One-dimensional SrFe12O19/SrSiO3 composite nanofibers: Preparation, structure and magnetic properties

SrFe12O19/SrSiO3 composite nanofibers with diameters around 120 nm have been prepared by calcination of the electrospun SrFe12O19/SrSiO3/PVP composite nanofibers at 800 °C for 2 h. These composite nanofibers are fabricated by the amorphous SrSiO3 and nanometer sized strontium ferrite particles with a dense and uniform nanostructure. The strontium ferrite grain size can be controlled by adjusting the strontium silicate content in the composite and decreases from about 25 to 7 nm corresponding the SrSiO3 content increasing from 13 to 44 wt%. The magnetic property of the composite nanofibers is mainly influenced by the strontium silicate content, strontium ferrite grain size and measurement temperature. It finds that the composite nanofiber magnetism is transient from the hard to the soft magnetic characteristic when the strontium ferrite grain size ranges from about 17 to 14 nm. The paramagnetic characteristics occur for SrFe12O19/SrSiO3 composite nanofibers in which the strontium ferrite grain size is around 7 nm. Compared with the magnetic parameters measured at room temperature (298 K), the specific saturation magnetization and coercivity of the composite nanofibers estimated at 77 K (in liquid nitrogen) are increased, which can be fundamentally explained based on the Bloch's law.