Novel Y_2-xPr_xRu₂O₇ (x=0-2) pyrochlore oxides prepared using a soft chemistry route and their electrical properties

Y_2-xPr_xRu₂O₇ (0≤x≤2) pyrochlore powders were prepared using a precipitation method, which allowed control of their composition and morphology. Materials structure and morphology were characterized by X-ray diffraction analysis and field emission scanning electron microscopy, respectively. All the synthesized powders exhibited a single pyrochlore phase with particle size depending on the Pr content. Powders with Pr content smaller than 25 mol% were nanometric. X-ray photoelectron spectroscopy analysis revealed a mixed oxidation state of both Pr and Ru, and a variation of the oxidation state of the elements in response to oxygen partial pressure changes. Electrical conductivity measurements were performed by dc 4-probe method at several temperatures, showing that increasing the Pr content in the A site of the pyrochlore structure increased the oxide electrical conductivity.