Structural changes in ferromagnetic microwires (PrDy)(FeCo)B under vacuum annealing

Vacuum annealing of amorphous (PrDy)(FeCo)B microwires causes a redistribution of chemical elements in areas with different types of crystal lattice. The bulk of the annealed microwire has a tetragonal structure and corresponds to the alloy (PrDy)$_2$(FeCo)$_{14}$B. Nonequilibrium inclusions with a body-centered cubic lattice (BCC) are formed in the annealed microwire. These inclusions have an excess of Fe and Co and a depletion of rare earth elements Dy and Pr compared to the material of the surrounding tetragonal lattice. Thermal adjustment of the chemical, phase and structural composition of the microwires allows obtaining nonequilibrium states of the alloy with modified magnetic properties.