Magnetic fluctuations under pressure on S-doped FeSe studied via 77Se NMR

FeSe1-xSx has attracted much attention among iron-based superconductors because the pure sample undergoes nematic and superconducting (SC) phase transitions without magnetism. A pressure-induced antiferromagnetic (AFM) phase emerges upon applying pressure. In the pressure (P)-temperature (T) phase diagram for the 12%-S doped sample, the AFM phase is separated from the nematic phase at around 3.0 GPa, and SC transition temperature (T-c) takes a maximum (similar to 30 K). We measured T-1 of Se-77 for the 12%-S doped FeSe at 3.0 GPa. We found from 1/T1T that low-energy AFM fluctuations are not so much enhanced under pressure compared with those at ambient pressure. The result suggests changes of topology and nesting of Fermi surfaces during pressurizing process. (c) 2018 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).