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Title: High field nuclear magnetic resonance in transition metal substituted BaFe{sub 2}As{sub 2}

We report high field {sup 75}As nuclear magnetic resonance (NMR) measurements on Co and Cu substituted BaFe{sub 2}As{sub 2} single crystals displaying same structural/magnetic transition T{sub 0}≃128  K. From our anisotropy studies in the paramagnetic state, we strikingly found virtually identical quadrupolar splitting and consequently the quadrupole frequency ν{sub Q}≃2.57(1)  MHz for both compounds, despite the claim that each Cu delivers 2 extra 3d electrons in BaFe{sub 2}As{sub 2} compared to Co substitution. These results allow us to conclude that a subtle change in the crystallographic structure, particularly in the Fe–As tetrahedra, must be the most probable tuning parameter to determine T{sub 0} in this class of superconductors rather than electronic doping. Furthermore, our NMR data around T{sub 0} suggest coexistence of tetragonal/paramagnetic and orthorhombic/antiferromagnetic phases between the structural and the spin density wave magnetic phase transitions, similarly to what was reported for K-doped BaFe{sub 2}As{sub 2} [Urbano et al., Phys. Rev. Lett. 105, 107001 (2010)].
Authors:
; ; ; ; ;  [1] ; ;  [2]
  1. Instituto de Física “Gleb Wataghin,” UNICAMP, Campinas, SP 13083-859 (Brazil)
  2. National High Magnetic Field Laboratory, FSU, Tallahassee, Florida 32306-4005 (United States)
Publication Date:
OSTI Identifier:
22273842
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 17; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; ANTIFERROMAGNETISM; ARSENIC 75; BARIUM COMPOUNDS; COMPARATIVE EVALUATIONS; DOPED MATERIALS; ELECTRONS; IRON ARSENIDES; MONOCRYSTALS; NMR SPECTRA; NUCLEAR MAGNETIC RESONANCE; ORTHORHOMBIC LATTICES; PARAMAGNETISM; PHASE TRANSFORMATIONS; SUPERCONDUCTORS