Microstructure of Ni_0.5Zn_0.5Fe₂O₄ Nanofiber with Metal Nitrates in Electrospinning Precursor

Electrospun NiZn ferrite nanofibers have great potential due to their one-dimensional structure and electrical properties, but they have a low reproducibility resulting from many process confounders, so much research effort is needed to achieve optimized process control. For structure control, the viscosity of the precursor solution is a likely parameter. One solution is to use polyvinyl pyrrolidone (PVP) and metal nitrate to obtain the desired viscosity by increasing the nitrate content, even if the polymer content is decreased. Ni_0.5Zn_0.5Fe₂O₄ ferrite nanofiber was electrospun with various precursor conditions. Fifteen different precursor solutions, with a content of five polymers and three metal nitrates, were prepared, with precursor solutions composed of Fe(NO₃)₂·9H₂O, Ni(NO₃)₂·6H₂O, Zn(NO₃)₂·6H₂O, polyvinyl pyrrolidone (PVP), and N,N-dimethylmethanamide. The fiber diameter changed from the lowest, of 62.41 nm, to 417.54 nm. This study shows that the average diameter can be controlled using the metal nitrate concentration without a difference in crystal structure when PVP is used. In a 24.0 mmol metal nitrate precursor solution, the process yield was improved to 140% after heat treatment. There was also no significant difference in the crystal structure and morphology. This system reduces the cost of raw materials for electrospinning and increases the process yield of NiZn ferrite nanofibers.