Synthesis and electromagnetic properties of Ni_0.8Zn_0.2 Fe₂O₄ nanocrystalline

The nanocrystalline Ni_0.8Zn_0.2Fe₂O₄ was synthesized by a sol-gel auto-combustion method using citric acid as chelating agent. The analysis methods of FT-IR, XRD, DSC-TG, TEM, wave-guide were used to character the gel and the products. The phenomena of melt, combustion and forming crystal for gel were investigated in the processes of thermo-decomposition. The results show that metal ions and carboxyl are coordinated by the oriented manner. The temperature of decomposition for the gel is 220°C, and the nanocrystalline is formed after the combustion of the gel. The mixture, which consists of Ni_0.8Zn_0.2Fe₂O₄ nanocrystalline and paraffin, has both dielectric loss and magnetic loss in the frequency range of 8-12 GHz. The reflectivity of spinel nanocrystalline increases and the reflectivity absorption peaks shift from high frequency to low frequency with the increase of thickness.