Template synthesis and magnetic properties of highly aligned barium hexaferrite (BaFe12O19) nanofibers

Using electrospun poly(ethylene terephthalate)/citric acid (PET/CA) microfibers as the template, highly aligned barium hexaferrite (BaFe12O19) nanofibers with diameters of ca. 800 nm and lengths up to 2 cm were synthesized by sol-gel precursor coating technique and subsequent high temperature calcination. Structural and morphological investigations revealed that individual BaFe12O19 nanofibers were composed of numerous nanocrystallites stacking alternatively along the nanofiber axis, the average grain size was ca. 225 nm and the single crystallites on each BaFe12O19 nanofibers were of random orientations. The formation mechanism of aligned BaFe12O19 nanofibers was proposed based on experiment. The magnetic measurement revealed that the aligned BaFe12O19 nanofibers exhibited orientation-dependent magnetic behavior with respect to the applied magnetic field. The magnetic anisotropy with the easy magnetizing axis along the length of the nanofibers was due to the shape anisotropy. Such aligned magnetic nanofibers can find relevance in application requiring an orientation-dependent physical response. (c) 2013 Elsevier B.V. All rights reserved.