Study of Stress-Annealing Enhancement of Magnetoimpedance Effect in $Fe_{89.8}Ni_{1.5}Si_{5.2}B_{3}C_{0.5}$ Metallic Glass Ribbons

In this study, the magnetoimpedance effect in magnetically soft $Fe_{89.8}Ni_{1.5}Si_{5.2}B_{3}C_{0.5}$ metallic glass ribbon samples with significant decrease in atomic percentage of metalloids content (less than 10 at.%) was investigated. Thermal treatments were performed by stress-annealing technique of up to 693 K/475 MPa/30 min. The critical frequency of about 600 kHz was observed as the point with the initial increase in magnetoimpedance ratio. Significant improvement of magnetoimpedance-response reaching the value ΔZ/Z=25% after stress-annealing at 693 K/130 MPa/30 min was recorded in samples with still amorphous structure at driving frequency of 4 MHz. The highest magnetoimpedance-element sensitivity was found for low magnetic field intensity (H ≤ 1 kA/m), where values of about 12%/kA/m were attained.