Nanoscale characterization and magnetic reversal mechanism investigation of electrospun NiFe2O4 multi-particle-chain nanofibres

NiFe2O4 multi-particle-chain nanofibres have been successfully fabricated using electrospinning followed by calcination, and their morphology, chemistry and crystal structure were characterized at the nanoscale. Individual NiFe2O4 nanofibres were found to consist of many nanocrystallites stacked along the nanofibre axis. Chemical analysis shows that the atomic ratio of Ni : Fe is 1 : 2, indicating that the composition was NiFe2O4. The crystal structure of individual NiFe2O4 multi-particle-chain nanofibres proved to be polycrystalline with a face centered cubic (fcc) structure. The nanocrystallites in the nanofibres were revealed to have a single-crystal structure with random crystallographic orientations. The magnetic measurements reveal that the NiFe2O4 multi-particle-chain nanofibres have a coercivity force of 166 Oe. A chain of sheets micromagentism model was proposed to interpret the observed magnetic behaviour of the NiFe2O4 multi-particle-chain nanofibres. Simulation studies of the coercivity are in good agreement with the experimental results at room temperature. It is believed that this work will significantly expand the use and application of these compounds in the field of biomagnetic nano-devices and improve understanding of the magnetic origin of spinel ferrites.