Phase transformation and magnetic moment in FePt nanoparticles

The phase transformation from fcc to 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 500degreesC, 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. (C) 2003 American Institute of Physics.