Preparation and characterization of Co2+ substituted Li–Dy ferrite ceramics

Abstract Stoichiometric compositions of ferrites with the chemical formula Li 0.5−0.5 x Co x Fe 2.4−0.5 x Dy 0.1 O 4 with x =0, 0.25, 0.5, 0.75, 1.0 were prepared by the standard double sintering ceramic method. X-ray diffraction analysis confirmed the cubic spinel structure of the prepared samples. The structural, morphological and magnetic properties were studied by X-ray diffraction, infra-red spectroscopy (IR), scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and ac susceptibility measurements. Lattice constant, grain size and density increase whereas porosity decreases with the increase in Co 2+ substitution. IR measurements show the characteristic ferrite bands. Spectral absorption bands were observed in IR spectroscopic analysis at ν 1 =564−601 cm −1 , ν 2 =486−519 cm −1 and ν 3 =551−578 cm −1 . The cation distribution estimated by the X-ray diffraction is supported by magnetization and susceptibility studies. The saturation magnetization decreases from 44.25 to 17.14 emu/g whereas coercivity remarkably increases from 240.69 to 812.14 emu/g with increasing Co 2+ substitution. The mechanisms involved are discussed.