Influence of the divalent and trivalent ions substitution on the structural and magnetic properties of Mg0.5−xCdxCo0.5Cr0.04TbyFe1.96−yO4 ferrites prepared by sol–gel method

Abstract

A series of the divalent and trivalent co-substituted Mg0.5−xCdxCo0.5Cr0.04TbyFe1.96−yO4 spinel ferrite systems (where x=0–0.5 in steps of 0.1 and y=0.00–0.10 in steps 0.02) are synthesized by sol–gel auto combustion method. The product materials were characterized by the thermo gravimetric analysis and differential scanning calorimetry (TGA/DSC), Fourier transform infrared spectra (FTIR), nitrogen adsorption (BET), X-ray diffraction (XRD), scanning electron microscope (SEM), atomic force microscopy (AFM) and vibrating sample magnetometer (VSM). The X-ray diffraction patterns and Fourier transform infrared spectroscopy confirm spinel nanocrystalline phase. The crystallite size is determined by Scherer's formula from 36.6 to 69.4nm. The X-ray density is found in the range of 5.09–6.43(g/cm3). The morphological features are studied using scanning electron microscope and AFM. Saturation magnetization (Ms) and remanence (Mr) magnetization extracted from M–H loops exhibit the decreasing trends 21.4–16emu/g and 9.1–6.3emu/g, respectively. A significant decrease in the intrinsic parameters is observed in the prepared samples due to the weakening of the A–B interaction as iron enters into the tetrahedral A-site. The coercivity lies in the range of 300–869Oe as a function of co-substitution contents. The coercivity of the sample with x=0.1, y=0.02 was found maximum i.e. 869Oe. The obtained results suggest that the investigated materials may be potential candidates for high density recording media applications.