LAUSR

Preparation of ordered CoPt on Si substrates by lithography-friendly deposition is significant for expanding future applications of spintronic devices. In this study, ordered CoPt alloys including the L10 phase with a maximum coercivity of 2.1 kOe are formed in electron-beam-deposited 11.4 nm thick Pt/Co bilayer thin films on Si/SiO2 substrates via interdiffusion during rapid thermal annealing (RTA). The effects of annealing temperature on the magnetic properties, crystal structures, cross-sectional elemental profiles, and surface morphologies of the films were analyzed by vibrating sample magnetometer (VSM), grazing incidence x-ray diffraction (GI-XRD), energy-dispersive x-ray spectroscopy (EDX), and scanning electron microscopy (SEM), respectively. For the as-deposited film, polycrystalline Pt was confirmed by uniform Debye–Scherrer rings of Pt. At 200 °C, interdiffusion between Co and Pt atoms in the film starts to be observed by EDX elemental mapping, and at 300 °C, alloying of Co and Pt atoms was confirmed by diffraction peaks corresponding to A1-disordered CoPt. At 400 °C, the in-plane coercivity of the film began to increase. At 700 °C, ordered CoPt alloys including the L10 phase were confirmed by superlattice diffraction peaks, indicating that the graded film contained L10-ordered CoPt. At 800 °C, a maximum coercivity of 2.1 kOe was observed by VSM, where the easy axis of magnetization was along the in-plane direction, further suggesting the formation of L10-ordered CoPt, and its. At 900 °C, deformation of the ordered CoPt alloys was observed by GI-XRD, and the grain size of the film reached a maximum.