Early stages of direct $L10$ FePt nanocluster formation: The effects of plasma characteristics

The formation of FePt nanoclusters via gas condensation has attracted a great deal of attention. The clusters normally form with the magnetically soft $A1$ structure rather than the desired $L10$ structure with high magnetocrystalline anisotropy. This work has examined the effects of plasma characteristics on the early stages of order in the formation $L10$ FePt nanoclusters via inert gas condensation. The plasma characteristics have been modified to control ion density in the nanocluster condensation region. Increased ion density results in more cluster-ion collisions. The energy imparted to the clusters as a result of these collisions allows atomic rearrangements to form the ordered structure. The results indicate that controlled ion density directly impacts the early stages of FePt nanocluster ordering, according to high-resolution electron microscopy structure observations and coercivity measurements.