NMR Characterization of Sulphur Substitution Effects in the KxFe2−ySe2−zSz High-Tc Superconductor
We present a {sup 77}Se NMR study of the effect of S substitution in the high-T{sub c} superconductor K{sub x}Fe{sub 2-y}Se{sub 2-z}S{sub z} in a temperature range up to 250 K. We examine two S concentrations, with z = 0.8 (T{sub c} {approx} 26 K) and z = 1.6 (nonsuperconducting). The samples containing sulphur exhibit broader NMR line shapes than the K{sub x}Fe{sub 2}Se{sub 2} sample due to local disorder in the Se environment. Our Knight shift {sup 77}K data indicate that in all samples, uniform spin susceptibility decreases with temperature, and that the magnitude of the Knight shift itself decreases with increased S concentration. In addition, S substitution progressively suppresses low-frequency spin fluctuations. None of the samples exhibit an enhancement of low-frequency antiferromagnetic spin fluctuations near T{sub c} in 1/T{sub 1}T, as seen in FeSe.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE SC OFFICE OF SCIENCE (SC)
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1049250
- Report Number(s):
- BNL-98200-2012-JA; R&D Project: PO-013; KC0202010; TRN: US1204429
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 85, Issue 14; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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NMR characterization of sulphur substitution effects in the KxFe2-ySe2-xSz high-Tc superconductor
NMR characterization of sulphur substitution effects in the KxFe2-ySe2-zSz high-Tc superconductor