Blowing‐Combustion Synthesis of Sponge‐like Ni_xZn_1−xFe₂O₄ and Its Structural and Magnetic Properties

Abstract

Spinel ferrites have been widely used in various fields, among which nickel‐zinc (NiZn) ferrites have drawn much attention due to their high electrical resistivity as well as low eddy current loss. To accommodate highly‐integrated modern electronic devices, the preparation methods for nano/micro‐sized NiZn ferrites have been widely discussed. Nevertheless, these current synthesis routes are usually cost/time‐consuming, which hinders their large‐scale production for practical applications. Herein, we present a facile, low‐cost synthesis strategy for NiZn ferrites (NixZn1−xFe2O4, x=0, 0.25, 0.5, 0.75 and 1) through a blowing‐combustion method. The effect of Ni/Zn molar concentration on the structure, morphology as well as magnetic properties has been thoroughly investigated through X‐ray diffraction, Raman spectroscopy, scanning electron microscopy and vibrating sample magnetometer. Thanks to the synergetic effect of the pure phase and moderate Ni molar concentration, the Ni0.75Zn0.25Fe2O4 shows an enhanced saturation magnetization of 44.98 emu/g. More importantly, this blowing‐combustion method may also be commonly applied to other spinel ferrites with different stoichiometric ratios and heteroatom doping.

Combustion Synthesis of Porous NiCuZn Spinel Ferrite Hierarchies and Their Magnetic Properties

“…As the temperature increased, gases released from the nitrates blew the molten PVP into numerous bubbles, forming a 3D sponge structure. After annealing at a higher temperature (800 °C), the metal ions were in situ converted into corresponding metal oxides while the sponge morphology was well maintained [7b] . However, the current combustion method usually requires multistep processes (evaporation of the solution/gel and sintering) and results in irregular bulk grain size (microscale), and the as‐synthesized spinel ferrites show limited saturation magnetization and high coercivity.…”