Giant magnetoresistive properties of FexAu100-x alloys produced by mechanical alloying

The FexAu100-x allovs were produced for the first time by mechanical alloyi ng. Resistance of samples with iron concentrations of x = 15. 20. 25. and 3 0 at % were measured at 77 K under an applied field of 14 kOe. A maximum in magneto resistive ratio (Deltap,p) of 3.5% was obtained for Fe(25)AU(75). Samples were annealed in order to enhance magnetoresistive properties. Thes e samples exhibit larger ratios. primarily due to the elimination of defect s. X-ray diffraction Mossbauer spectroscopy and magnetoresistance measureme nts were performed, in order to correlate bulk and hyperfine magnetic prope rties with crystalline structure. X-ray diffractograms show an FCC structur e, with no evidence for a BCC one. (C) 2001 Elsevier Science B.V. All right s reserved.