Giant magneto-impedance effect in sandwiched FeSiB/Cu/FeSiB films

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