Synthesis, structural and electrical characterizations of DySr5Ni2.4Cu0.6O12-δ

A new compound DySr5Ni2.4Cu0.6O12-δ has been prepared by sol gel method and annealed at 1473 K in 1 atm of Ar gas flow. The X-ray diffraction (XRD) is used for phase identification. The sample shows to adopt the K2NiF4-type structure based on tolerance factor calculation. XRD analysis using the Rietveld method was carried out and it was found that DySr5Ni2.4Cu0.6O12-δ (Dy0.33Sr1.67Ni0.8Cu0.2O4-δ') compound crystallizes in tetragonal symmetry with space group I4/mmm (Z=2). The lattice parameters are found to be at room temperature a=3.7696(5) A and c=12.3747(2) A. The final reliability indices were: RB=5.219% and χ2=3.47. Four probe electrical resistivity measurements were performed versus temperature in the range 294-579 K. A semiconducting behaviour over the whole range of temperature, with a conductivity maximum of 0.4 S cm-1 is observed at 510 K. - Graphical abstract: DySr5Ni2.4Cu0.6O12-δ exhibits a semi-conducting behaviour over the whole temperature range 294-579 K with a conductivity maximum of 0.4 S cm-1 at 510 K. Highlights: → We described our attempts to synthesize the pure compound DySr5Ni2.4Cu0.6O12-δ. → Product was characterized by XRD and electrical resistivity measurements. → Iodometric titration was used for the analysis of the oxygen nonstoichiometry. → Calculated tolerance factor was included in the tetragonal symmetry stability range. → Compound exhibits a semi-conducting behaviour over the whole temperature range 294-579 K.