Temperature evolution of the hyperfine parameters in the nanostructured Fe-Mn-Cu system

M. MIZRAHI, A. F. CABRERA Y J. DESIMONI.

Foz do Iguazú

Simposio; XIV International Conference on Hyperfine Interactions & XVIII International Symposium on Nuclear Quadrupole Interactions; 2007

Nanogranular magnetic materials have been received much attention in the last decade due to their rich phenomenology and intensively researched from the fundamental and technological point of view. Frustration of the exchange interactions, disorder and surface effects have been claimed to interpret their structural and magnetic properties.  In order to get deeper insight into the nanoestructurated metallic systems, allowed powders of (Fe79Mn21)1-xCux (x = 0 to 0.3) were prepared by milling the elemental species in a horizontal vibrating device with steel ball and vial, under Ar atmosphere during 15h at 33Hz. In this work we report the evolution of hyperfine parameters with the Cu content and temperature obtains by Mössbauer spectroscopy. Results indicate that the Cu addition favors the formation of a FCC phase with two different magnetic states at room temperature, a magnetic and a paramagnetic one. Thermal evolution of the Mössbauer spectra revealed the occurrence of a magnetic ordering along a wide temperature range. This behavior could be related to Fe atoms in FCC structure having different environments and grain size distribution.