XANES and XMCD study of Fe50Pt50 nanoparticles

FIGUEROA, S. J. A.; F. G. REQUEJO; S. J. STEWART; A. HERNANDO; P. DE LA PRESA

Buenos Aires

Congreso; Reunión Anual AFA; 2008

FePt nanoparticles (NPs) with strong magnetic anisotropy are currently of great interest due to their potential application in data storage medium and biomedicine [1]. In these systems the non-magnetic Pt stabilizes the magnetism of Fe instead of reducing it. However, the detailed mechanism that improves the magnetic properties is still being investigated [2]. On the other hand, special attention is currently being focused in investigating the mechanism involved in the transformation from disordered face-centered cubic structure to an ordered face-centered tetragonal one with high coercitivity and high anisotropy, in addition to the effect of coalescence of particles with annealing. In this work, we focus on the observation of the Pt magnetic moments of FePt particles synthesized by a wet chemical procedure using XMCD and studying throughout in-situ XANES experiments the changes due to annealing on as-prepared FePt NPs.