Rapidly Solidified Magnetic Nanowires and Submicron Wires

Magnetically soft amorphous glass-coated microwires are suitable for numerous sensor applications. Their typical dimensions – metallic nucleus diameter of 1 to 50 m and glass coating thickness of 1 to 30 m – make them promising candidates for high frequency applications, especially given their sensitive giant magneto-impedance (GMI) response in the MHz and GHz ranges (Torrejón et al, 2009). The magnetic properties of amorphous microwires are determined by composition, which gives the sign and magnitude of their magnetostriction, as well as by dimensions – metallic nucleus diameter, glass coating thickness, and their ratio – which are extremely relevant for the level of internal stresses induced during preparation. The magneto-mechanical coupling between internal stresses and magnetostriction is mainly responsible for the distribution of anisotropy axes and domain structure formation. Microwires generally display a core-shell domain structure in their metallic nucleus, with orthogonal easy axes, e.g. axial in the core and circumferential or radial in the shell, as schematically shown in Fig. 1.