Finite size effects and spin transition in ball-milled γ-(FeMn)30Cu70 nanostructured alloys

摘要: Abstract Fe15Mn15Cu70 alloys were prepared by high-energy ball milling over a wide range of grinding times from 15 min to 72 h. The corresponding magnetic properties followed means vibrating sample magnetometry, susceptibility and Mossbauer spectroscopy. By using Rietveld structural analysis high-resolution X-ray diffraction data, lattice parameter grain size correlations with magnetization coercive force carried out. Results revealed strong microstructural dependence the size, resembling finite size-driven transition at critical crystallite value around 8.5 nm. This behavior is endorsed partial low- high-spin according isomer shift results, unit-cell volume 50 A3 77 K attributed local variations interatomic spacing as consequence employed ball-milling procedure. Finally, concerns temperature behavior, samples exhibited freezing 61 K distribution relaxation ascribed presence interacting CuMn FeMnCu clusters.