Structural analysis of polycrystalline CaRuO3 and SrRuO3 ceramics from room temperature up to 1273 K

We have studied the structure of SrRuO3 and CaRuO3 over temperature ranging from room to high temperature. Their structures were refined by X-ray Rietveld method. SrRuO3 and CaRuO3 are orthorhombically-distorted perovskites that have the GdFeO3-structure and the space group Pnma at room temperature. The structural temperature dependence of CaRuO3 indicates that the crystal became less distorted but this distortion persists up to 1273K. However, SrRuO3 presents a phase transition around 700K from Pnma (low temperatures) to Pm3m (high temperatures).