Investigation of Fe/Mo Ordering and Magnetic Properties of Ca₂Fe_xMo_2−xO₆ (x = 0.9, 1.0, 1.1 and 1.2) Double Perovskites Prepared by Sonochemical Method

Characterization, Fe/Mo ordering and magnetic properties of Ca₂Fe_xMo_2−xO₆ (x = 0.9, 1.0, 1.1 and 1.2) (CFMO) double perovskite have been studied. Sonochemical methodology is adopted to synthesize Ca₂Fe_xMo_2−xO₆ double perovskite at low temperature (950 ^∘ C) under Ar/H₂ atmosphere. Single-phase monoclinic structure by space group P2₁/n, lattice parameters (a, b and c) and unit cell volume (V ) have been confirmed from X-ray diffraction (XRD) patterns. Average grain sizes of 145 nm with a variation of porosity were observed from scanning electron microscopy (SEM) pictures. Elemental analysis using energy-dispersive X-ray spectroscopy (EDS) confirmed the presence of elements Ca, Fe, Mo and O with no trace of foreign elements, and the compound is found to be pure. Fourier transform infrared spectroscopy (FTIR) data confirmed perovskite formation by identifying three characteristic absorption bands in the wave number range 400–1000 cm^− 1 for Mo-O and Fe-O vibrations. Magnetic properties like M_s, M_r and H_c were studied for CFMO series using vibrating sample magnetometer (VSM). Saturation magnetization is found to vary with Fe composition (x).