Magnetic Anisotropy and Giant Magnetoimpedance in NiFe Electroplated on Cu Wires

摘要

Magnetic anisotropy of NiFe films electrodeposited on Cu wires was studied. The influence of current density, magnetic field and strain applied during deposition on the anisotropy constant and easy axis orientation was investigated using AC hysteresis loop tracer and magneto-impedance measurements. Magnetic field applied during the electrodeposition induces weak magnetic anisotropy with the easy axis parallel to the field and features typical for atomic pair ordering mechanism. Strain applied to the wire during electrodeposition produces magnetoelastic anisotropy due to the back-stress after strain removal. By the proper choice of deposition conditions both the anisotropy constant and the easy axis orientation can be easily controlled. Using torque strain during deposition controllable helical anisotropy, suitable for coil-less fluxgate sensors, has been obtained.