Anomalous grazing-incidence small-angle X-ray scattering investigation on the surface morphology of an FePt magnetic nanoparticle monolayer on functional modulated substrates

The structural stability and coalescence of self‐assembled FePt monolayer nanoparticles on functional substrates with/without an Au overlayer during annealing were studied. From X‐ray diffraction and the anomalous grazing‐incidence small‐angle X‐ray scattering techniques, the nanoparticles were found to be intact under the annealing process when a 5–10 nm overlayer of Au was deposited on top of FePt monolayer nanoparticles. From the simulation result, the particle size 4.5 ± 0.5 nm is typically unchanged, but the distance between particles is reduced from 7.5 ± 1.5 nm to 5.5 ± 1.1 nm after annealing. The results suggest that the 5 nm Au coverlayer is an effective diffusing barrier layer to prevent the FePt nanoparticles from sintering during the annealing process.