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arXiv · 1501.04005

Slow magnetic fluctuations and superconductivity in fluorine-doped NdFeAsO

G. Lamura·T. Shiroka·P. Bonfà·S. Sanna·R. De Renzi·M. Putti·N. D. Zhigadlo·S. Katrych·R. Khasanov·J. Karpinski
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Abstract

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.

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G. Lamura, T. Shiroka, P. Bonfà, S. Sanna, R. De Renzi, M. Putti, N. D. Zhigadlo, S. Katrych, R. Khasanov, J. Karpinski. 2015-01-16. Slow magnetic fluctuations and superconductivity in fluorine-doped NdFeAsO. https://doi.org/10.1103/physrevb.91.024513

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