Structural heterogeneity, β relaxation and magnetic properties of Fe-Zr-B amorphous alloys with Si and Cu additions

Despite numerous studies on β relaxation of amorphous alloys, the relationship between structural heterogeneity and β relaxation and the effect on magnetic properties of Fe-based amorphous alloys is still unknow. In this work, the structure and magnetic properties of Fe _84-xZr ₆B ₁₀M _x (M = Si, Cu; x = 0, 0.6, 1 at%) amorphous alloys were investigated. With the increase of Si content, the negative value of average chemical affinity (∆ H ^chem) of the alloys is increased, leading to the synergetic enhancement in structural heterogeneity and β relaxation. In addition to this, the increase of liquid-like regions (LLRs) reduces saturation magnetic flux density ( B _s ) and increases coercivity ( H _c). However, the addition of Cu element decreases the negative value of ∆ H ^chem of the alloys, resulting in weakening of structural heterogeneity and β relaxation synergetically. The reduction of LLRs has resulted in increase in B _s. Moreover, Fe-Cu atom pairs with positive enthalpy of mixing increases the local density of quasi dislocation dipoles (QDDs), resulting in the increase of H _c.