Fabrication of Co/Al 2 O 3 Composite Nanofiber via Electrospinning with Tunable Magnetic Properties

In this paper, Co/Al 2 O 3 composite nanofibers with different Co content are fabricated by electrospinning combined with selective reduction. By controlling the Co content in the composite nanofiber, not only the fiber’s morphology, but also the magnetic properties can be well adjusted to meet different applications’ requirements. The magnetic hysteresis loops of composite nanofiber show two different types of shape, typical ferromagnetism and wasp-waisted ferromagnetism. Interestingly, the saturation magnetization, which has a close relationship with the content of magnetic component, is not simply shows an increasing tendency with the increases of Co content in the composite fiber. For the Co content below 50 wt%, the Ms value increases with the Co content. After that, the saturation magnetization decreases to a valley value at near 60 wt% Co content, then increases again. The coercivity also shows the same tendency. The results indicate that the dipolar coupling interaction plays a key role in the magnetic property adjustment of Co/Al 2 O 3 composite nanofiber.