Temperature evolution of magnetic susceptibility during devitrification of Cu-free HITPERM alloy

Development of structural and magnetic properties of the Fe44.5Co44.5Zr7B4 alloy during its successive devitrification from amorphous to nanocrystalline state was investigated. Temperature independence of the initial susceptibility in a wide temperature range (20–600 °C) was observed. The origin of such susceptibility behavior was described through the compensation of lowering exchange interaction between nanocrystalline grains and their magnetization at increased temperatures. The stabilization of the domain structure, due to atom pair directional ordering, was confirmed by measurements of the amplitude dependence of susceptibility in a wide field range, where the initial susceptibility remains constant (Perminvar effect).