Fabrication of ordered FePt nanoparticles with a cluster gun

In this study we present a technique to obtain ordered fct FePt particles embedded in a C matrix. FePt nanoparticles are formed inside a high-pressure sputtering cell, called a particle gun (PG), and subsequently deposited on the substrate through a small orifice. These particles have a uniform size distribution with an average particle size that can be controlled in the range of 3-10 nm by adjusting the sputtering cell pressure, power, distance between the magnetron and the orifice, and by using a liquid nitrogen cooling jacket. The particles are converted to the L1(0) phase as they pass through a specially designed heating stage, attached to the top of the PG, heated by halogen lamps, thus avoiding alloying and oxidation effects. A strong dependence of coercivity on both the particle size and temperature was observed. (C) 2003 American Institute of Physics.