THE EFFECTS OF HIGH-ENERGY MILLING ON GDFE2

With the aim of better understanding, the effects of severe milling on the magnetic and structural properties of crystalline compounds. samp les of the intermetallic compound GdFe2 wire milled up to 276 h under inert atmosphere and characterized by X-ray diffractometry (XRD) and M ossbauer spectroscopy (MS). On milling GdFe2 a strong segregation of t he elements Gd and Fe initially occurred, and the characteristic peaks of the initial compound GdFe2 in the XRD pattern are absent after 1 h of milling. MS and XRD results also show that the milled samples cont ain a mixture of three main components: the segregated elements, the i nitial compound and an amorphous alloy, with relative proportions that vary with milling time. At the longer milling times the process induc es a solid-state reaction between these components leading to the form ation of an amorphous solid solution of Gd and Fe. In these cases the Mossbauer spectra taken at 300, 84 and 4.2 K were fitted with a combin ation of a set of peaks typical of metallic alpha-Fe and a continuous distribution of hyperfine magnetic fields that are ascribed to the amo rphous Gd-Te phase. (C) 1997 Elsevier Science B.V. All rights reserved .