Nanocrystalline soft magnetic ribbons and microwires: Towards future developments in energy related applications

Abstract

The work is focused in outstanding magnetic properties as high saturation magnetization. high susceptibility, giant magneto impedance, magnetoelastic and ferromagnetic resonance, of amorphous and nanocrystalline magnetic ribbons and microwires and its possible applications related with energy saving and energy harvesting. On one side the possibility of using nanocrystalline magnetic powders as soft magnetic phase in hard-soft composites to enhance energy product (BHmx) will be analyzed. The present work provides a process for manufacturing nanocomposites with favorable microstructure to enhance maximum energy product (BHmax). It is based in the combination of a soft nanocrystalline powder with high exchanged correlation length with hard magnetic powder of similar powder particle size. Other interesting property related with nanocrystallization is magnetoelastic resonance observed in magnetic microwires. Experiments previously performed show how this materials present high magnetomechanical coupling that combined with its tiny dimensions open new possibilities in the field of harvesting energy. We have concluded that amorphous microwires have unique features as magnetoelastic resonators. Such sensors have two main advantages. The first one is their reduced size compared with the ribbon-based sensors, a typical demand in state-of the art technology. The second advantage is the fact of presenting free-bias magnetomechanical coupling which results in a free-bias magnetoelastic resonance. This feature is herein attributed to the coexistence of two different kinds of magnetic domains in the microwire.