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There is a pressing need for improving of the high-frequency magneto-impedance effect of cost-effective soft magnetic materials for use in high-performance sensing devices. The impact of the stress-annealing on magnetic properties and high frequency impedance of Fe-rich glass-coated microwires was studied. Hysteresis loops of Fe-rich microwires have been considerably affected by stress- annealing. In stress-annealed Fe- rich microwire we obtained drastic decreasing of coercivity and change of character of hysteresis loop from rectangular to linear. By controlling stress-annealing conditions (temperature and time) we achieved drastic increasing (by order of magnitude) of giant magnetoimpedance ratio. Coercivity, remanent magnetization, diagonal and of-diagonal magnetoimpedance effect of Fe-rich microwires can be tuned by stress-annealing conditions: annealing temperature and time. Observed experimental results are discussed considering relaxation of internal stresses, compressive “back-stresses” arising after stress annealing and topological short range ordering.

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The values of the magnetostriction constant, l s , of Co-based glass-coated microwires have been investigated by using the small-angle magnetization rotation (SAMR) method. Performing the systematic measurements, we were able to choose the appropriate measurement conditions achieving a highprecision result. From the dependence of the evaluated magnetostriction coefficient on annealing conditions, we evaluated the influence of the internal stresses on the magnetostriction coefficient value and the influence of the heat treatment on the magnetostriction coefficient of nearly zero magnetostrictive Co-based microwires. We observed changes of the magnetostriction value and sign after annealing. The maximum on the dependence of the magnetostriction coefficient on annealing time is explained considering superposition of the stress relaxation and ordering and beginning of the crystallization process.

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