We demonstrate the possibility of diffusion formation of the chemically ordered L10-MnPt phase through the vacuum annealing of Pt(24 nm)/Mn(20 nm) and Pt(12 nm)/Mn(20 nm)/Pt(12 nm) layered stacks at 400 °C for 30 min. For the bi-layered stack annealed at 400 °C, the effect of Pt atoms segregation at the film/substrate interface was detected, which remained after annealing even at higher temperatures (500 °С and 600 °С) and prevented the whole homogenization of the chemical composition through the film depth. By contrast, for the tri-layered stack annealed at 400 °C, the presence of the additional Pt bottom layer enabled to change the rate and mechanism of reactive diffusion, leading to homogeneous distribution of components and enhanced crystallinity of the ordered L10-MnPt phase compared to the bi-layered sample. An explanation of the obtained experimental data is provided based on the fundamentals of mass transfer theory and its quantitative parameters (e.g. activation energy and diffusion coefficients).

The work was supported by the «Magnetism in Ukraine Initiative» (Project #9918 «Diffusion formation of MnPt-based L10-ordered antiferromagnetic thin film») and IEEE Magnetics Society. This work was also supported by the NATO Science for Peace and Security Program in the framework of the Project G5792 as well as by Ministry of Education and Science of Ukraine (Projects 0123U101257 and 0124U001266). The Ministry of Science, Innovation and Universities of Spain has also supported this work through a FPU grant (M. G.-S.). The authors would like to thank Dr. André Thiaville from Laboratoire de Physique des Solides, Université Paris-Saclay (France) for his support and valuable discussions regarding this manuscript

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