Muon spin rotation study of magnetism and superconductivity in Ba(Fe<sub>1−x</sub>Co<sub>x</sub>)₂As₂ single crystals

Bernhard, Christian; Wang, Chen Nan; Nuccio, Laura; Schulz, Leander; Zaharko, O.; Larsen, J.; Aristizabal, C.; Willis, M.; Drew, Alan J.; Varma, G. D.; Wolf, T.; Niedermayer, Ch.

doi:10.1103/PhysRevB.86.184509

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Journal article

Muon spin rotation study of magnetism and superconductivity in Ba(Fe_1−xCo_x)₂As₂ single crystals

Bernhard, Christian University of Fribourg, Department of Physics and Fribourg Centre for Nanomaterials, Switzerland
Wang, Chen Nan University of Fribourg, Department of Physics and Fribourg Centre for Nanomaterials, Switzerland
Nuccio, Laura University of Fribourg, Department of Physics and Fribourg Centre for Nanomaterials, Switzerland - Queen Mary University of London, School of Physics and Astronomy, United Kingdom
Schulz, Leander University of Fribourg, Department of Physics and Fribourg Centre for Nanomaterials, Switzerland
Zaharko, O. Laboratory for Neutron Scattering, Paul Scherrer Institut, Villigen, Switzerland - Department of Physics, Technical University of Denmark, Lyngby, Denmark
Larsen, J. Laboratory for Neutron Scattering, Paul Scherrer Institut, Villigen, Switzerland - Department of Physics, Technical University of Denmark, Lyngby, Denmark
Aristizabal, C. Queen Mary University of London, School of Physics and Astronomy, United Kingdom
Willis, M. Queen Mary University of London, School of Physics and Astronomy, United Kingdom
Drew, Alan J. Queen Mary University of London, School of Physics and Astronomy, United Kingdom
Varma, G. D. Department of Physics, Indian Institute of Technology Roorkee, India
Wolf, T. Karlsruher Institut für Technologie, Institut für Festkörperphysik, Karlsruhe, Germany
Niedermayer, Ch. Laboratory for Neutron Scattering, Paul Scherrer Institut, Villigen, Switzerland

19.10.2012

Published in:

Physical Review B - Condensed Matter and Materials Physics. - 2012, vol. 86, no. 14, p. 144112

English Using muon spin rotation (μSR) we investigated the magnetic and superconducting properties of a series of Ba(Fe_1−xCo_x)₂As₂ single crystals with 0≤x≤0.15. Our study details how the antiferromagnetic order is suppressed upon Co substitution and how it coexists with superconductivity. In the nonsuperconducting samples at 0c approaches the maximum value. The magnetic order develops here only in parts of the sample volume and it seems to cooperate with superconductivity since its onset temperature coincides with T_c. Even in the strongly overdoped regime at x = 0.11, where the static magnetic order has disappeared, we find that the low-energy spin fluctuations are anomalously enhanced below T_c. These findings point toward a drastic change in the relationship between the magnetic and superconducting orders from a competitive one in the strongly underdoped regime to a constructive one in near-optimally and overdoped samples.

Faculty

Faculté des sciences et de médecine

Department

Département de Physique

Language