Features of Ordered Nanostructure Formation in Ultrathin FePd Films Annealed in Hydrogen

Ultrathin FePd (5 nm) films of equiatomic composition were prepared by magnetron sputtering on the SiO2 (100 nm)/Si (001) substrates at room temperature. Effect of environment (vacuum or hydrogen), temperature and annealing duration on the phase transformation from disordered A1 FePd phase into the ordered L10 FePd phase, structure, surface morphology and magnetic properties of the films were studied. In comparison with annealing in vacuum the hydrogen treatment accelerates the ordering process. Wherein, introduction of hydrogen atoms into the FePd film lead to change in electronic structure and causes a reversible effect on magnetic states: ferromagnetic ↔ paramagnetic. With an increase in the duration and temperature of annealing in hydrogen due to its reversible effect on magnetism, the magnetic properties and states change: soft magnetic → paramagnetic → hard magnetic → paramagnetic.