Magnetotransport properties and Seebeck effect in the superconductor FeSe0.5Te0.5

We carried out measurements of the electrical resistivity, magnetoresistance, Hall resistivity and Seebeck effect in a highly oriented sample of the Fe-based FeSe0.5Te0.5 superconductor. Complementary structural and magnetic characterizations were also performed. Our sample do not show long-range magnetic order down to 4.2 K. Superconductivity occurs with critical temperature Tc ≊ 15 K. In the normal phase, the resistivity versus temperature behavior mimics that of a Kondo-lattice system. The magnetoresistance, Hall coefficient and Seebeck coefficient show sign reversals. These results are discussed with basis on the combined effects from two-band conduction and weak magnetic fluctuations. Effects from superconducting fluctuations are also observed near Tc.