Fabrication of two-dimensional assembly of L1₀ FePt particles

Synthesis of L1₀ phase FePt particles which are two-dimensionally distributed on a substrate surface is studied. In order to obtain a fine particle assembly of L1₀ phase the low temperature ordering process of FePt from Fe/Pt multilayers is extended to multilayers of Fe-(MgO,Ag)/Pt-(MgO,Ag). In the annealing process of these multilayer structures Fe tends to migrate in MgO or Ag toward Pt while Pt tends to remain in the original position. Double layers of Fe-Ag/Pt are chosen to synthesize a two-dimensional distribution of ordered FePt particles. According to the Auger and micro-beam energy dispersion X-ray spectroscopy (EDX) analysis a part of Ag in Fe-Ag layer tends to move to the surface by annealing to embed the ordered FePt particles. Measurements of δM suggest that the particles are magnetically separated.