A Self-Doped Oxygen-Free High-Critical-Temperature (High- Tc) Superconductor: SmFFeAs

Inorg Chem. 2019 Nov 18;58(22):15401-15409. doi: 10.1021/acs.inorgchem.9b02464. Epub 2019 Nov 1.


A new iron-base superconductor SmFFeAs is synthesized via solid-state metathesis reaction by using SmFCl and LiFeAs as precursors. The compound crystallized in the tetragonal ZrCuSiAs-type structure with the space group P4/nmm and lattice parameters of a = 3.9399(0) Å and c = 8.5034(1) Å. The superconducting diamagnetic transition occurs at 56 K for the parent compound, which confirmed by the resistivity and magnetic susceptibility. The appearance of superconductivity without extrinsic doping could be ascribed to the self-doping owing to the mixed valence of Sm ions. The as-synthesized SmFFeAs serves as a new self-doped parent compound for oxygen-free high-critical-temperature (high-Tc) superconductors.