Combustion reaction synthesis and characterization of nanocrystalline CdCr0.5Fe1.5O4 ferrite using different organic fuels

Nanocrystalline cadmium-chromium ferrite (CdCr₀.₅Fe₁.₅O₄) was successfully synthesized via the sol-gel auto-combustion method to investigate the influence of different organic fuels on the structural, morphological, and magnetic properties. Four identical compositions were prepared using citric acid (CA), glycine (GA), a glycine-urea mixture (GU), and glycine without pH adjustment (GD). X-ray diffraction (XRD) analysis confirmed the formation of a single-phase face-centered cubic (FCC) spinel structure in all samples. Notably, the sample prepared with citric acid exhibited a significant reduction in grain size ( D  = 4.24 nm), and degree of crystallinity compared to the others. Vibrational spectroscopy (FTIR) highlighted a broadening and overlapping of the two main absorption bands corresponding to the tetrahedral A- and octahedral B-sites. Transmission electron microscopy (TEM) analysis indicated a high degree of agglomeration for the nano powders synthesized by using citric acid, whereas those prepared using glycine and urea consisted of fine spherical and rectangular nanoparticles. Vibrating sample magnetometer (VSM) confirmed that the value of coercive field ( H _c = 1063.7 G) for the (CA) sample is about five times higher than the other samples, which is attributed to enhanced grain boundary effects. In contrast, samples with larger crystallite sizes (GU, GD) exhibited higher saturation magnetization due to a greater volume fraction of magnetic material.