The annealing induced evolution of structure and magnetic properties of glass-coated microwires (GMW) made of FeNbCuBSi alloy were studied. The microwires were produced by a modified Taylor method. The annealing temperatures were varied from 800 to 890K. In their as-cast state, all microwires featured perfect square hysteresis loops. After annealing, the GMW hysteresis loop width decreased thus indicating the alloy devitrification and the nanocrystalline phase growth. The grain size measured in TEM studies was 10–15nm. The hysteresis loops of GMW with 13% Si content remained square-shaped in the whole range of annealing temperatures, while in the case of GMW with 16% Si content, increasing Ta caused the loop transformation to a flat, anhysteretic one. After the hysteresis loop underwent the square-to-flat transformation, an enhancement in GMW high frequency properties had been observed.

The technique of magnetic pulse compression (MRC) is widely used in numerous applications like high energy pulse lasers, electron beam accelerators, pulse sources for X-rays tubes etc.

High-frequency properties of toroid cores made of amorphous glass-coated micro-wire are reported in this work. The frequency dependencies of permeability and loss factor in the 0.1–30 MHz range are presented. We studied also the dependence of specific losses on flux density. The real part of effective permeability lies in the range of 150–1000, and the value is nearly constant in a broad frequency range (up to 30 MHz). The imaginary part demonstrates a monotonous increase up to 30 MHz for all samples. Specific losses of micro-wire cores are small in comparison to those of ferrite cores.

Static and high-frequency 1–30 MHz properties of the (Co100−xMnx)75B15Si10 microwires cast using the modified Taylor’s technique are reported. The hysteresis loop and the frequency dependence of permeability indicate that the longitudinal magnetization process occurs by coherent rotation of the moments. The values of static permeability are in good agreement with those predicted by the theory of ferromagnetic resonance where damping is taken into account. We observed a close correlation between the static permeability and the high-frequency limit (the frequency up to which the real part of permeability is still constant). For glass-coated CoMn microwires, this limit is considerably higher than that given by the Snoek equation.