Magnetoresistance and the hall effect of the ordered alloys Fe$_{100-x}$Al$_x$ (25 $<x<$ 35 at.%)

The transverse magnetoresistance and the Hall effect of Fe$_{100-x}$Al$_x$ ordered alloys with $x$ = 26.5–34.1 at.% are studied at temperatures of 77 and 295 K. No saturation is found in the field dependences up to 17 kOe. The magnetoresistance is negative, depends nonmonotonically on the Al concentration, and reaches a maximum $|\Delta R/R|$ = 1.6% in the concentration range from 28 to 30 at.%. The coefficient of the anomalous Hall effect depends nonlinearly on the Al concentration and resistivity: it increases to a lesser extent as compared to the resistivity at $x$ = 26–30 at.% and decreases with increasing resistivity at $x >$ 30 at.%. An explanation is proposed for the observed anomalies in the magnetotransport properties in the framework of the model developed for the inhomogeneous magnetic microstructure of the Fe$_{100-x}$Al$_x$ ordered alloys.