Low temperature 57Fe Mössbauer spectroscopy of Nd4.5Fe72Co3Cr2Al1B17.5 nanocrystallines ribbons

C. P. RAMOS; F. D. SACCONE; L. G. PAMPILLO

La Plata

Conferencia; LACAME08 - XI Latin American Conference on the Applications of the Mössbauer Effect; 2008

Exchange-spring magnets have been attracted great interest due to their technological potential. A method to produce them is the melt-spinning technique. By this mean, it is possible to get an amorphous ribbon-shaped material. Crystallisation of magnetic nanos- tructured phases are required in order to get a remanence enhancement and high energy products. These phases are coupled across their grain boundaries in a complex manner, which include the ferromagnetic-antiferromagnetic coupling. We detected this last cou- pling in exchange-biased hysteresis cycles measured at 7, 50, 100 and 200 K. In this work, we show the evolution of 57Fe hyperfine fields at low temperature, in those phases pre- cipitated after the crystallization of amorphous precursors of Nd4:5Fe72Co3Cr2Al1B17:5. The evolution of the fields is correlated with exchange-bias interactions.