Multiband character of -FeSe: Angular dependence of the magnetoresistance and upper critical field

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

Buenos Aires

Conferencia; 27th International Conference on Low Temperature Physics (LT27); 2014

We studied ab-plane transport properties in single crystals of the superconductor \beta-FeSe up to 16 T. In the normal state, below 90 K, the crystals present a strongly anisotropic positive magnetoresistance that becomes negligible above that temperature. In the superconducting state (Tc=8.87(5) K) the upper critical field anisotropy Hc2kab/ Hc2kc changes with temperature and the angular dependence of the dissipation for fixed temperatures and fields reflects a strongly anisotropic behavior. Our results make evident that multiband effects are needed to describe the measured transport properties. We model the magnetoresistance and upper critical field behavior with a two-band model showing that the diffusivities ratioparameter remains unchanged going from the normal to the superconducting state.