Microstructure, magnetic properties and exchange–coupling interactions for one-dimensional hard/soft ferrite nanofibers

Abstract

SrFe12O19 (SFO)/Ni0.5Zn0.5Fe2O4 (NZFO) composite ferrite nanofibers with diameters about 120nm have been prepared by the electrospinning and calcination process. The SFO/NZFO composite ferrites are formed after calcined at 700°C for 2h and the composite nanofibers with various mass ratios obtained at 900°C are fabricated from NZFO grains about 16–40nm and SFO grains of 19–45nm with a uniform phase distribution. With the SFO ferrite content increasing, the coercivity (Hc) and remanence (Mr) for the composite ferrite nanofibers initially increase, reaching maximum values of 379.8kA/m (297K) and 242.2kA/m (77K), 39.1Am2/kg (297K) and 53.5Am2/kg (77K), respectively, at a mass ratio (SFO:NZFO) of 4, and then show a reduction tendency with a further increase of the mass ratio. This enhancement in magnetic properties is attributed to the competition of the exchange–coupling interaction and the dipolar interaction in the composite nanofibers.