Magnetic and Structural Properties of SrFe12−xCrxO19 (x = 0, 0.25, 0.5, 0.75, 1) Hexaferrite Powders Obtained by Sol–Gel Auto-Combustion Method

Abstract

The crystalline structure and magnetic properties of chromium substituted hexagonal strontium ferrite, SrFe12−xCrxO19 (x = 0, 0.25, 0.5, 0.75, 1), nanoparticles have been investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM). These materials were prepared by the chemical sol–gel auto-combustion method. From the structural analysis, it was observed that the non-magnetic phase α-Fe2O3 appears after x ≥ 0.5 and remains to be a hexagonal magnetoplumbite phase for x < 0.5. Various parameters such as lattice constants (a and c) were calculated from the XRD data. The coercively H c initially decreases and then increases with increasing chromium concentration. The saturation magnetization exhibits an increase as the chromium content increases up to (x = 0.25) and then decreases with increase in the Cr content ion from 75.19 to 61.66 emu/g due to the substitution of Fe3+ ions by less magnetic Cr3+ ions. Furthermore, M r continually decreases with increase in the Cr content.