Publication Type
Journal
Journal Name
Journal of the Physical Society of Japan
Publication Date
Page Numbers
47 to 53
Volume
77
Abstract
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.
