Abstract: This paper studied the Giant Magnetoimpedance (GMI) and field sensitivity (ζ) of Cobased microwires with different diameters and under different annealing current densities, which was prepared by the TaylorUlitovsky method. The results showed that with the increase of diameters of the microwires the GMI and ζ both increase first and then decrease. The best soft magnetic property is obtained for the microwires with 29 μm in diameter. The highest field sensitivity (602 %/Oe ) is found under 120 A/mm² current annealing.

Key words: soft magnetic property, optimization, glass covered microwires, soft magnetic property, optimization