Reduction of ordering temperature in substituted FePtNi nanoparticles formed by chemical synthesis

In this paper, we used Ni substitution for Pt to reduce the transformation temperature of the FePt alloys where FePtNi nanoparticles were fabricated by chemical synthesis. M vs T data showed a blocking temperature at around 35 K, consistent with the tiny size (2-3 nm) of the particles. DSC data indicate a structural transformation from fcc to fct at a temperature about 70°C lower in Fe₆₀(Pt_0.7Ni_0.3)₄₀ than in Fe₅₈Pt₄₂ as confirmed by XRD and hysteresis loop measurements. Mossbauer spectra and relation of coercivity with annealing temperature and time were also presented.