Synthesis and physical characterization of superconductivity–magnetism crossover compound RuSr2EuCeCu2O10−δ

Abstract We carefully studied the nonsuperconducting sample of the magneto-superconducting RuSr 2 (Eu 1− x Ce x )Cu 2 O 10− δ series with composition RuSr 2 EuCeCu 2 O 10− δ . This compound seems to exhibit a complex magnetic state as revealed by host of techniques like resistivity, thermopower, magnetic susceptibility, and MR measurements. The studied compound exhibited ferromagnetic like M ( H ) loops at 5, 20, and 50 K, and semiconductor like electrical conduction down to 5 K, with − MR 7 T of up to 4% at low temperatures. The − MR 7 T decreases fast above 150 K and monotonically becomes close to zero above say 230 K. Below, 150 K − MR 7 T decreases to around 3% monotonically down to 75 K, with further increase to 4% at around 30 K and lastly having a slight decrease below this temperature. The thermopower S ( T ) behavior closely followed the − MR 7 T steps in terms of d( S / T )/d T slopes. Further, both MR 7 T steps and d( S / T )/d T slopes are found in close vicinity to various magnetic ordering temperatures ( T mag ) of this compound.