Stress Dependence of Switching Field during the Devitrification of Finemet-Based Magnetic Microwires

We have studied the influence of the thermal treatment on the stress dependence of the switching field during the devitrification of amorphous Fe_73.5Cu₁Nb₃Si_11.5B₁₁ microwires. The non-destructive test (NDT) method based on the magnetization reversal of ferromagnetic materials is sensible to changes in microstructural characteristics and the stress state of the material. The stress dependence has been explained considering the magnetoelastic contribution to the switching mechanism which is modified applying the tensile stresses and changing the magnetostriction constant and strength of the internal stresses distribution through thermal treatments. We show that by properly setting a frequency during the measurement and adequate treatment of the sample, it is possible to vary the sensitivity, magnitude and stress dependence of the sample. Keywords: Magnetic bistability, glass-coated microwires, switching field, stress sensor