Effect of pH on the magnetoimpedance properties of electrodeposited CoNiFe microtubes

Cobalt/nickel/iron (CoNiFe) magnetic samples were prepared by electrodeposition onto copper wires with a diameter of 50 μm. The magnetic properties of CoNiFe microtubes were systematically investigated at pH 2–3.5. It was observed that the composition, surface quality and magnetic and magnetoimpedance (MI) properties of the CoNiFe magnetic tubes were strongly affected by the pH of the electrochemical bath. The MI ratio of 123.2% at 160 kHz and a coercivity of 51.5 A/m were obtained for the sample that was produced in the pH 2.4 solution. The energy dispersive X-ray spectrum was also evaluated; this film had a composition of 22.14% Co, 59.94% Ni and 17.92% Fe, with no impurities.