Phase transformation and magnetic moment in FePt nanoparticles

Abstract

The phase transformation from fcc to ${\text{L1}}_0$ in FePt nanoparticles was investigated in both thick film samples and self-assembled arrays as a function of the annealing temperature, using transmission electron microscopy, x-ray diffraction, differential scanning calorimetry, and magnetometry. A significant fraction of the surfactant decomposes into gaseous products below 500 °C, removing the steric barrier between particle cores. This causes the particles to coalesce at the same annealing temperatures where the transformation to the high anisotropy phase occurs.