Cobalt-substitution-induced Superconductivity in a New Compound with ZrCuSiAs-type Structure, SrFeAsF

Abstract

We have synthesized a quaternary fluoroarsenide SrFeAsF with the ZrCuSiAs-type structure (P4/nmm, a = 0.3999 and c = 0.8973 nm), which is composed of an alternately stacked (FeAs)- and (SrF)+ layers, analogous to the FeAs-based superconductor LaFeAsO. SrFeAsF shows metallic type conduction with the anomaly at ~180 K. The partial replacement of the Fe with Co suppresses the anomaly and induces the superconductivity, while the maximal Tc (4 K for SrFe0.875Co0.125AsF) is much lower than that of the Co-substituted LaFeAsO. Replacement of (LaO)+ layers with (SrF)+ layers results in a enlargement of the c-axis length (+2.6%). These results suggest the importance of interlayer interaction as a critical Tc-controlling factor in FeAs-based superconductors.

J. Phys. Soc. Jpn. in-press

References in corpus (4)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO${}_{1-x}$F${}_x$FeAs
• Thorium-doping induced superconductivity up to 56 K in Gd1-xThxFeAsO
• Superconductivity at 52 K in iron-based F-doped layered quaternary compound Pr[O1-xFx]FeAs

Cited by in corpus (1)

• Band structure of tetragonal and orthorhombic fluorine-arsenide SrFeAsF as a parent phases for a new group of oxygen-free FeAs superconductors