Superconductivity under pressure in RFeAsO1−xFx (R = La, Ce−Sm) by dc magnetization measurements

Kiyotaka Miyoshi; Eiko Kojima; Saki Ogawa; Yuta Shimojo; Jun Takeuchi

doi:10.1103/PhysRevB.87.235111

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Superconductivity under pressure in RFeAsO1−xFx (R = La, Ce−Sm) by dc magnetization measurements

Kiyotaka Miyoshi, Eiko Kojima, Saki Ogawa, Yuta Shimojo, Jun Takeuchi

DOI 10.1103/PhysRevB.87.235111 · Physical Review B

T1

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Abstract

Superconducting transition under pressure (P) has been investigated for optimum-doped RFeAsO1−xFx (R=La, Ce–Sm) by dc magnetization measurements. For R=La, Tc is found to be pressure independent up to P∼3.0 GPa and then shows a monotonic decrease with increasing pressure. The plateau width decreases for the system with smaller lattice constants and shrinks to almost zero for R=Sm. From the Tc(P) data, we construct the Tc evolution map on the height of the As atom from the Fe-plane hAs versus lattice-constant a or c plane. It is shown that the characteristic Tc variations under pressure for all compounds and the rapid decrease in Tc induced by changing the R element from Sm to La can be described by a common Tc (hAs, a or c) surface, suggesting that Tc is determined by hAs and lattice constant. It is also suggested that there exists an upper limit of the lattice constant aulm (or culm), above which dTc/da (or dTc/dc) changes the sign from positive to negative.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
LaFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	28	Pressure unresolved	onset
LaFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	18	7 GPa	onset
CeFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	38	Pressure unresolved	onset
CeFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	25	4.4 GPa	onset
PrFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	43	Pressure unresolved	onset
PrFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	25	7 GPa	onset
NdFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	48	0.39 GPa	onset
NdFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	26	7.7 GPa	onset
SmFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	53	Pressure unresolved	onset
SmFeAsO1-xFx Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	29	7.7 GPa	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
Ba1-xKxFe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	38	Pressure not reported	unknown
Li1-xFeAs Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	18	Pressure not reported	unknown
FeSe Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8	Pressure not reported	unknown
K0.8Fe2Se2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	32	Pressure not reported	unknown