Effect of annealing conditions on giant magnetoimpedance of Co-rich glass-coated microwires

In this article we study the effect of conventional and stress annealing on the magnetic properties and giant magnetoimpedance (GMI) effect of Co 65.3 Si 12.0 B 10.2 Cr 8.5 Fe 3.9 Mo 0.1 microwires with low and positive magnetostriction coefficient and low Curie temperature. A remarkable tuning capacity of both GMI effect and hysteresis loops is observed for a broad range of annealing conditions up to 350 ∘ C and 320 MPa. We report appearance of double-peaks magnetic field dependencies of the GMI-ratio related with the coexistence of two different contributions originated by two different magnetic domain structure for the stress-annealed microwires. The observed experimental results are discussed in terms of the internal stresses relaxation derived from the annealing procedures, the induced magnetic anisotropy and local atomic reordering. The studies of Co-rich microwires with low and positive magnetostriction coefficient and low Curie temperature are potentially suitable for development of smart composites with embedded microwires for wireless temperature monitoring. • Influence of annealing on hysteresis loops of Co-rich microwires with low and positive magnetostriction coefficient. • Influence of annealing conditions in the GMI effect of Co-rich microwires. • Tunnability of the GMI effect of Co-rich microwires with low Curie temperature by annealing. • Double peak magnetic field dependence of the GMI ratio attributed to different coexisting magnetic anisotropy regions. • Tunability of the maximum GMI ratio and its frequency dependence by annealing.