The structure of L10-FePt nanoparticles in the presence of Ag

Temperature above 600°C during the fabrication process is required to form the L10 compound ordering phase in FePt nanoparticles. The L10-FePt nanoparticles are ferromagnetic with high magnetic anisotropy. Practically, another ordering that is required is the orientation of their crystal c axis perpendicular to the plane of the nanolayer. The effects of the presence of Ag in reducing the transition temperature and making FePt nanocrystals in the L10-FePt phase aligned, in this work, have been studied and determined. The results of XRD analysis indicate that in fabrication using the co-sputtering method, firstly, the presence of Ag before annealing gives rise to the decline of the c parameter of the crystal lattice. This result of XRD analysis has been compared with the result of the RKKY exchange interaction model as an experimental confirmation of this model. Secondly, during annealing, with the formation of FePt-Ag nanostructure, the easy axis of FePt nanoparticles in the L10-FePt phase appears parallel to each other. These results, which are the consequence of the presence of Ag, are obtained by studying FE-SEM images, XRD patterns, and magnetic characterization. Keywords