Study of Giant Magneto-Impedance Behavior in Co–Fe Based Amorphous/Nanocrystalline Materials

Abstract

Giant magneto-impedance (GMI) behavior have been studied in melt spun Co71−XFeXCr7Si8B14 (X = 0 2 32 4 6 8, and 12 at%) alloys. The addition of Fe in the system changed the saturation magnetostriction constant from negative to positive values. The GMI property was measured with a driving current of 5mA and 4MHz frequency using a spectrum analyzer. The GMI ratio increased with the increase of the applied dc field and became maximum at a field Hk known as the anisotropy field of the materials. The maximum of GMI ratio (GMImax) depended on the Fe content and was maximum (12%) for Fe = 4 at% for the alloys in the as-melt spun state. Substantial increase of GMImax to 66% for Fe = 4 at% was observed after annealing the sample at 673 K.