Synthesis of the Ru-1232 compound in the RuSr2(Nd1−xDyxCe1.8Sr0.2)Cu2Oz system

We have synthesized the Ru-1232 compounds of RuSr2(Nd1−xDyxCe1.8Sr0.2)Cu2Oz. Nearly-single phase samples are found to exist in the x range from 0.2 to 0.5. All samples are semiconductors. Among them, the sample with x = 0.4 has the smallest resistivity. Though the sample is annealed under high-pressure O2 atmosphere at 143 atm, it does not exhibit any anomaly resulting from superconductivity of the Ru-1232 phase down to 4.2 K. From the result of the resistivity measurements, the transport process is expected for the sample to be followed by a three-dimensional variable range hopping conduction.