59Co and 75As NMR Investigation of Electron-Doped High Tc Superconductor BaFe1.8Co0.2As2 (Tc = 22 K)

Journal Article · Wed Oct 15 04:00:00 EDT 2008 · Journal of the Physical Society of Japan

DOI:https://doi.org/10.1143/JPSJ.77.103705· OSTI ID:965847

Ning, F. L. ^[1]; Ahilan, K. ^[1]; Imai, T. ^[1]; Safa-Sefat, Athena ^[2]; Jin, Rongying ^[2]; McGuire, Michael A ^[2]; Sales, Brian C ^[2]; Mandrus, David ^[2]

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1. McMaster University
2. ORNL

We report an NMR investigation of the superconductivity in BaFe2As2 induced by Co doping(Tc = 22 K). We demonstrate that Co atoms form an alloy with Fe atoms and donate carriers without creating localized moments. Our finding strongly suggests that the underlying physics of iron-pnictide superconductors is quite different from the widely accepted physical picture of high Tc cuprates as doped Mott insulators. We also show a crossover of electronic properties into a low temperature pseudo-gap phase with a pseudo-gap of ~560 K. The NMR Knight shift below Tc decreases for both along the c-axis and ab-plane, and is consistent with the singlet pairing scenario.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 965847
• Journal Information: Journal of the Physical Society of Japan, Journal Name: Journal of the Physical Society of Japan Vol. 77; ISSN JUPSAU; ISSN 0031-9015
• Country of Publication: United States
• Language: English