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 degrees 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.