Influence of the Fe Concentration on the Superconducting Properties of Fe1-Y Se

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

San Carlos de Bariloche

Conferencia; Advanced Topics in Magnetism and Superconductivity; 2014

We present a comparative study of electrical transport properties in the normal state and in the dissipative superconducting state between pure eta-FeSe phase and Fe deficient Fe1-ySe crystals. We discuss the influence of the intergrowth of magnetic hexagonal phase (Fe7Se8) in Fe deficient samples when compared to pure eta-FeSe samples. In the superconducting state, we measured the ab-plane electrical resistivity with magnetic field up to 16 T and the electrical resistivity as a function of the angle between the c axis and the applied field. The angular dependence at fixed temperature below the superconducting critical temperature, Tc(H =0), is very different for both sets of crystals. The Fe deficient samples display a vortex pinning related feature at ~57o off the plane while the pure eta-FeSe phase samples show the persistence of a strong angular dependent magnetoresistance characteristic of the normal state electronic structure.