Electronic transport properties of superconducting FeSe thin films in a magnetic field

11th European Conference on Applied Superconductivity

Zaitsev, A.G.^1 ; Schneider, R.^1 ; Fuchs, D.^1 ; Beck, A.^1 ; Hott, R.^1

Karlsruhe Institute of Technology, Institute for Solid-State Physics, Karlsruhe

D-76021, Germany^1

关键词: Electronic transport properties;    Film resistivity;    Interpolation schemes;    Logarithmic dependence;    Lower temperatures;    Thermally activated;    Upper critical fields;    Werthamer-Helfand-Hohenberg;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/507/1/012054/pdf
DOI  :  10.1088/1742-6596/507/1/012054

来源: IOP

【 摘 要 】

Superconducting c-axis oriented tetragonal FeSe films were grown on (001) MgO substrates. The transition temperature increased with film thickness and reached 10.5 K for a 2 μm film. The upper critical field, Bc2, was measured up to 14 T and then extrapolated to lower temperatures by an interpolation scheme based on Werthamer-Helfand-Hohenberg theory. The highest Bc2(0) was obtained for the 2 μm film: 28.8 T and 24.7 T in parallel and normal field, respectively. The effect of thermally activated flux-flow on the film resistivity was analysed, and the activation energies (U0) were extracted. At temperatures not far below Tcand fields above 1 T we observed a clear logarithmic dependence of U0(B), which is an evidence for the 2D vortex matter. At lower fields and temperatures the vortex matter behaved 3D-like.