Magneto-resistance, magneto-reactance, and magneto-impedance effects in single and multi-wire systems

► Improvement of magnetoimpedance and its field sensitivity in multi-wire systems. ► Improvement of magnetoresistance and its field sensitivity in multi-wire systems. ► Colossal magnetoreactance effect in soft ferromagnetic microwires. A systematic study of the magneto-resistance (MR), magneto-reactance (MX), and magneto-impedance (MI) effects in single and multiple glass-coated amorphous Co68B15Si10Mn7 microwires is reported. Our studies reveal that the MR, MX, and MI ratios and their corresponding magnetic field sensitivities strongly depend on the number of microwires in an array and on the distance between them. We find that increasing the number of microwires increases the MR and MI ratios and their field sensitivities (ηR and ηZ, respectively) but decreases the MX ratio and its field sensitivity (ηX). A similar trend is observed for the frequency dependence of these parameters. Increasing the distance between the wires is also found to decrease the MR and MI ratios but increase the MX ratio of the array considerably. From a sensor application perspective, it is interesting to note that for the case of a single microwire, the ηX reaches a value as high as 960%/Oe at a frequency of 1MHz, which is about 192 times of the ηR or ηZ (∼5%/Oe), revealing the possibility of developing ultrahigh sensitivity magnetic field sensors based on the principle of the MX effect.