Engineering of magnetic softness and giant magnetoimpedance effect in Fe-rich microwires by stress-annealing

Magnetic softness and giant magnetoimpedance (GMI) effect of Fe-rich microwires has been considerably improved by stress-annealing: we obtained maximum GMI ratio about one order higher than in as-prepared Fe rich microwire and of the same order as in as-prepared Co-rich microwire. High enough bias current allows drastic increasing of GMI ratio of Fe-rich microwires up to 120% and off-diagonal GMI effect but also produces irreversible changes of GMI effect related to Joule heating of the samples. For interpretation of observed dependences we considered internal stresses relaxation after annealing interplay of compressive back-stresses arising after stress annealing and axial internal stresses. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.