Anisotropic superconducting properties of aligned Sm${}_{0.95}$La${}_{0.05}$FeAsO${}_{0.85}$F${}_{0.15}$ microcrystalline powder

Abstract

The Sm${}_{0.95}$La${}_{0.05}$FeAsO${}_{0.85}$F${}_{0.15}$ compound is a quasi-2D layered superconductor with a superconducting transition temperature T${}_c$ = 52 K. Due to the Fe spin-orbital related anisotropic exchange coupling (antiferromagnetic or ferromagnetic fluctuation), the tetragonal microcrystalline powder can be aligned at room temperature using the field-rotation method where the tetragonal $ab$-plane is parallel to the aligned magnetic field B${}_a$ and $c$-axis along the rotation axis. Anisotropic superconducting properties with anisotropic diamagnetic ratio ${\chi }_c/{\chi }_{ab}\sim$ 2.4 + 0.6 was observed from low field susceptibility $\chi$(T) and magnetization M(B${}_a$). The anisotropic low-field phase diagram with the variation of lower critical field gives a zero-temperature penetration depth ${\lambda }_c$(0) = 280 nm and ${\lambda }_{ab}$(0) = 120 nm. The magnetic fluctuation used for powder alignment at 300 K may be related with the pairing mechanism of superconductivity at lower temperature.

4 pages, 6 figures

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Cited by in corpus (1)

• Angular Dependence of X-ray Absorption Spectrum for Field-aligned Fe-based Superconductors