Size effects, partially ordered FePt nanoparticles: Synthesis and easy axis alignment

The dissertation is focused on the size effects and the synthesis and easy axis alignment of partially ordered FePt nanoparticles. Larger nanoparticles have a higher anisotropy and higher chemical ordering than the smaller FePt nanoparticles after annealing. Additive Au is very effective in promoting chemical ordering in both larger and smaller FePtAu nanoparticles. Partially ordered L10 FePt and FePtAu particles have been synthesized. L10 FePt nanoparticles have been aligned along the easy axes after applying a magnetic field. L1 0 FePt nanoparticles with substantial dispersibility can get a substantial alignment. The degree of orientation is significant and the dependence of orientation on orienting field is in qualitative agreement with the calculations. Spin-coated FePt and FePtAu nanoparticles form a hcp ordered superlattice. The annealing destroys the assemblies via sintering based on SANS and magnetic measurements.