Sol–gel auto-combustion synthesis of SiO2-doped NiZn ferrite by using various fuels

A nitrate–chelate–silica gel was prepared from metallic nitrates, citric acid and tetraethoxysilane (TEOS) by sol–gel process with different complexing agents such as glycine, hydrazine and citric acid, and it was further used to synthesize Ni0.5Zn0.5Fe2O4/20 wt% SiO2 nanocomposites by auto-combustion. The effect of varying complexing agent on the structural and magnetic properties of the composites was studied by FTIR, 29Si CP/MAS NMR, XRD, TEM, EPR and SQUID measurements. The complexing agent in the starting solution influenced the magnetic interaction between NiZn ferrite and silica, and then determined on the particle size. Further, the complexing agent type had a direct effect on the EPR parameters (ΔHPP, g-factor and T2) and SQUID parameters (Ms, Mr and Hc) of the as-synthesized powder.