Abstract
Highly ordered single-crystalline (001) FePt nanoparticles (NPs) with controllable sizes and a well-aligned easy axis were obtained by tuning the layer numbers and the SiO 2 -layer thickness of atomic-scale [Fe/Pt/ SiO 2 ] n multilayers deposited on SiO 2 Si substrates. After 700 °C annealing, quasi-self-assembled NPs with ultrahigh areal density of 1.0× 10 13 dots/in. 2 and large out-of-plane coercivity (H c,⊥ ) of 31 kOe were achieved. All particles were embedded into the SiO 2 substrates due to the low surface energy of SiO 2 , which significantly prevented the coarsening during annealing and resulted in a reduced particle size of 5.6 nm and small size distribution of 14.1%. © 2008 American Institute of Physics.