Structural, thermal and hyperfine properties of Fe75Se25 powders prepared by mechanical alloying

Fe75Se25nanostructured powders have been produced by mechanical alloying in a high energy planetary ball-mill (P7) under argon atmosphere. Crystalline structure evolution, morphology changes, thermal measurements and hyperfine parameters variation were followed by scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS) microanalysis, X-ray diffraction (XRD), differential scanning calorimetry (DSC) and transmission Mössbauer spectroscopy (TMS) at 10 K and 293 K. SEM micrographs show progressive refinement of the particle sizes with milling time. XRD and TMS reveal the formation of Fe7Se8 phase and α-Fe (nanometric scale after 1 h of milling). β-FeSe hexagonal, Fe3O4 and FeO were also observed after 33 h of milling. Small amount of iron oxides is confirmed by DSC results showing an endothermic peak located at 584 °C.