High-Tc Nodeless s±-wave Superconductivity in (Y,La)FeAsO1−y with Tc=50 K:As75-NMR Study

H. Mukuda; S. Furukawa; H. Kinouchi; M. Yashima; Y. Kitaoka; P. M. Shirage; H. Eisaki; A. Iyo

doi:10.1103/PhysRevLett.109.157001

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High-Tc Nodeless s±-wave Superconductivity in (Y,La)FeAsO1−y with Tc=50 K:As75-NMR Study

H. Mukuda, S. Furukawa, H. Kinouchi, M. Yashima, Y. Kitaoka, P. M. Shirage, H. Eisaki, A. Iyo

DOI 10.1103/PhysRevLett.109.157001 · Physical Review Letters

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Abstract

We report on an As75-NMR study on the Fe-pnictide high-Tc superconductor Y0.95La0.05FeAsO1−y (Y0.95La0.051111) with Tc=50 K that includes no magnetic rare-earth elements. The measurement of the nuclear-spin lattice-relaxation rate (751/T1) has revealed that the nodeless bulk superconductivity takes place at Tc=50 K while antiferromagnetic spin fluctuations develop moderately in the normal state. These features are consistently described by the multiple fully gapped s±-wave model based on the Fermi-surface nesting. Incorporating the theory based on band calculations, we propose that the reason that Tc=50 K in Y0.95La0.051111 is larger than Tc=28 K in La1111 is that the Fermi-surface multiplicity is maximized, and hence the Fermi-surface nesting condition is better than that in La1111.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Y0.95La0.05FeAsO1-y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	50	Pressure not reported	onset
LaFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	26	Pressure not reported	unknown
LaFeAsO1-y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	28	Pressure not reported	unknown
Y0.2La0.8FeAsO1-y Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	34	Pressure not reported	unknown
Ba0.6K0.4Fe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	38	Pressure not reported	unknown
(Ca4Al2O6)Fe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	27	Pressure not reported	unknown