Muon spin rotation study of magnetism and superconductivity in BaFe2−xCoxAs₂ and Pr1−xSrxFeAsO

Bernhard, Christian; Drew, Alan J.; Schulz, Leander; Malik, Vivek Kumar; Rössle, Matthias; Niedermayer, Ch.; Wolf, Th.; Varma, G. D.; Mu, G.; Wen, H.-H.; Liu, H.; Wu, G.; Chen, X. H.

doi:10.1088/1367-2630/11/5/055050

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Journal article

Muon spin rotation study of magnetism and superconductivity in BaFe₂₋_xCo_xAs₂ and Pr₁₋_xSr_xFeAsO

Bernhard, Christian Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Switzerland -
Drew, Alan J. Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Switzerland - Queen Mary University of London, UK
Schulz, Leander Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Switzerland
Malik, Vivek Kumar Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Switzerland
Rössle, Matthias Department of Physics and Fribourg Center for Nanomaterials - Frimat, University of Fribourg, Switzerland
Niedermayer, Ch. Laboratory for Neutron Scattering, ETHZ & PSI, Switzerland
Wolf, Th. Forschungszentrum Karlsruhe, Germany
Varma, G. D. Department of Physics, Indian Institute of Technology Roorkee, India
Mu, G. National Laboratory for Superconductivity, Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Science, China
Wen, H.-H. National Laboratory for Superconductivity, Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Science, China
Liu, H. University of Science and Technology of China, Hefei, Anhui, China
Wu, G. University of Science and Technology of China, Hefei, Anhui, China -
Chen, X. H. University of Science and Technology of China, Hefei, Anhui, China

19.05.2009

Published in:

New Journal of Physics. - 2009, vol. 11, p. 055050

Superconductivity

English We present a muon spin rotation (μSR) study of the magnetic and superconducting properties of single crystals of electron-doped BaFe_2−xCo_xAs₂ with x = 0.08, 0.20 and 0.25 (T_c = 9, 25 and 20 K) and of polycrystalline hole-doped Pr_1−xSr_xFeAsO with x = 0 and 0.2 (T_c = 15 K). In the former series, we observe some interesting parallels with the electron-doped SmFeAsO_1−xF_x 1111-type system (Drew et al 2009 Nat. Mater. 8 310). In particular, we obtain evidence that strongly disordered static magnetism coexists with superconductivity on a microscopic scale in underdoped samples and even at optimum doping there is a slowing down (or enhancement) of dynamic magnetic correlations below T_c≈25 K. In contrast, for the hole-doped Pr₁₋_xSr_xFeAsO samples we obtain evidence for a mesoscopic phase segregation into regions with nearly unperturbed antiferromagnetic (AF) order and others that are non-magnetic and most likely superconducting. The observed trend resembles the one that was previously reported for hole-doped Ba₁₋_xK_xFe₂As₂ (Aczel et al 2008 Phys. Rev. B 78 214503, Park et al 2009 Phys. Rev. Lett. 102 117006) and thus might be a common property of the hole-doped systems.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

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