We have studied the magnetism in superconducting single crystals of EuFe2 As1.4 P0.6 by using the local probe techniques of zero-field muon spin rotation/relaxation and 151 Eu/57 Fe M\"ossbauer spec- troscopy. All of these measurements reveal magnetic hyperfine fields below the magnetic ordering temperature TM = 18 K of the Eu2+ moments. The analysis of the data shows that there is a coexistence of ferromagnetism, resulting from Eu2+ moments ordered along the crystallographic c-axis, and superconductivity below TSC \approx 15 K. We find indications for a change in the dynamics of the small Fe magnetic moments (\sim 0.07 \mu B) at the onset of superconductivity: below TSC the Fe magnetic moments seem to be "frozen" within the ab-plane.
@article{arxiv.1105.1201,
title = {Magnetism in superconducting EuFe$_2$As$_{1.4}$P$_{0.6}$ single crystals studied by local probes},
author = {J. Munevar and H. Micklitz and M. Alzamora and C. Arguello and T. Goko and F. L. Ning and A. A. Aczel and T. Munsie and T. J. Williams and G. F. Chen and W. Yu and G. M. Luke and Y. J. Uemura and E. Baggio-Saitovitch},
journal= {arXiv preprint arXiv:1105.1201},
year = {2014}
}