Correlation of the heat treatment feature and magnetic properties of the SrFe12O19@ZnFe2O4 core-shell nanofibers

Abstract Nanocomposite SrFe12O19@ZnFe2O4 with core-shell structure has been synthesized in one step via coaxial electrospinning followed by heat treatment in air. The samples comprise two phases, the structure change from fiber coated particles to core-shell fibers, and finally form a scattered sheet structure. The inner diameter of the nanofiber with core-shell structure is 100 nm and the outer diameter is 170 nm, two-phase coupling interface is obvious, and the length of the nanofiber can reach 1.8 μm. The magnetic properties of the composites show a decreasing trend after upward, reaching the highest Ms (43 emu/g) and Hc(4524 Oe) at 900 °C, which is better than for other materials with various morphologies such as sheet and particle. The hysteresis loop at 900 °C shows a single-phase-like magnetic characteristic, indicating the existence of effective exchange coupling. This study provides a basis for the preparation of hard-soft nanocomposite ferrite fibers with controlled core-shell structure, excellent exchange coupling and outstanding magnetic properties.