Giant magnetoimpedance (GMI) and the GMI effect of a Co-based fiber beam were investigated in the frequency range of 0.1–10 MHz, and the influence of distance between adjacent fibers on the distribution of the surface circumferential magnetic field and GMI effect was analyzed. Compared with a single fiber, the distribution of the surface magnetic field of paralleled fibers is non-uniform, induced by magnetic interaction between metal fibers. The originally uniformly distributed circumferential magnetic field changes into two obvious coexisting parts: one stronger and one weaker. The results prove that the strengthened circumferential magnetic field determines the GMI effect and sensitivity. It is found that the maximum surface of the circumferential magnetic field is reinforced by 88% when the four fibers are as closely parallel as possible; the GMI effect is greatest under higher field sensitivity. At 5 MHz, the sensitivity of the four-fiber beam reaches 3090 V/T, an increase of 277% compared with a single fiber. However, the magnetic interaction fades with the increase in distance between fibers and as the distribution of the surface magnetic field becomes even. The maximum magnetic field also becomes gradually equal to the level of a single fiber. When the distance is 1 mm, the maximum surface magnetic field is increased by 3.2%, and the improvement in the GMI effect is correspondingly slight. Therefore, a strong magnetic interaction among fibers can improve the intensity of the surface circumferential magnetic field and give rise to a fine GMI effect and high field sensitivity in Co-based metal fibers.
Giant magnetoimpedance Metallic fiber Sensitivity Magnetization Magnetic interaction Sensor
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The authors would like to express their appreciation to Prof. Yelon and Menard from University of Montreal of Canada for support and assistance in impedance experiment. This work was financially supported by the Scientific Research Project of Ningxia Higher Education Institutions (NGY2015056), Key Scientific Research of North Nationalities University (2015KJ15) and National Natural Science Foundation of China (Nos. 51604159, 51365046).
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