Electric Properties of Barium Cuprate Synthesized by Secondary Induction Heating

Abstract

Barium cuprate has been synthesized using secondary inductive heating. It is found that the single-phase product is formed when the equimolar mixture of Ba(NO₃)₂ and CuO is kept in the inductive furnace for 40 min at 1173 К. Reflections in the diffraction patterns are indexed in cubic syngony (Im3m space group). Parameters of the unit cell are refined according to the Rietveld method: a = 1.82996(7) nm and V = 6.1281(7) nm³ (R_Bragg = 4.42% and R_f = 3.61%). Iodometric titration data show that a half of the copper atoms are in oxidized state in BaCuO_2.25. Partial oxidation of copper (Cu^2.5+) influences the electrical properties of the synthesized cuprate, examined using impedance spectroscopy within the range 453 ≤ Т ≤ ≤ 593 K. The electrical conductivity of BaCuO_2.25, which is non-stoichiometric towards oxygen, exhibits semiconducting nature with activation energy of E_dc = 0.29 eV.