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A combination of high energy ball milling, vacuum filtering and sedimentation processes has been demonstrated to be a useful approach to reduce, in a controlled way, the length of as-cast Fe73.5Si13.5Nb3Cu1B9 amorphous magnetic microwires (MWs) and annealed material at 550 ºC in nitrogen condidions. Homogeneous compositional microstructures with fairly narrow size distributions between 1300 µm and 11.7 µm are achieved exhibiting tunable response as a soft magnetic material and as a microwave absorber. From the magnetic perspective, the soft magnetic character is increased with smaller length of the MWs whereas the remanence has the opposite behavior mainly due to the structural defects and the loss of the shape anisotropy.From the microwave absorption perspective, a novel potential applicability is tested in these refined microstructures. This innovation consists of coatings based on commercial paints with a filling percentage of 0.55% of MWs with different lengths deposited on metallic sheets. Large attenuation values around -40 dB are obtained in narrow spectral windows located in the GHz range and their position can be varied by combining different optimized lengths of MW. As an

A study on the interislands interaction in granular Fe͑110͒ thin films grown on c-sapphire as a function of the islands size and the capping layer induced magnetization is presented. Islands size (ranging from 10 to 50 nm in diameter) and physical contact between them can be monitored with the deposition time. While Al and MgO cappings do not modify the magnetic hysteresis loop of free islands surface, Pd and Pt give rise to a superparamagnetic-ferromagnetic transition in structures formed by small islands and a stronger interisland coupling in those formed by larger ferromagnetic islands. This improvement in the exchange interactions between islands is due to the induced magnetization of Pt and Pd localized at the interfaces between Pt-Fe͑Pd-Fe͒ as evidenced by polar Kerr spectroscopy measurements and simulations.

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