Electrochemical produced magnetic composite wires using as coil-less fluxgate sensor

In this study, Ni80Fe20 and Co19Ni49.6Fe31.4 layers have been electrodeposited onto a twisted copper wire. Chronoamperometry techniques were used to study the nucleation mechanism process, while electrochemical impedance spectroscopic (EIS) techniques for corrosion studies. Electrochemical nucleation and growth mechanism analysis of NiFe and CoNiFe layer on Cu substrates under torsional strains and stress were made on the basis of Scharifker-Hills model and electrochemical impedance spectroscopy (EIS).The magnetoimpedance (MI) and coil-less fluxgate (CF) properties of electrodeposited produced magnetic samples are presented. The effects of applied torsion and tensile stress during the electrodeposition process on MI and CF properties have been also investigated. Wires produced at zero torsional strain have no helical anisotropy show a nearly zero CF effect. MI effect magnitude decreases with increasing applied torsion during the electrodeposition process. This can be related to the increase in the induced helical anisotropy with increasing torsion. The samples produced under torsional strain shows a linear change in CF output at the low-frequency range. At higher frequencies, CF output shows two linear slopes. It is also found that the slope of the CF curve depends on the direction of induced anisotropy. A maximum sensitivity of 150 V/T, which is a comparable value with a typical fluxgate sensor, is observed at 20 kHz driving-current frequency and 67 mA driving current for a wire produced under 59 rad/m torsional strain for Co19Ni49.6Fe31.4. A maximum sensitivity of 54 V/T was observed at 50 kHz driving-current frequency and 54 mA driving-current on wire produced under 89.7 rad/m torsion for Ni80Fe20 sample.