Tailoring Magnetic Properties and Magnetoimpedance Response in Nanocrystalline (Fe3Ni)81Nb7B12 Ribbons for Sensor Applications

Today, there is an increasing demand for progress in the magnetoimpedance (MI) response of cost-effective soft-magnetic materials for use in high-performance sensing devices. In view of this, we investigate here the field-annealing effects on soft-magnetic properties, magnetoimpedance response, and field sensitivity in the nanocrystalline (Fe3Ni)(81)Nb7B12 alloy ribbons. We observe that within the low-frequency regime, between 2 and 5 MHz, the zero-field-annealed (ZFA) ribbons exhibit the highest magnetoimpedance values. By magneto-optical Kerr effect measurements, we show that this result stems from the formation of irregular transversally patched magnetic domains after annealing, which in turn explains the induced transverse anisotropy necessary to increase the GMI response. In addition, we discuss this increment in terms of skin effect. Moreover, we report that the highest sensitivity of ca. 189%/(kA/m)-15%/Oe-is achieved for the field-annealed samples whose magnetic field was applied transverse to the ribbon axis. These findings are of practical importance to develop and refine highly sensitive magnetic sensors.

Automated summary

In this study, the effects of field annealing on the soft-magnetic properties, magnetoimpedance response, and field sensitivity of nanocrystalline (Fe3Ni)(81)Nb7B12 alloy ribbons were investigated. It was found that the zero-field-annealed (ZFA) ribbons exhibited the highest magnetoimpedance values within the low-frequency range of 2-5 MHz, which was attributed to the formation of irregular transversally patched magnetic domains after annealing. The highest sensitivity was achieved for the field-annealed samples with magnetic field applied transverse to the ribbon axis.