
o forms of order coexist without any measurable reduction of the ordered magnetic moment by superconductivity, while in a nearly optimally doped sample the ordered magnetic moment is strongly suppressed below the superconducting transition temperature. This coupling can be well described within the framework of an effective two-band model incorporating inter- and intra-band interactions. In optimally doped Ba1-xNaxFe2As2 we observe no traces of static or dynamic magnetism and the temperature dependence of the superfluid density is consistent with two s-wave gaps without nodes.
