Structural and magnetic transformations in amorphous ferromagnetic microwires during thermomagnetic treatment under conditions of directional crystallization

As produced glass-coated ferromagnetic microwires typically have an amorphous state and demonstrate ultra-soft magnetic properties. For many applications, microwires with strong hard magnetic properties are of interest. A giant increase in coercivity has been recently reported for microwires subjected to directed crystallization. This paper confirms the coercivity increase up to 42 kA/m for wires of composition Fe4.3Co67.7Si11B14Cr3 after magnetic-field assistant directed crystallization. To understand the effect of the directional crystallization on wire magnetic properties and to develop the reliable annealing technology the structural and mechanical transformation occurring during various stages of the annealing processes were investigated.