Improved magnetic properties of SrFe_(12)O_(19)/FeCo core-shell nanofibers by hard/soft magnetic exchange-coupling effect

摘要

Hard/soft SrFe_(12)O_(19)/FeCo composite nanoflbers with core-shell structure have been synthesized by reduction process in a hydrogen atmosphere. As the precursor, SrFe_(12)O_(19)/CoFe_2O_4 core-shell nanoflbers were prepared by coaxial electrospinning and calcination process. SrFe_(12)O_(19)/CoFe_2O_4 composite ferrites were formed after calcined at 900 ℃ for 1 h. The core-shell nanoflbers show an enhanced saturation magnetization (M_s) of 60.9 emu/g for SrFe_(12)O_(19)/CoFe_2O_4 and 68.8 emu/g for SrFe_(12)O_(19)/FeCo comparing with SrFe_(12)O_(19) nanoflbers (53.4 emu/g). The coercivities (H_c) for SrFe_(12)O_(19)/CoFe_2O_4 and SrFe_(12)O_(19)/FeCo core-shell nanoflbers decrease to 3190 Oe and 1249 Oe, respectively. The hysteresis loop for SrFe_(12)O_(19)/FeCo core-shell nanofibers shows a single-phase magnetization behavior. The improvement in magnetic properties for core-shell structure composite nanofibers is attributed to the exchange-coupling interaction between the hard and soft phases.