NMR characterization of sulphur substitution effects in the KxFe2-ySe2-zSz high-T-c superconductor

Article

关键词: HIGH-TEMPERATURE SUPERCONDUCTIVITY;    IRON;   

DOI  :  10.1103/PhysRevB.85.144516

来源: SCIE

【 摘 要 】

We present a Se-77 NMR study of the effect of S substitution in the high-T-c superconductor KxFe2-ySe2-zSz in a temperature range up to 250 K. We examine two S concentrations, with z = 0.8 (T-c similar to 26 K) and z = 1.6 (nonsuperconducting). The samples containing sulphur exhibit broader NMR line shapes than the KxFe2Se2 sample due to local disorder in the Se environment. Our Knight shift K-77 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-c in 1/T1T, as seen in FeSe.

【 授权许可】

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