Effect of Ru substitution in tellurium bridged copper spin 12 system Ba2CuTeO6: Structure, magnetism and optical properties

Abstract In this paper we have explored and analyzed the crystal structure, magnetic and optical properties of Ru doped double perovskite compound Ba2CuTe1-xRuxO6 (x = 0, 0.05 and 0.1). Detailed analysis of powder x-ray diffraction data at room temperature confirms the formation of single phase with monoclinic crystal structure (space group C2/m). A careful deconvolution of Ru and Cu x-ray photoelectron spectra indicates the formation of mixed oxidation states: Ru (4+ and 5+) and Cu (2+ and 3+). Electron paramagnetic resonance (EPR) spectra also support the presence of EPR silent Cu3+ (S = 0) ions. A broad overturn around 66 K in temperature dependent magnetization data of pure compound gets gradually suppressed in Ru doped samples. Magnetic frustration decreases with increase of Ru doping concentration due to different magnetic competitive interactions. Optical properties (change of color) are influenced due to the formation of 4d (Ru) energy levels in the vicinity of Fermi level.