Optimization of high frequency magnetoimpedance effect of Fe-rich microwires by stress-annealing

We present comparative studies of magnetic properties and giant magnetoimpedance (GMI) effect of Fe and Co-rich microwires. As-prepared Co-rich microwires present much higher GMI ratio. The impact of the stress-annealing on magnetic softness and high frequency magnetoimpedance effect of Fe-rich microwires has been studied. The large improvement of the magnetoimpedance response in a wide frequency range by the stress-annealing is observed. We have achieved GMI ratio increase by an order of magnitude after stress-annealing of Fe-rich microwire. Observed stress-induced anisotropy and related changes of magnetic properties are discussed considering internal stresses relaxation and “back-stresses”.