Magnetoresistance of the Fe72CU1V3Si16B8 amorphous alloy annealed by direct current Joule heating

The longitudinal magnetoresistance of the Fe72Cu1V3Si16B8 melt spun ribbon in its as-cast and nanocrystalline state has been studied. Successive thermal treatments with increasing in current intensity from 33 to 43 A/mm(2) were applied for a fixed time (t(an) = 180 s) in order to evolve nanocrystalline structure. Nanocrystals are detected by X-ray diffraction after treatment around 760 K. The volumetric fraction of the crystalline phase was calculated from the effective resistivity of the sample and by enthalpy data. The increases of alpha-Fe(Si) crystallites over 38% with residual amorphous matrix lead to the sign change from Positive to negative magnetoresistance. The saturation in concentration of silicon in precipitated a-Fe crystallites to the value of 19 at % Si has been observed. (C) 2002 Elsevier Science B.V. All rights reserved.