Electrical and magnetic properties of RuGd1.6Ce0.4Sr2Cu2O10-δ

We have studied the electrical and magnetic properties of normal and superconducting states of RuGd1.6Ce0.4Sr2Cu2O10-δ (Ru-1222) system, prepared by the standard solid-state reaction technique, with applied magnetic field. The resistivity curves show that at high temperature the system is paramagnetic. At lower temperature, we can observe two magnetic transitions from paramagnetic state to anti-ferromagnetic and from anti-ferromagnetic to ferromagnetic. At room temperature the resistivity of sample shows insulating behavior and superconducting transition occurs at 45 K. Superconducting and magnetic parameters such as superconducting transition temperature Tc, magnetic transition Tirr, have been obtained through resistivity curve as a function of external magnetic field. We have observed that samples become superconductor at Tc which decrease from 49 K to 38 K with external magnetic field up to 1.6 T. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)