A new type of longitudinally driven GMI effect of FeCo-based alloy

Abstract

On investigating the longitudinally driven GMI effect of the DC annealed Fe 36 Co 36 Nb 4 Si 4.8 B 19.2 alloy ribbon, the current density was 3.2×10 7 A/m 2 , the GMI effect responds sensitively (the sensitivity is as high as 2440.2%/(A·m −1 )) to weak magnetic field after a 600-second annealing. The experimental result shows that the sensitivity is closely related to annealing current density, driven current frequency and eroded thickness.GMI effect, current annealing, sensitivity, magnetic domain structureThe GMI (Giant Magneto-impedance) of amorphous and nanocrystalline soft magnetic material has attracted technologists all over the world for its potential application on high-performance magnetic sensor and magnetic recording head [1][2][3][4][5] . Yabukami et al. have proved the practical value of GMI by developing the GMI magnetic sensor with high sensitivity and signal-to-noise ratio [6][7][8] . However, GMI's poor sensitivity and linearity at zero magnetic field limited its application. Recently, RosalesRivera et al. reported GMI effect's "three peaks" behavior in research on FeCrNbCuSiB [9][10][11] . It responds sensitively to weak magnetic field around a frequency between 8 and 20 MHz, which lends new idea to the design and development of high-sensitive magnetic switch and magnetic recording head. The reason for this behavior is to be investigated.We found the similar "three peaks" behavior in investigating the longitudinally driven GMI effect DC annealed Fe 36 Co 36 Nb 4 Si 4.8 B 19.2 alloy ribbon, and called it TGMI (Tip Giant Magneto-impedance) for the magnetoimpedance ratio curve shapes like a tip from the foundation. We also studied how the DC density, driven current frequency and eroded sample thickness influence TGMI.