Magnetic and Structural Properties of Magnetoresistive FexAu100-x Alloys Produced by Mechanical Alloying

SOCOLOVSKY, L. M.; SÁNCHEZ, F. H.; SHINGU, P. H.

Physica B - Condensed Matter

Elsevier

Lugar: Holanda; Año: 2002 vol. 320 p. 149 - 152

0921-4526

FexAu100Àx alloys have been produced for the first time by mechanical alloying. X-ray diffractograms show FCCpeaks. From the X-ray diffracion peak-widths we estimate the final grain size, which vary with x from 112 nm (forx 1⁄4 15) to 32 nm (for x 1⁄4 30). Lattice parameter decreases with concentration (minimum 0.401 nm at x 1⁄4 30), butabove Vegard’s law values. Susceptibility measurements show cluster-glass behaviour. Critical temperatures areconsistently lower than similar alloys produced by arc melting followed by fast quenching. A magnetic phase diagram ispresented. Giant magnetoresistance is present in all samples, with a maximum at x 1⁄4 25: This effect is caused by thedispersion of small iron clusters produced by the mechanical work.