Tunable Magnetic Properties of Glass-Coated Microwires by Initial Technical Parameters

Glass-coated microwires of three different compositions Fe
_77.5
Si
_7.5
B
₁₅
, Fe
₄₅
Co
₃₀
Si
₁₀
B
₁₅
, and Co
₆₉
Fe
₄
Cr
₄
Si
₁₂
B
₁₁
were produced by the Taylor-Ulitovsky method under water or air cooling. By changing the technological parameters such as the drawing velocity and cooling environment, the formation of different phases in the microwire metallic core was realized owing to partial crystallization, which was confirmed by X-ray diffraction analysis. A critical correlation of the wire composition, drawing velocity, and hysteresis loops was demonstrated. The combination of air cooling and low drawing velocities create the conditions of partial crystallization which may form a single or multiple crystal phases, depending on composition. On the contrary, the wires quenched in water had an amorphous state irrespectively of the drawing velocity and composition. Then, single-phase, biphase, or multi-phase state microwires could be produced. They demonstrated various types of the magnetization reversal: bistable, stepwise, and S shape with a highly enhanced coercivity. Tailoring the wire microstructure and the magnetization behavior during the fabrication process could be of considerable practical interest.