Superconducting and tetragonal-to-orthorhombic transitions in single crystals of FeSe1−xTex (0≤ x ≤0.61)

Abstract

Single crystals of FeSe1−xTex were grown for 0≤x≤0.41 by a flux method and at x=0.61 by chemical vapor transport in order to study the Te substitution effects on the quality of the single crystals and on their superconducting characteristics. From the in-plane resistivity data of the grown crystals, we found that the superconducting transition temperature Tc slightly decreases with increasing the doping level of x up to around x=0.2–0.3, then begins to increase with x at around x=0.4, and reaches a maximum around x=0.6. These experimental facts are contrasted with the results of thin films where Tc increases up to 23 K around x=0.2. We also observed an anomaly in the temperature dependence of the in-plane resistivity due to the tetragonal-to-orthorhombic structural transition Ts, which decreases nearly linearly with increasing x until finally disappearing near x=0.5. These features were not reported in previous studies performed with polycrystalline and thin film samples.

Source-reported materials — not catalogue approval

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