MAGNETORESISTANCE IN SINGLE CRYSTALS OF SUPERCONDUCTING FESE

M. L. AMIGÓ; M. V. ALE CRIVILLERO; D. G. FRANCO; G. NIEVA

Buenos Aires

Conferencia; 27th International Conference on Low Temperature Physics; 2014

Universidad de Buenos Aires

Transport, structural and magnetic properties were studied in single crystals of the superconductor β-FeSe. We grew them by the flux method and obtained pure samples, free from spurious phases (Fe_7Se_8 , metallic Fe, etc). We observed a change in the slope of the resistivity at T=90K, where a structural transition from the tetragonal to the orthorhombic phase is reported [1]. For T<90K, the crystals present a strongly anisotropic magnetoresistance in the ab-plane: positive with the applied field parallel to the c-axis and negligible with the field parallel to the ab-plane.A magnetic characterization of the crystals in the normal state, with the field parallel and perpendicular to the c-axis, showed no evidence of a magnetic feature at the structural transition temperature.In the superconducting state (T c =8.5K), we measured the ab-plane dissipation in transport experiments, with fields up to 16T. We observed a sharp superconducting transition, with a width that slightly increases with field. The angular dependence of the dissipation for fixed temperatures and fields reflects a strongly anisotropic behavior, which could be due to critical field anisotropy.[1] S. Margadonna, et al. Chem. Commun. (2008) 43, 5607-5609.