Pressure dependence of the superconductor transition temperature of Ca(Fe1−xCox)AsF compounds: A comparison with the effect of pressure on LaFeAsO1−xFx

Hironari Okada; Hiroyuki Takahashi; Satoru Matsuishi; Masahiro Hirano; Hideo Hosono; Kazuyuki Matsubayashi; Yoshiya Uwatoko; Hiroki Takahashi

doi:10.1103/PhysRevB.81.054507

Pressure dependence of the superconductor transition temperature of Ca(Fe1−xCox)AsF compounds: A comparison with the effect of pressure on LaFeAsO1−xFx

Hironari Okada, Hiroyuki Takahashi, Satoru Matsuishi, Masahiro Hirano, Hideo Hosono, Kazuyuki Matsubayashi, Yoshiya Uwatoko, Hiroki Takahashi

DOI 10.1103/PhysRevB.81.054507 · Physical Review B

T1

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Abstract

We performed systematic investigation of pressure effect on superconductivity in Ca(Fe1−xCox)AsF. Pressure-induced superconductivity was observed for x=0.0 after suppression of the antiferromagnetically ordered orthorhombic phase at the critical pressure Pc∼5 GPa. Unlike the pressure effect on Tc in F-doped LaFeAsO, all the Co-doped superconductors show no marked enhancement, which is less than 1 K. Consequently, the highest Tc among Ca(Fe1−xCox)AsF was obtained in parent compound. These results suggest that Co doping suppresses superconductivity. The maximum Tc observed in parent compound is higher than that in LaFeAsO, suggesting that CaFeAsF is considered as a candidate parent compound for realizing higher Tc.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
CaFeAsF Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	29	5 GPa	onset
Ca(Fe0.9Co0.1)AsF Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	23.8	Pressure unresolved	onset
Ca(Fe0.9Co0.1)AsF Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	24.7	1 GPa	onset
Ca(Fe0.8Co0.2)AsF Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	16.4	Pressure unresolved	onset
Ca(Fe0.8Co0.2)AsF Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	16.7	0.4 GPa	onset
Ca(Fe0.85Co0.15)AsF Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	20.4	Pressure unresolved	onset
Ca(Fe0.85Co0.15)AsF Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	20.7	0.4 GPa	onset
LaFeAsO Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	21	12 GPa	onset
FeSe Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	8	Pressure unresolved	onset
FeSe Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	37	7 GPa	onset
LaFeAsO0.86F0.14 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	19	Pressure unresolved	onset
LaFeAsO0.86F0.14 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	43	Pressure not reported	onset