Giant magnetoimpedance effect of Co68.15 Fe4.35 Si12.5 B15 amorphous wire in the presence of magnetite ferrofluid

•Amorphous Co-based wires display GMI effect and this feature is of potential interest for developing small magnetic field sensors and biosensors.•This manuscript is dealing with the improvement of the GMI response of an amorphous Co-based wire/magnetite ferrofluid.•The effect of ferrofluid presence in the sensing element is also analyzed.•The results show that GMI maximum increases in a 100% at 4.5 MHz and the sensitivity also does about a 150%.•Amorphous Co-based wires display giant magneto impedance effect (GMI) and this intrinsic feature is of potential interest for developing small magnetic field sensors and biosensors.•This manuscript is dealing with the improvement of the GMI response of an amorphous Co68.15Fe4.35Si12.5B15 wire/magnetite ferrofluid.•The effect of ferrofluid presence in the sensing element is also analyzed.•The results show that GMI maximum increases in a 100% at 4.5 MHz and the sensitivity also does about a 150%.

Giant magnetoimpedance effect (GMI) in Co68.15 Fe4.35 Si12.5 B15 amorphous wire was studied in the presence of magnetite ferrofluid and without it. Magnetite nanoparticles for ferrofluid were prepared by the traditional wet chemistry co-precipitation method. GMI was measured in the frequency range of 2 to 6 MHz. The maximum value of GMI value of the ferrofluid covered amorphous wire was increased in all frequency intervals in comparison with GMI response of the wire non-covered by ferrofluid. These results open a new way of increasing magnetoimpedance effect value useful for sensor applications.