Structural Characterization of FePd, FePt, and CoPt Alloy Thin Films Epitaxially Grown on (001) Surface of Different Single-Crystal Materials

FePd, FePt, and CoPt alloy thin films are deposited on (001) single-crystal substrates of MgO, SrTiO₃, and LaAlO₃ at 600°C by using an ultra-high vacuum radio-frequency magnetron sputtering system. The c-axis distribution and the order degree are carefully studied. The FePd films deposited on MgO and SrTiO₃ substrates consist of L1₀(001) crystals with the c-axis perpendicular to the film surface. The FePd film deposited on LaAlO₃ substrate and the FePt and the CoPt films deposited on all the substrates include L1₀(100) crystals with the c-axis lying in the film plane. The c-axis distribution is influenced by the combination of film and substrate materials. Higher order degrees are observed for the film material CoPt <; FePt <; FePd and for the substrate material LaAlP₃ <; SrTiO₃ <; MgO. Order degree is influenced by atomic diffusion of deposited film material and by film strain caused by the lattice mismatch with substrate. The magnetic property reflects the c-axis distribution and the order degree.