Giant Magneto-Impedance Effect in Sandwiched FeSiB/Cu/FeSiB Films

Giant magneto-impedance (GMI) effect has been realized in the sandwiched FeSiB/Cu/FeSiB films. With magnetic field H_a and ac current applied along the longitudinal direction of the sample, the GMI ratio increases with the increasing H_a, reaching a positive maximum value, and then decreases to negative values with further increase of magnetic field. Field dependence of the GMI ratio also indicates that the magnetic field corresponding to the maximum GMI ratio is different for various frequencies. The positive maximum GMI ratio is 17.2% for H_a=1600A/m and frequency of 3 MHz. In addition, the films display a large negative GMI ratio with a magnetic field applied along the transverse direction and the value of the GMI ratio is about -13.4% for H_a=5600A/m and frequency of 3 MHz.