The effects of high-energy milling on GdFe 2

Abstract

With the aim of better understanding, the effects of severe milling on the magnetic and structural properties of crystalline compounds, samples of the intermetallic compound GdFe 2 were milled up to 276h under inert atmosphere and characterized by X-ray diffractometry (XRD) and Mössbauer spectroscopy (MS). On milling GdFe 2 a strong segregation of the elements Gd and Fe initially occurred, and the characteristic peaks of the initial compound GdFe 2 in the XRD pattern are absent after 1 h of milling. MS and XRD results also show that the milled samples contain a mixture of three main components: the segregated elements, the initial compound and an amorphous alloy, with relative proportions that vary with milling time. At the longer milling times the process induces a solid-state reaction between these components leading to the formation of an amorphous solid solution of Gd and Fe. In these cases the Mössbauer spectra taken at 300, 84 and 4.2 K were fitted with a combination of a set of peaks typical of metallic α-Fe and a continuous distribution of hyperfine magnetic fields that are ascribed to the amorphous Gd-Fe phase.