Fabrication and Characterization of Mn_0.5Zn_0.5Fe₂O₄ Magnetic Nanofibers

Mn_0.5Zn_0.5Fe₂O₄ Magnetic nanofibers were fabricated by calcining electrospun polymer/inorganic composite nanofibers and characterized by thermogravimetric and differential thermal analysis, x-ray diffraction, field emission scanning electron microscopy, high resolution transmission electron microscopy and a vibrating sample magnetometer. The experimental results show that the pure spinel structure is basically formed when the composite nanofibers are calcined at 450°C for 2h. With the increasing calcination temperature, both the saturation magnetization and coercivity of nanofiber samples increase initially along with the growth of Mn_0.5Zn_0.5Fe₂O₄ nanocrystals contained in the nanofibers. However, when the calcination temperature reaches 550°C, the saturation magnetization of nanofibers starts to dramatically decrease owing to the formation of the α-Fe₂O₃ phase at this temperature. The prepared Mn_0.5Zn_0.5Fe₂O₄ nanofibers calcined at 500°C for 2h have diameters ranging from 100 to 200nm. Their saturation magnetization and coercivity are 12.37emu/g and 4.81kA/m at room temperature, respectively.