WDX-Analysis of the New Superconductors RO(1-x)F(x)FeAs and Its Consequences on the Electronic Phase Diagram

Abstract

Polycrystalline samples of RO1-xFxFeAs (0 < x < 0.25) (R = La, Sm, Gd) were investigated by wavelength-dispersive X-ray spectroscopy (WDX) in the electron microscope to determine the composition of the samples, in particular the fluorine content. It was found that the measured fluorine content can deviate considerably from the initial weight. In the lanthanum compound LaO1-xFxFeAs, we found good agreement mainly for x > 0.05, but for x < 0.05 the fluorine hardly goes into the sample. For the samarium compound we measured less than half the fluorine in the sample as initially weighed at all fluorine concentrations. These measured values are taken into account when drawing the electronic phase diagrams of LaO1-xFxFeAs and SmO1-xFxFeAs. This leads to a more consistent picture of both of the diagrams in comparison to the plot of the initial weight.

5 pages, 4 figures, Accepted for publication in Journal of Superconductivity and Novel Magnetism

References in corpus (4)

• Structural and magnetic phase diagram of CeFeAsO1-xFx and its relationship to high-temperature superconductivity
• Coexistence of static magnetism and superconductivity in SmFeAsO1-xFx as revealed by muon spin rotation
• High-Field Pauli-Limiting Behavior and Strongly Enhanced Upper Critical Magnetic Fields near the Transition Temperature of an Arsenic-Deficient LaO_0.9F_0.1FeAs_(1-δ) Superconductor
• Feshbach resonances and mesoscopic phase separation near a quantum critical point in multiband FeAs-based superconductors

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• High pressure growth and electron transport properties of superconducting SmFeAsO1-xHx single crystals
• High $J_{\mathrm{c}}$ and low anisotropy of hydrogen doped NdFeAsO superconducting thin film
• Status of Iron Based Superconductors: characteristics and relevant properties for applications