Transport, thermal, and magnetic properties of RuSr2(Gd1.5Ce0.5)Cu2O10-δ, a magnetic superconductor.

Resistivity, thermoelectric power, heat capacity, and magnetization for samples of RuSr₂(Gd_1.5Ce_0.5)Cu₂O_10-δ were investigated in the temperature range 1.8–300 K with a magnetic field up to 8 T. The resistive transitions to the superconducting state are found to be determined by the inhomogeneous (granular) structure, characterized by the intragranular, T_c0, and intergranular, T_cg, transition temperatures. Heat capacity, C(T), shows a jump at the superconducting transition temperature T_c0≈37.5 K. A Schottky-type anomaly is found in C(T) below 20 K. This low-temperature anomaly can be attributed to splitting of the ground term ⁸S_7/2 of paramagnetic Gd³⁺ ions by internal and external magnetic fields. [ABSTRACT FROM AUTHOR]