The origin of enhanced L10 chemical ordering in Ag-doped FePt nanoparticles

FePt and Ag-doped FePt nanoparticles were synthesized by the thermolysis and polyol reductions. The A1-to-L10 transformation of the nanoparticles was investigated by differential scanning calorimetry (DSC) at different scanning rates, and the DSC endothermic peak shifts were monitored and used for the Kissinger analyses. The activation energy for the phase transformation was determined to be ∼251 and ∼219 kJ/mol for the pure and doped FePt nanoparticles, respectively. The decrease in the activation energy is the evidence of increased number of vacancies, which turned out to be the origin for the reduced L10 chemical ordering temperature in doped FePt.