Spin-valve giant magneto-resistance film with magnetostrictive FeSiB amorphous layer and its application to strain sensors

Abstract

Giant magneto-resistance (GMR) spin-valve films with an FeSiB/CoFeB free layer were fabricated to detect applied strain in a GMR device. The magnetostriction constant of FeSiB was experimentally determined to have 32 ppm, which was one order of magnitude larger than that of CoFeB. In order to detect the strain sensitively and robustly against magnetic field fluctuation, the magnetic field modulation technique was applied to the GMR device. It was confirmed that the output voltage of the GMR device depends on the strain, and the gauge factor K = 46 was obtained by adjusting the applied DC field intensity and direction. We carried out the simulation based on a macro-spin model assuming uniaxial anisotropy, interlayer coupling between the free and pin layers, strain-induced anisotropy, and Zeeman energy, and succeeded in reproducing the experimental results. The simulation predicts that improving the magnetic properties of GMR films, especially reducing interlayer coupling, will be effective for increasing the output, i.e., the gauge factor, of the GMR strain sensors.

Flat Inkjet‐Printed Copper Induction Coils for Magnetostrictive Structural Health Monitoring: A Comparison with Bulk Air Coils and an anisotropic magnetoresistive sensor (AMR) Sensor

“…Arranged from low to high, these are 0.05 mH (/Ni/200), −0.08 mH (/Fe/200), −0.19 mH (/Fe/80), −0.44 mH (/Ni/80), and −0.71 mH (/control). Taken together, the values show that the /control actuator shows the best response, which is expected as FeSiB has a magnetostriction constant of 32 ppm, [ 16 ] which is higher than Fe and Ni. [ 17 ]…”

Time-dependent theory of optical electro- and magnetostriction

“…Experimental studies of electrostriction have also revealed interesting phenomena, such as the giant electrostriction [15][16][17][18][19][20][21][22][23][24][25], negative electrostriction [26,27], and deformations of liquid crystals [28,29] and biological cells [30]. On the theoretical side, electrostriction has also been under extensive study [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48].…”

Magnetostrictive effect in micro-dotted FeCo film coated surface acoustic wave devices

“…Magnetostrictive composites are a class of functional materials which can convert electromagnetic energy into mechanical energy and vice versa, and very promising for sensors and actuators with excellent performance [1][2][3][4][5][6][7][8]. Interestingly, higher magnetic sensitivity of the magnetostrictive thin-film and fast response towards external perturbation of the surface acoustic wave (SAW) devices makes them to be a good candidate of exploiting magnetic field sensing.…”