Physical properties and giant magnetoimpedance sensitivity of rapidly solidified magnetic microwires

The relation between the magnetoimpedance and the magnetic properties of a wide set of soft magnetic microwires from several sources has been studied. Magnetic properties were obtained by vibrating sample magnetometry and ferromagnetic resonance spectroscopy. The magnetoimpedance voltage sensitivity of each sample, the criterion of interest for high sensitivity magnetometer design, was then evaluated at several frequencies and drive currents. It appears that all samples possess roughly similar properties, regardless of their fabrication process or chemical composition. The voltage sensitivity of the samples obtained from experimental measurement is compared with a simple model of sensitivity. The general trends predicted by the model provide useful insights for materials optimization. Averaged sensitivity over the sample set is around 10 kV/T/cm at 10 MHz. The critical importance for sensitive magnetometry of the maximum excitation current permissible in each wire is also highlighted.