Silicide formation and particle size growth in high-temperature-annealed, self-assembled FePt nanoparticles

摘要

L1_(0) FePt nanoparticle assemblies consisting of a few layers of 4-nm-diameter particles, are a potential data storage medium beyond 1 Tbit/in~(2). However, annealing at temperatures >500℃ is required to form the high anisotropy L1_(0) phase. Recent studies have shown a substantial drop in magnetization for T_(anneal)>650℃. We show that this reduction in magnetization is due to silicide formation as a result of a chemical reaction with the native oxide or Si substrate. We also show that full L1_(0) ordering is established only after annealing at 725℃ for 60 min and note that particle agglomeration occurs under these conditions.