Asymmetrical magneto-impedance effect in NiFe/SiO2/Cu composite wire with a sputtered NiFe seed layer

In this work, a new type of asymmetrical magnetoimpedance (AMI) effect has been found in a new type of NiFe/SiO2/Cu composite wire without applying any dc-biased magnetic field, in which NiFe/SiO2/Cu composite wires were fabricated by sputtering a NiFe seed layer on the SiO2 layer and then electroplating another NiFe layer on the NiFe seed layer. A magnetization rotation model based on the coupling effect with bias field in the seed layer and the pinning effect by defects in the wire has been used to qualitatively explain the AMI profiles observed.