Temperature evolution of the magnetic ordering in nanocrystalline (Fe79Mn21)1-xCux with the Cu content

M. MIZRAHI; A. F. CABRERA; J. DESIMONI

Rio de Janeiro, Brazil

Conferencia; 9th International Conference on Nanostructured Materials; 2008

Magnetic nanostructured materials are one of the topics under research, especially due to the production of a large variety of new structures with interesting physical properties. The investigation and understanding of these properties can lead to the discovery of novel magnetic materials with potential applications in new technologies. In order to get deeper into the knowledge of the nanoestructurated metallic systems, powders of (Fe79Mn21)1-xCux (x = 0.00 to 0.30) were prepared by milling the elemental species in a horizontal vibrating device with steel balls and vial, under Ar atmosphere during 15 h at 33Hz. The structural analysis has been obtained by X-ray diffraction (XRD). Mössbauer spectroscopy (MS) at temperatures between 23 and 300K and AC-susceptibility measurements were performed to magnetically characterize the samples. XRD and MS results suggest the presence of two FCC-phases with different ordering temperatures. The AC-susceptibility measurements indicate the existence of a characteristic temperature which shifts to lower temperatures with increase the Cu content in agreement with MS results. These results provide evidence for a very complex magnetic and structural system, which present two clearly differentiated magnetic states.