Transport, thermal, and magnetic properties of RuSr_2(Gd_(1.5)Ce_(0.5))Cu_2O_(10-δ), a magnetic superconductor

摘要

Resistivity, thermoelectric power, heat capacity, and magnetization for samples of RuSr_2(Gd_(1.5)Ce_(0.5))Cu_2O_(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 Gd~(3+) ions by internal and external magnetic fields.