Fabrication and characterization of the magnetic ferrite nanofibers by electrospinning process

Since the magnetic properties of materials are greatly affected by their microstructure, nanostructuring of magnetic materials is attempted in various directions. Various processes have been used to synthesis one dimensional nanomaterials: template, hydrothermal, anodizing, and electrospinning. Among these processes, nanofibers fabricated by the electrospinning method are excellent for reproducibility and have a large aspect ratio. In addition, there have been many attempts to fabricate ceramic nanofibers with a more intricate shape using a sol-gel reaction. In this study, the electrospinning conditions for synthesizing ferrite (α-Fe2O3) nanofiber were optimized by the preliminary results of polyvinyl alcohol (PVA) nanofiber. As-spun composite nanofibers of PVA/Fe(NO3)3·9H2O were transformed to an α-Fe2O3 phase by heat treatment at 550 °C. After heat treatment, the diameters ranged from 105 nm to 124 nm in as-spun composite nanofibers, and with a decrease in PVA content after heat treatment, the diameters ranged from 59 nm to 96 nm. We investigated the magnetization properties with the microstructure of α-Fe2O3 nanofiber by a vibrating sample magnetometer. The saturation magnetization increased with an increasing diameter of the α-Fe2O3 nanofiber, and highest value of 26.2 A·m2/kg was measured in the α-Fe2O3 nanofibers with the largest diameter with a PVA content of 0.12 g/ml. The microstructure and magnetic properties of the α-Fe2O3 nanofibers were controlled by an electrospinning process, and we were able to optimize the α-Fe2O3 nanofibers for various application fields, such as electromagnetic interference and electromagnetic pulse absorbers.