Tayloring magnetic anisotropy of glass-coated amorphous microwires with positive magnetostriction by current annealing
Heat treatment has long known to be well effective in tailoring magnetic properties of amorphous glass-coated microwires, thence, magnetic properties can be tailored or controlled via changing magnetic anisotropy using appropriate annealing process. Consequently, controlling magnetic anisotropy can improve the sensitivity of wires to become adequate for sensing applications. In this work, we studied the effect of dc current applied on Co-based amorphous glass-coated microwires with positive magnetostriction to investigate the Giant Magnetoimpedance (GMI) effect and magnetic hysteresis properties. We presented that annealing process could be very effective to control the magnetic properties of the concerned microwires for particular sensing applications. The microwires under investigation were produced by the standard Taylors-Ulitovski method. During the annealing process, a circumferential anisotropy is induced and the magnetostriction constant changes continuously. Moreover, a helical type of magnetic anisotropy in the concerned wires and then a strong control the GMI effect can be achieved by electric current annealing. When the specific GMI effect is achieved, rectangular hysteresis loops have also been observed, due to the annealing process. Additionally, magnetoimpedance behavior remarkably changed from a single bell-shaped to two symmetrical peaks one, with a notable in the magnetoimpedance magnitude. This specific effect can help to make the amorphous microwires the best candidates for sensors and devices for particular sensing applications, especially for microwave-based applications.