Fabrication of soft ferromagnetic multilayer‐structure sensor for measurement of microampere direct currents

Abstract

Quantitative measurements of direct currents are achieved by using multilayer-structure current sensor (NiFe/Cu/NiFe/Cu/Cr) carrying wide-frequency alternating currents (20 Hz-100 MHz). It was found that the impedance of the current sensor was reduced in the presence of direct currents, and decreased with increasing direct currents at medium frequency. In addition, the measurement sensitivity increased with increasing the amplitude of the alternating current. The authors also observed that the resistance variation in response to the direct currents was much larger than that of impedance and reactance at medium frequency. This current sensor was capable of measuring the direct current of at least 40 μA, exhibiting a resistance variation of 0.00674 Ω. Consequently, the ferromagnetic multilayer films may serve as a super-sensitive current sensor for the measurement of currents.

Non-Contact Current Sensing System Based on the Giant Magnetoimpedance Effect of CoFeNiSiB Amorphous Ribbon Meanders

“…The meanders have been shown to significantly improve the GMI ratio and sensitivity compared to strip type [ 29 , 30 , 31 , 32 , 33 ] and can effectively utilize the element space to have higher spatial resolution [ 34 ], which is a more superior structure. Tao Wang et al utilized multilayer meander films (NiFe/Cu/NiFe/Cu/Cr) to carry wide-frequency alternating currents (20 Hz–100 MHz) for quantitative measurements of DC currents [ 35 ]. It was found that the impedance of the current sensor was reduced in the presence of direct currents and decreased with increasing direct currents at medium frequency.…”

Line spacing effect on the giant magnetoimpedance behavior on microribbon with meander type: a comparison of theory and experiment

“…Meanders based on the giant magnetoimpedance (GMI) effect have been reported several times because of their potential applications in the current detection, nondestructive inspection, pressure sensing measurement and biomagnetic monitoring (Nakai, 2019;Wang et al, 2019aWang et al, , 2019bZhi et al, 2017). The meander configuration can use the space of the element and consequently has a higher spatial resolution (Kikuchi et al, 2020).…”

“…Meanders based on the giant magnetoimpedance (GMI) effect have been reported several times because of their potential applications in the current detection, nondestructive inspection, pressure sensing measurement and biomagnetic monitoring (Nakai, 2019; Wang et al. , 2019a, 2019b; Zhi et al.…”