Superconductivity above 50K in LnFeAsO1-y (Ln= Nd, Sm, Gd, Tb and Dy) Synthesized by High-pressure Technique

Abstract

We have succeeded in synthesizing single-phase polycrystalline samples of oxygen-deficient oxypnictide superconductors, LnFeAsO1-y (Ln: lanthanide elements) with Ln=La, Ce, Pr, Nd, Sm, Gd, Tb and Dy using high-pressure synthesis technique. It is found out that the synthesis pressure is the most important parameter for synthesizing single-phase samples, in particular for the heavier Ln?s, such as Tb and Dy. The lattice parameters systematically decrease with the atomic number of Ln, reflecting the shrinkage of Ln ionic radius. For the lighter Ln?s (La, Ce, Pr, Nd), Tc increases monotonously with decreasing the lattice parameters from 26K for Ln=La to 54K for Ln=Nd, then stays at the constant value around 53K for the heavier counterpart (Nd, Sm, Gd, Tb and Dy). The results suggest the intimate relationship between the crystal structural parameters and the superconductivity on the one hand, as well as the possible existence of the inherent maximum Tc on the other, which is located around 50 K in the LnFeAsO based materials.

14 pages, 10 figures,Accepted for publication in Journal of the Physical Society of Japan Vol.78No.3

References in corpus (11)

• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
• Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO${}_{1-x}$F${}_x$FeAs
• Structural and magnetic phase diagram of CeFeAsO1-xFx and its relationship to high-temperature superconductivity
• Superconductivity and Phase Diagram in the Iron-based Arsenic-oxides ReFeAsO1-delta (Re = rare earth metal) without F-Doping
• Superconductivity in iron-based F-doped layered quaternary compound Nd[O1-xFx]FeAs
• Thorium-doping induced superconductivity up to 56 K in Gd1-xThxFeAsO
• Effect of Structural Parameters on Superconductivity in Fluorine-Free LnFeAsO1-y (Ln=La,Nd)
• Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering
• Bandwidth and Fermi surface of Iron-Oxypnictides: covalency and sensitivity to structural changes
• Superconductivity at 53.5 K in GdFeAsO1-delta
• High pressure synthesis of late rare earth RFeAs(O,F) superconductors; R = Tb and Dy

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• RE L${}_3$ X-ray absorption study of REO${}_{1-x}$F${}_x$FeAs (RE=La, Pr, Nd, Sm) oxypnictides
• Heavily Hydride-ion-doped 1111-type Iron-based Superconductors: Synthesis, Physical Properties and Electronic Structure