Among the widely studied superconducting iron-pnictide compounds belonging to the Ln1111 family (with Ln a lanthanide), a systematic investigation of the crossover region between the superconducting and the antiferromagnetic phase for the Ln = Nd case has been missing. We fill this gap by focusing on the intermediate doping regime of NdFeAsO(1-x)F(x) by means of dc-magnetometry and muon-spin spectroscopy measurements. The long-range order we detect at low fluorine doping is replaced by short-range magnetic interactions at x = 0.08, where also superconductivity appears. In this case, longitudinal-field muon-spin spectroscopy experiments show clear evidence of slow magnetic fluctuations that disappear at low temperatures. This fluctuating component is ascribed to the glassy-like character of the magnetically ordered phase of NdFeAsO at intermediate fluorine doping.
@article{arxiv.1501.04005,
title = {Slow magnetic fluctuations and superconductivity in fluorine-doped NdFeAsO},
author = {G. Lamura and T. Shiroka and P. Bonfà and S. Sanna and R. De Renzi and M. Putti and N. D. Zhigadlo and S. Katrych and R. Khasanov and J. Karpinski},
journal= {arXiv preprint arXiv:1501.04005},
year = {2015}
}