Abstract
We investigate the thermodynamic and transport properties of silver-substituted BaFe2As2 (122) crystals up to ∼4.5%. Similar to other transition-metal substitutions in 122, Ag diminishes the antiferromagnetic (TN) and structural (TS) transition temperatures, but unlike other electron-doped 122s, TN and TS coincide without splitting. Although magnetism drops precipitously to TN=84K at doping x=0.029, it only weakly changes above this x, settling at TN=80K at x=0.045. Compared to this persistent magnetism in Ag-122, doping other group 11 elements of either Cu or Au in 122 diminished TN and induced superconductivity near Tc=2K at x=0.044 or 0.031, respectively. Ag-122 crystals show reflective surfaces with surprising thicker cross sections for x≥0.019, the appearance that is in contrast to the typical thin stacked layered feature seen in all other flux-grown x122 and lower Ag-122. This physical trait may be a manifest of intrinsic weak changes in c lattice and TN. Our theoretical calculations suggest that Ag doping produces strong electronic scattering and yet a relatively small disruption of the magnetic state, both of which preclude superconductivity in this system.
Original language | English |
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Article number | 134510 |
Journal | Physical Review B |
Volume | 94 |
Issue number | 13 |
DOIs | |
State | Published - Oct 12 2016 |