Magnetic structure of FexCu100-x magnetoresistive alloys produced by mechanical alloying

FexCu100-x magnetoresistive alloys were produced by mechanical alloying. X- ray diffraction shows fcc structure. The room-temperature Mossbauer spectra evolves from an asymmetrical doublet below x = 25%, to a broad magnetic hy perfine field distribution above this concentration. Quadrupole splitting o f the doublet varies between 0.48 and 0.57 mm/s, and its isomer shift from 0.16 to 0.29 mm/s. Low-temperature Mossbauer spectroscopy displays a B-hf d istribution. Magnetization measurements display different features dependin g on concentration, from mictomagnetism to ferromagnetism. Low-temperature magnetoresistance is measured. Samples with x similar to 20% exhibit larger magnetoresistivity ratios. Bulk and hyperfine magnetic properties are corr elated in order to explain magnetoresistivity features of these samples.