The stress dependence of Barkhausen noise in Fe₈₁B_13.5Si_3.5C₂ Metglas

The Barkhausen noise (BN) profile of Fe₈₁B_13.5Si_3.5C₂ Metglas changes from single to double peaks with applied tensile stress. The second harmonics during the magnetization process under various stresses confirm that the single and double peaks on the BN profiles can be attributed to domain nucleation/annihilation. The variation of the initial permeability with tensile stress indicates that the volume fraction of longitudinal domains along the stress direction increased up to a stress of 20 MPa (stage I) and then it remained constant with further stressing, v∥ (σ) ≈ 1 (stage II). The total BN activity during a half (B-H) loop with tensile stress, transient also at about 20 MPa, can be characterized by a (BN)_tot ∞ e^βσrelationship, where the exponents are β₁ = 1.761 × 10^-2 and β₂ = 1.758 × 10^-3 for stages I and II, respectively. An analysis of (BN)_tot in stage II showed that the number of domains involved in the domain nucleation/annihilation is proportional to σ^1/2.