Optimization of tunable GHz micro-antennas based on Giant magnetoimpedance

The unique magnetic properties of amorphous magnetic microwires (AMMW), in particular its interaction with microwaves by means of Giant Magnetoimpedance effect and its magnetostrictive character allow the development of tunable GHz micro-antennas useful as contactless sensing elements with applicability in many fields including biomedical. The possibility of using a single AMMW for this purpose demands the optimization and control of its electrical and magnetic properties in order to adapt them to our needs. In this work we study the changes on electrical resistance and magnetic permeability due to the stress relaxation and to the nanocrystallization induced by thermal treatments in AMMW of composition (Fe2.25Co72.25Si10B15), obtaining important variations in the sensing capability.