Interrelation Between Structural and Electrical Properties in RuSr2GdCu2O 8±Z Prepared Under Different Annealing Conditions

The effect of annealing in flowing oxygen on the structural and electrical properties of the rutheno-cuprate RuSr 2 GdCu 2 O 8±z (Ru-1212) was investigated. The solid-state reaction method was used to synthesize the Ru-1212 compound at ambient pressure using temperatures between 960 and 1000 °C in air. Pure-phase samples were obtained and then annealed in flowing oxygen at 1060 °C for 0, 48, 72, or 168 hrs. The structural data of each sample were refined by the Rietveld method. Cell parameters, a and c, as well as the Cu-O(1) interatomic distances increase as the annealing time in flowing oxygen increases. The temperature-dependent electrical resistance of the sample that was not annealed in flowing oxygen shows semiconducting behavior. In contrast, samples annealed in flowing oxygen show superconducting transitions. All these results indicate that the structural and electrical properties of the Ru-1212 compound are related.