Microstructure, mechanical and magnetic properties of melt extracted Fe-6.5Â wt.%Si microwires

Fe-6.5 wt.%Si microwires with 40 ∼ 100 μm diameter and 2 ∼ 30 cm length were successfully fabricated by the melt extraction technique. The microwires possess a D-shaped cross-section and exhibit high ductility at room temperature due to rapid solidification inhibiting the formation of ordered phases. The fan-like microstructure, which forms as a result of a fan-like temperature gradient, consists of equiaxed crystals in the centre and columnar crystals along the radial direction. Significant dependence of magnetic moment on the sample spatial orientation with respect to the magnetic field has been observed from M-θ curves, which exhibit a “W” shape from 50 Oe to 7000 Oe due to shape anisotropy effects and a “Double-W” shape from 8000 Oe to 10000 Oe due to a compromise between the demagnetizing field energy (Ed) and external field (Zeeman) energy (Eh).