The results of experimental and theoretical studies of the influence of the current value on the characteristics of anisotropic magnetoresistive magnetic field sensors based on FeNiCo alloy with a "barber-polе" structure are presented. A significant difference was found between the volt-oersted characteristics of the forward and reverse strokes with an increase in the intrinsic current caused by the input supply voltage at sufficiently high external magnetic fields. A theoretical calculation of the volt-oersted characteristic was carried out within the framework of the model of one-dimensional heterogeneity of the magnetization distribution, which coincides with the experimental curves of the forward path.