Fabrication and characterization of ordered FePt nanoparticles

Ordered FePt nanoparticles with unique magnetic properties were obtained by direct deposition of FePt and C onto heated substrates at temperature above 450degreesC. The FePt particle sizes were controlled in the range from a few nanometers to 20 nm by adjusting the sputtering time from both the FePt and C targets. The tiny FePt nanoparticles (less than 3 nm) showed superparamagnetic behavior at room temperature. However, larger particles showed huge coercivities at room temperature (23 and 34 kOe for particles with average sizes of around 8 and 15 nm, respectively). For a certain FePt to C ratio, the films can show strong perpendicular anisotropy which is favorable for high density recording media. (C) 2003 American Institute of Physics.