Structural, morphological, and magnetic studies of spinel ferrites derived from layered double hydroxides

Herein, we reported a successful synthesis of spinel ferrites MFe2O4 (M = Ni, Co, and Mg) nanopowders through heat treatment of carbonate-intercalated layered double hydroxide (MFe–CO3–LDH) precursors at 600 and 1000 °C for 2 h. The physicochemical properties of as-synthesized LDHs and resulting calcined products were investigated using X-ray diffraction, thermogravimetric/differential thermal analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, magnetic measurements and Mössbauer spectrometry. The results reveal the formation of a single-phase spinel crystal structure of space group Fd-3m. The effect of calcination temperature on the structural and magnetic properties of ferrite nanoparticles was discussed in detail. The Ni2+, Co2+, and Mg2+ substitution on the structure resulted in significant changes in the crystal composition, surface morphology, particle size, and magnetic properties of spinel ferrites. Furthermore, the effects of calcination on the structural and magnetic phase transformation of iron-containing LDH precursors have been also studied by Mössbauer spectrometry at room temperature. The M(H) curves at 5 K revealed a soft magnetic behaviour for both Ni and Mg calcined products, while Co spinel ferrite shows wasp-waist magnetic nature which is discussed in present study. By comparing to reported works in literature, the calcination effect on the present LDH samples has relatively improved the saturation magnetization property.