Synthesis of Ni$_{0.4}$Zn$_{0.6}$Fe$_{2}$O$_{4}$ spinel ferrite and microwave adsorption of related polymer composite

Nickel-zinc ferrites are important industrial materials in the production of various types of microwave devices; therefore, studies of new methods of obtaining functional ceramic on their basis are of great interest at present. In this work, soft magnetic ceramics based on Ni$_{0.4}$Zn$_{0.6}$Fe$_{2}$O$_{4}$ spinel ferrite with low values of the coercive force were successfully obtained under various sintering modes (1000 and 1100$^{\circ}$C, holding time — 16 hours) based on nanostructured pre-ceramic ferrite powder synthesized by the solution combustion method. The initial powder and sintered ceramics were investigated by EDX, SEM and PXRD methods. The electromagnetic parameters of the final product were investigated by vibration magnetometry and using the method of rectangular waveguide transmissions in the X-band. It was shown that, depending on the selected sintering mode, it is possible to obtain magnetic ceramics with an average grain size in the range from 1 to 3 $\mu$m and with values of the coercive force ($H_{c}$) from 16.32 to 19.41 Oe, remanent magnetization ($M_{r}$) from 3.39 to 4.31 emu/g and saturation magnetization ($M_{s}$) from 67.90 to 78.42 emu/g. After the preparation of a ferrite-polymer composite with different content of Ni$_{0.4}$Zn$_{0.6}$Fe$_{2}$O$_{4}$ (0-50 wt%), it was found that the highest absorption characteristics of electromagnetic waves were observed for the sample with 40 wt% of spinel ferrite obtained at 1100$^{\circ}$C, 16 hours sintering mode.